Basic IGCSE Second Year Class Notes On Physicsramadan.50megs.com/download/Microsoft Word - IGCSE...b) Light i) Reflection of light ii) Refraction of light iii) Lenses and thin converging

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Basic IGCSE

Second Year Class Notes On Physics

First Edition

By

R. K. Abu-Msameh Visit My Educational Web Site On Physics

http://ramadan.50megs.com

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Dear Student: I prepared this simple text to help you study and plan well to your IGCSE exam in physics. This simple text provides you with fundamental informationfundamental informationfundamental informationfundamental information that you must know and understand to handle “paper-1” and “paper-2” of the exam. For “paper-3” you need the advanced notesadvanced notesadvanced notesadvanced notes and for “paper-6” you need the experiments manualexperiments manualexperiments manualexperiments manual. By the fundamental information fundamental information fundamental information fundamental information notes you should be able to demonstrate knowledge with understanding in relation to scientific phenomena, facts, laws, definitions, concepts, theories, scientific vocabulary, terminology and conventions including of symbols, quantities, and units. See appendix. This notebook addresses the following topics from IGCSE syllabus. 1) Thermal Physics

a) Molecular Model i) States of matter ii) Molecular model iii) Evaporation iv) Pressure changes

b) Thermal Properties i) Thermal expansion of solids, liquids, and gasses ii) Measurement of temperature iii) Thermal capacity iv) Melting and boiling

c) Transfer of thermal energy i) Conduction ii) Convection iii) Radiation iv) Consequences of energy transfer

2) Properties of Waves a) Wave Properties b) Light

i) Reflection of light ii) Refraction of light iii) Lenses and thin converging lens iv) Dispersion of light v) Electromagnetic spectrum

c) Sound 3) Electricity and magnetism

a) Introductory Electronics i) Cathode Rays ii) Oscilloscope iii) Action Circuits

Please study these notes carefully and rely on understanding rather than on memorizing. If you have any suggestions please let me know and we will discuss them. With Best Regards, Ramadan K. Abu-Msameh Web site: http://ramadan.50megs.comhttp://ramadan.50megs.comhttp://ramadan.50megs.comhttp://ramadan.50megs.com

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Table Of Content Thermal Physics.............................................................................4

Simple Kinetic Molecular Modal of Matter .....................................................................................4 (a) States of Matter .......................................................................................................................4 (b) Molecular Modal ....................................................................................................................6 (c) Evaporation...........................................................................................................................11 (d) Pressure Changes..................................................................................................................13

Thermal Properties .........................................................................................................................15 (a) Thermal Expansion of Solids, liquids and gases ..................................................................15

Expansion ...............................................................................................................................15 Expansion of solids ................................................................................................................16 Expansion of liquids...............................................................................................................20 Expansion of gases .................................................................................................................24

(b) Measurement of Temperature...............................................................................................26 Temperatures ..........................................................................................................................27 Thermometers.........................................................................................................................27 Celsius Scale ..........................................................................................................................29 Kelvin Scale ...........................................................................................................................29 Mercury Thermometers..........................................................................................................29 Alcohol Thermometer ............................................................................................................30 Clinical Thermometers ...........................................................................................................30 Thermocouple Thermometers ................................................................................................31

(c) Thermal Capacity..................................................................................................................32 Skills.......................................................................................................................................34

(d) Melting and Boiling..............................................................................................................35 Melting and Freezing Points ..................................................................................................35 Latten Heat .............................................................................................................................36 Boiling Point ..........................................................................................................................37

Transfer of Thermal Energy...........................................................................................................38 (a) Conduction............................................................................................................................38 (b) Convection............................................................................................................................40 (c) Radiation...............................................................................................................................44 (d) Consequences of Energy Transfer ........................................................................................49

Properties of Waves, Including Sound and Light.........................50 General wave properties.................................................................................................................50

Skills.......................................................................................................................................54 Light ...............................................................................................................................................55

(a) Reflection of Light................................................................................................................55 (b) Refraction of Light ...............................................................................................................57 (c ) Thin Converging Lenses......................................................................................................61

Problems.................................................................................................................................65 (d) Dispersion of Light ...............................................................................................................66 (e) Electromagnetic Spectrum....................................................................................................68

Sound..............................................................................................................................................70 Electricity and Magnetism ...........................................................73

Introductory Electronics .................................................................................................................73 (a) Cathode Rays ........................................................................................................................73 (b) Simple Treatment of cathode ray oscilloscope.....................................................................77 (c) Action and Use of Circuit Components................................................................................80

Thermistors.............................................................................................................................80

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Light-Dependent Resistor (LDR)...........................................................................................83 Reed Switches ........................................................................................................................85 Potential Divider ....................................................................................................................87

Questions Bank............................................................................89 Thermal Physics .............................................................................................................................89

States of Matter ..........................................................................................................................89 Molecular Modal ........................................................................................................................89 Evaporation ................................................................................................................................89 Pressure Changes........................................................................................................................90 Expansion ...................................................................................................................................90 Expansion of Liquids .................................................................................................................90 Expansion of Gases ....................................................................................................................90 Temperatures ..............................................................................................................................91 Thermometers.............................................................................................................................91 Celsius Scale ..............................................................................................................................91 Kelvin Scale ...............................................................................................................................91 Mercury Thermometers..............................................................................................................91 Alcohol Thermometer ................................................................................................................91 Clinical Thermometers ...............................................................................................................91 Thermocouple Thermometers ....................................................................................................91 Thermal Capacity .......................................................................................................................92 Melting Point..............................................................................................................................92 Freezing......................................................................................................................................92 Boiling Point ..............................................................................................................................92 Conduction .................................................................................................................................92 Convection .................................................................................................................................93 Radiation ....................................................................................................................................93

General wave properties.................................................................................................................94 General wave properties.............................................................................................................94 Reflection of Light .....................................................................................................................94 Refraction of Light .....................................................................................................................94 Thin Converging Lenses ............................................................................................................95 Dispersion of Light.....................................................................................................................95 Electromagnetic Spectrum .........................................................................................................96 Sound..........................................................................................................................................96

Electricity and Magnetism .............................................................................................................96 Cathode Rays..............................................................................................................................96 Simple Treatment of cathode ray oscilloscope ..........................................................................96 Thermistors.................................................................................................................................97 Light-Dependent Resistor (LDR)...............................................................................................97 Reed Switches ............................................................................................................................97 Potential Divider ........................................................................................................................97

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Second year in IGCSE Physics Table of Contents

2 Thermal Physics Page No. In Your Textbook

2.1 Molecular Model

a States of matter b Molecular model c Evaporation d Pressure changes

2.2 Thermal Properties

a Thermal expansion of solids, liquids, and gasses

b Measurement of temperature c Thermal capacity d Melting and boiling

2.3 Transfer of thermal energy

a Conduction

b Convection

c Radiation

d Consequences of energy transfer

3 Properties of Waves

3.1 Wave Properties

3.2 Light

a Reflection of light b Refraction of light c lenses and thin converging lens d Dispersion of light e Electromagnetic spectrum

3.3 Sound

4 Electricity and magnetism

4.6 Introductory Electronics a Cathode Rays b Oscilloscope c Action Circuits

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Thermal Physics Simple Kinetic Molecular Modal of Matter

(a) States of Matter

2 Thermal Physics Where to go! 2.1 Simple Kinetic Molecular Modal of Matter E1161

A States of matter E116 Core-1 State the distinguishing properties of solids, liquids, and gases E116 Objectives: The student should be able to …

1. List the states of matter. 2. Define solid, liquid, and gas. 3. Explain why liquids are used to transfer forces in hydraulic machines. 4. List the properties of solids, liquids and gases

1. List the states of matter. Solids, liquids, gases

2. What is a solid? A solid consists of atoms that are bounded together in a rigid structure. As atoms in a solid do not have enough energy to break out of the structure, solids do not flow. The hardness of a solid depends on the arrangements of its atoms. For example, the element carbon can exist in the soft form, graphite, or as one of the hardest solid forms on Earth, diamond.

3. What is a liquid? A liquid is a substance that flows more freely as a gas. When a substance is liquid its molecules possesses more energy than they have been in solids but less energy than they have when it is a gas. This allows liquid to flow and take the shape of its container. Liquids are much harder to compress than gases.

4. What is a gas? A gas is a state of matter in which molecules are so energetic and completely free to move. When a gas is released inside a container, its molecules move randomly, spreading out to fill the whole container.

5. Why liquids are used to transfer forces in hydraulic machines rather than gases? Because they are much harder to compress than gases.

6. List the properties of solids 1. Have definite shape and volume 2. Their molecules are very close to each other 3. Their molecules have strong forces of attraction and repulsion 4. Their molecules vibrate about fixed positions

1 Note: ‘E’ stands for “Explaining Physics”. For example, E166 means page 116 in explaining physics

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7. List the properties of liquids 1. Do not have fixed shape but have definite volume 2. Can flow 3. Their molecules are further apart from each other. 4. Their molecules have weaker forces of attraction and repulsion 5. Their molecules vibrate but can change position with other

molecules. 8. List the properties of gases

1. Do not have fixed shape, and definite volume 2. Can flow 3. Their molecules are much further apart from each other. 4. Their molecules have negligible forces between them. 5. Their molecules move randomly in all directions

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(b) Molecular Modal

2 Thermal Physics Where to go! 2.1 Simple Kinetic Molecular Modal of Matter E4.12, E116

B Molecular Modal E4.1, E116

Core-1 Describe qualitatively the molecular structure of solids, liquids, and gases E116

Core-2 Interpret the temperature of a gas in terms of the motion of its molecules E116

Core-3 Describe qualitatively the pressure of a gas in terms of the motion of its molecules E116

Core-4 Describe qualitatively the effect of a change of temperature on the pressure of gas at a constant volume E116

Core-5 Show an understanding of the random motion of particles in a suspension as evidence for the kinetic molecular modal of matter E116

Core-6 Describe this motion ( sometimes known as Brownian motion) in terms of random molecular bombardment E116-E117

Sup-1 Relate the properties of solids, liquids, and gases to the forces and distances between molecules and to the motion of the molecules. E116

Sup-2 Show an appreciation that massive particles may be moved by light fast-moving molecules. E116

Objectives: The student should be able to …

1. State the basic assumptions of the KMTM 2. List the properties of solids 3. List the properties of liquids 4. List the properties of gases 5. Explain why solids have definite shape and volume 6. Explain why liquids do not have fixed shape but have definite volume can flow 7. Explain why gases do not have fixed shape, and definite volume but can flow 8. Explain why gases are easily compressed 9. Explain why liquids are used to transfer forces in hydraulic machines 10. Explain why a spring returns to its original shape after removing the stretching force 11. Explain why a spring returns to its original shape after releasing compression from it 12. Define temperature based on the molecular model 13. What is the relation between temperature and kinetic energy of molecules 14. What does it mean when an object is hotter than another object based on the molecular

model 15. Explain how gases produce pressure on the walls of their containers 16. Explain how temperature increases the pressure of gases 17. Explain how low temperature decreases the pressure of gases 18. What does a Brownian motion mean 19. Explain an experiment to demonstrate the Brownian motion.

2 E4.1 means section 4.1 in “Explaining Physics”

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1. What are the basic assumptions of the KMTM?

1. All matter is made up of tiny particles called molecules.

2. Molecules are constantly in motion and have kinetic energy.

3. Molecules are separated by small spaces called intermolecular distances.

4. Molecules are tide by forces called intermolecular forces

5. The intermolecular forces are attractive forces when the molecules are close to each other and become repulsive forces when they get too close to each other.

2. List the properties of solids

1. Their molecules are very close to each other 2. Their molecules have strong forces of

attraction and repulsion 3. Their molecules vibrate about fixed positions

3. List the properties of liquids

1. Their molecules are further apart from each other. 2. Their molecules have weaker forces of attraction

and repulsion 3. Their molecules vibrate but can change position

with other molecules.

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4. List the properties of gases

1. Their molecules are much further apart from each other. 2. Their molecules have negligible forces between them. 3. Their molecules move randomly in all directions

5. Why do solids have definite shape and volume? 1. Their molecules are very close to each other 2. Their molecules have strong forces of attraction and repulsion 3. Their molecules vibrate about fixed positions

6. Why do not liquids have fixed shape but have definite volume can flow?

1. Their molecules are further apart from each other. 2. Their molecules have weaker forces of attraction and repulsion 3. Their molecules vibrate but can change position with other molecule

7. Why do not gases have fixed shape, and definite volume but can flow?

1. Their molecules are much further apart from each other. 2. Their molecules have negligible forces between them. 3. Their molecules move randomly in all directions

8. Explain why gases are easily compressed?

Gases are easily compressed because their repulsive intermolecular forces are negligible.

9. Why liquids are used to transfer forces in hydraulic machines? Because they are much harder to compress than gases.

10. Explain why a spring returns to its original shape after removing the stretching force? When the spring is extended by a load, the intermolecular spaces are increased and the attractive forces between the molecules cause it to return to its original length when the load is removed.

11. Explain why a spring returns to its original shape after releasing compression from it? When the spring is compressed by a force, the intermolecular spaces are decreased and the repulsive forces between the molecules cause it to return to its original length when the force is removed.

12. Define temperature based on the molecular model? Temperature is a measure of the average kinetic energy possessed by each molecule of the substance

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13. What is the relation between temperature and kinetic energy of molecules? The hotter the object, the more kinetic energy its molecules have and the faster they move.

14. What does it mean when an object is hotter than another object based on the molecular model? It means the average kinetic energy of each molecule of the hot object is greater than the average kinetic energy of the colder one.

15. Explain how gases produce pressure on the walls of their containers? Gas molecules are in a state of continuous motion in all directions, and they are constantly bombarding the walls of the container. When the molecules bounce off the walls, they produce an outward force on the walls which causes the outward pressure of the gas on the walls of the container.

16. Explain how temperature increases the pressure of gases? When the temperature rises, the gas molecules gain kinetic energy and move faster and thus strike the container wall more frequently and with greater force. Therefore, the total force exerted per unit area of the walls is greater and the pressure increases.

17. Explain how low temperature decreases the pressure of gases? When the temperature decreases, the gas molecules lose kinetic energy and move slower and thus strike the container wall less frequently and with less force. Therefore, the total force exerted per unit area of the walls is less and the pressure decreases.

18. What does a Brownian motion mean? Brownian motion is a random motion.

19. Explain an experiment to demonstrate the Brownian motion. 1. Inject smoke in a small glass cell. 2. Illuminate the cell by a filament lamp. 3. View the glass cell using a microscope. 4. Observation

When we view the glass cell, the smoke particles reflect the light ray falling on them and see bright specks against a dark background moving in random direction.

5. Analysis: The relatively large smoke particles are surrounded by much smaller and faster air molecules. Air molecules bombard the smoke particles randomly from all directions causing the smoke particles to move randomly.

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(c) Evaporation


C Evaporation E154

Core-1 Describe evaporation in terms of the escape of more-energetic molecules from the surface of a liquid. E154

Core-2 Relate evaporation and consequent cooling E154, E155

Sup-1 Demonstrate an understanding of how temperature , surface area, and drought over a surface influence evaporation E154, E155

Objectives: The student should be able to

1. Define evaporation 2. State at what temperature evaporation occurs 3. Explain what effect evaporation may leave on its liquid 4. List examples that show the cooling effect of evaporation 5. Explain how evaporation cools liquids 6. List the factors which increase evaporation 7. Explain why the increase in temperature increases evaporation 8. Explain why the increase in liquid surface area increases evaporation 9. Explain why winds and drought increase the rate of evaporation

1. Define evaporation? Evaporation is the escape of molecules of liquids from its surface.

2. At what temperature evaporation occur? At any temperature

3. What effect evaporation may leave on its liquid? It will cool the liquid

4. List examples that show the cooling effect of evaporation? 1. When the human body becomes hot, sweating occurs to cool the body by

evaporation 2. Liquids are kept in pots of porous materials to cool them by evaporation 3. In refrigerators, the evaporation of the volatile liquid (Freon) in their tubes causes

the continuous cooling. 4. When a volatile liquid is placed on the hand, its evaporation causes the hand feel

cold (local anthesia)

5. Explain how evaporation cools liquids? The molecules of a liquid are in continuous random motion having an average kinetic energy proportional to its temperature. The most energetic molecules near the surface of the liquid can over come the attractive forces of other molecules and can escape from the surface into the air above it, thus the average kinetic energy decreases and the temperature of the liquid drops.

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6. List the factors that increase evaporation? 1. Increase in the temperature of the liquid 2. Increase in the surface area of the liquid 3. Air passing across the liquid surface

7. Why the increase in temperature increases evaporation?

The increase in temperature makes the molecules move faster, so that more of them have enough energy to escape from the surface.

8. Why the increase in liquid surface area increases evaporation? Large surfaces have more fast molecules than small surfaces. Thus, more molecules have the chance to escape from the liquid surface.

9. Why winds and drought increases the rate of evaporation? Winds carry away the evaporated molecules from the surface and allow more molecules to evaporate.

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(d) Pressure Changes


D Pressure Changes E134

Core-1 Relate the changes in volume of a gas to change in pressure applied to the gas at constant temperature

See Expansion E134, E135, E136

Sup-1 Recall and use the equation pV=constant at constant temperature E136, E137 Objectives: The student should be able to …

1. Explain the relation between gas pressure and volume at constant temperature 2. State Boyle's law 3. Explain the relation between pressure and volume using molecular theory 4. Explain how gases produce pressure on the walls of their containers 5. Explain how temperature increases the pressure of gases

1. What is the relation between gas pressure and volume at constant temperature? The relation is an inverse one. When volume is decreased, pressure is increased and when volume is increased pressure is decreased. This can be written as V1P1=V2P2=constant

2. State Boyle's law. The volume of a fixed mass of a gas is inversely proportional to the pressure, if the temperature is constant

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3. Explain the relation between pressure and volume using molecular theory?

If the volume of the gas is decreased, the molecules are crowded in a smaller space and the area of the walls decreases then the number of bombardments per second on the walls increases and the gas pressure increase.

4. Explain how gases produce pressure on the walls of their containers? Gas molecules are in a state of continuous motion in all directions, and they are constantly bombarding the walls of the container. When the molecules bounce off the walls, they produce an outward force on the walls which causes the outward pressure of the gas on the walls of the container.

5. Explain how temperature increases the pressure of gases? When the temperature rises, the gas molecules gain kinetic energy and move faster and thus strike the container wall more frequently and with greater force. Therefore, the total force exerted per unit area of the walls is greater and the pressure increase.

6.

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Thermal Properties

(a) Thermal Expansion of Solids, liquids and gases

2 Thermal Physics Where to go! 2.2 Thermal Properties E122

A Thermal Expansion of solids, liquids and gases E126, EE130, E132, E134

Core-1 Describe qualitatively the thermal expansion of solids, liquids and gases E126, EE130, E132, E134

Core-2 Identify and explain some of the everyday applications and consequences of thermal expansion.

Bimetal, Thermostat E130

Core-3 Describe qualitatively the effect of a change of temperature on the volume of a gas at a constant pressure. E135

Sup-1 Show an appreciation of the relative order of magnitude of the expansion of solids, liquids and gases E126, E127, E128

Expansion Objectives: The student should be able to …

1. Explain what is meant be expansion 2. Explain why things expand 3. Explain what happen when solids are heated 4. Explain what happen when solids are cooled 5. List the factors which affect the expansion of solids 6. Compare between the expansivity of solids, liquids, and gases. 7. List four real-life problems due to expansion of materials. 8. Explain what us meant by bimetal strip? 9. Describe the action of a bimetal? 10. Explain how to build a fire alarm using bimetals. 11. Explain what does a thermostat mean? 12. Explain the structure and the action of thermostat? 13. List some applications to thermostat in industry

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1. What do you see in these pictures?

2. What is meant be expansion? Is the difference between the original size of an object and its size when its cooled or heated.

3. Why things expand?

When a solid is heated its particles vibrate more rapidly. As a result they collide and push each other further apart.

Expansion of solids 4. Explain what happen when solids are heated?

When a solid is heated, its molecules gain kinetic energy and vibrate more vigorously. As the vibration become larger, the molecules are pushed further apart and the solid expands slightly in all directions.

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5. Explain what happen when solids are cooled? When a solid is cooled, its molecules lose kinetic energy and have less vibration. As the vibration become lower, the molecules are pulled closer and the solid contracts slightly in all directions.

6. List the factors which affect the expansion of solids? Original length (direct), temperature (direct), material type

7. Compare between the expansivity of solids, liquids, and gases. Solids in general have the smallest expansivity while gases have the greatest expansivity and liquids lie in between.

8. List four real-life problems due to expansion of materials.

On a hot day concrete runway sections in airport expands and this cause cracking. To solve this problem we leave small gabs between sections.

On a hot day concrete bridges expand. To solve this problem, we leave small gab at one end and support the other end with rollers.

Telephone wire contract on cold days. To solve this problem, we leave wires slack so that they are free to change length.

On a hot day railway lines expand. To solve this problem, gaps are left between sections of railway lines to avoid damage of the rails as they expand in hot weather.

9. What us meant by bimetal strip? A bimetal strip is a two-thin strips of different metals welded together.

10. Describe the action of a bimetal?

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When the bimetal strip is heated, the brass expands more than invar and this makes the strip bends with brass on the outside of the curve.

If the strip is cooled, instead of heated, it would bend the opposite way.

11. Explain how to build a fire alarm using bimetals.

12. What does a thermostat mean? A thermostat is temperature operated electrical switch that uses the expansion properties of a bimetal strip.

13. Explain the structure and the action of thermostat?

The figure shown to the right shows a thermostat. The control knob sets the temperature at which the switch will turn off. The bimetal strip provides the expansion and contraction which results closing or opening the electrical circuit of the system under control.

When the bimetal strip is heated it curves and breaks contact then the temperature reaches a certain value. Thus, switching off the current to the system under control.

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14. List some applications to thermostat in industry

1. electric irons 2. fish tanks 3. home heating/cooling

systems 4. Ovens, refrigerators, 5. fire alarms, car flashers

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Expansion of liquids Objectives: The student should be able to …

1. Explain what happen when liquids are heated 2. Explain what happen when liquids are cooled 3. List the factors that affect the expansion of liquids 4. Compare between the expansivity of liquids and solids 5. Explain why when heating a liquid, its level initially decreases and then it increases to

become larger than the original level? 6. List some applications that use the expansion of liquids 7. Explain the effect temperature on volume of water 8. Explain when water has its minimum volume or higher density 9. Explain the effect temperature on density of water 10. Explain why filled bottles of water when placed in a freezer may burst when water is

frozen 11. Explain why ice floats on water 12. Explain why the surface of a lake freezes while the deepest water stays at 4C

1. What do you see in the picture below?

2. Explain what happen when liquids are heated? When a liquid is heated, its molecules gain kinetic energy and vibrate more vigorously. As the vibration become larger, the molecules are pushed further apart and the liquid expands slightly in all directions.

3. Explain what happen when liquids are cooled? When a solid is cooled, its molecules lose kinetic energy and have less vibration. As the vibration become lower, the molecules are pulled closer and the solid contracts slightly in all directions.

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4. List the factors that affect the expansion of liquids? Temperature (direct), liquid volume (direct), liquid type

5. Compare between the expansivity of liquids and solids? Expansivity of liquids is much greater than the expansivity of solids.

6. Explain why when heating a liquid, its level initially decreases and then it increases to become larger than the original level? The liquid level drops due to the expansion of its container, which initially absorbed all the heat. After a while, the heat reaches the liquid it compensates for the expansion of the container and rises much more than the original level.

7. List some applications that uses the expansion of liquids?

1. Thermometers

2. The valve shown below operates based on the expansion of the oil. As the room warms of the oil in the valve expands and pushes the piston down. This shuts off the flow of hot water. When the temperature drops the valve opens again.

8. Explain the effect temperature on volume of water? The water volume decreases from 0ºC-4ºC. After 4ºC, the volume of water increases gradually.

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9. When water has its minimum volume or higher density? Water has its minimum volume at 4ºC.

10. Explain the effect temperature on density of water? The water density increases from 0ºC to 4ºC. After 4ºC, the density of water decreases gradually.

11. Explain why filled bottles of water when placed in a freezer may burst when water is frozen? When water freezes it changes to ice and its volume increases by about 9%. Since bottle is filled, then there is no space left for the increased 9%, thus a high pressure starts to builds up against the bottle walls from inside. This high pressure burst the bottle.

12. Explain why ice floats on water? When water freezes it changes to ice and its volume increases by about 9%. The increase in volume means that the ice is less dense than water beneath it and it will floats.

13. Explain why the surface of a lake freezes while the deepest water stays at 4C?

When the weather gets cold, the temperature of water at the surface drops down and it becomes more dense than the water underneath. The dense water starts to sink and warmer water is pushed up. The water will keep circulating until the temperature of all water in lake become 4C. When the water temperature at the surface drops below 4C its volume starts to increase and its density starts to decrease. At this stage, the water is less dense than the water underneath and it stays on the surface. In time, ice forms on the surface and the water temperature at the bottom of the lake will remain at 4C. Thus, fish can survive a severe winter by staying in the deep warm water.

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Expansion of gases (see also pressure changes )


1. Compare the expansion of gases to that of solids and liquids 2. Explain the effect of temperature on gas volume when pressure is constant 3. Explain the effect of temperature on gas pressure when volume is constant 4. Explain an experiment to show the effect of temperature on gas pressure 5. State the statement of "Charlie's law" 6. State the statement of the pressure law 7. State the statement of the Boyle's law 8. State the general law of gases?

1. Compare the expansion of gases to that of solids and liquids? The expansion of gases is much more larger than that of solids or liquids under the same rise in temperature.

2. Explain the effect of temperature on gas volume when pressure is constant? When pressure is constant, the volume of a gas is directly proportional to the Kelvin temperature (Charlie's Law). When the temperature of a gas is increased, the molecules move faster and the collisions become more violent thus they spread away from each other causing the volume to increase.

3. Explain the effect of temperature on gas pressure when volume is constant?

When volume is constant, the pressure of a gas is directly proportional to the Kelvin temperature (Pressure Law). In gas, molecules are always on the move. They travel fast, hitting each other and the sides of their container. If the temperature is increased, the molecules move faster and the collisions become more violent thus the pressure increase.

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4. Explain an experiment to show the effect of temperature on gas pressure?

5. What is the statement of "Charlie's law"? When pressure is constant, the volume of a gas is directly proportional to the Kelvin temperature. Mathematically: V1/T1=V2/T2

6. What is the statement of the pressure law? When volume is constant, the pressure of a gas is directly proportional to the Kelvin temperature. Mathematically: T1/P1=T2/P2

7. What is the statement of the Boyle's law? When temperature is constant, the volume of a fixed max of a gas is inversely proportional to the pressure Mathematically: P1V1=P2V2

8. What is the general law of gases?

When gas parameters change from P1,V1, and T1 to P2, V2, T2 then P1V1/T1=P2V2/T2

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(b) Measurement of Temperature

2 Thermal Physics Where to go?

2.2 Thermal Properties E122

B Measurement of temperature E122

Core-1 Appreciate how a physical property which varies with temperature may be used for the measurements of temperature and state examples of such properties.

E122- E125

Core-2 Recognize the need for identify a fixed point E123 Core-3 Describe the structure and action of liquid-in-glass thermometers E124 Sup-1 Demonstrate understanding of sensitivity, range, and linearity E124 Sup-2 Apply a given property to the measurement of temperature E125

Sup-3 Describe the structure and action of a thermocouple and show an understanding of its use for measuring high temperature and those which vary rapidly

E125

Objectives: The student should be able to

1. Define temperature? 2. List the physical properties that are used to measure temperatures 3. List the types of temperature meters 4. List liquid-in-glass thermometers types 5. Describe the structure of liquid-in-glass thermometers 6. Explain how liquid-in-glass thermometers operate 7. List the basic properties of thermometers 8. Define sensitivity, range, and uniformity 9. Explain how to increase the sensitivity of a thermometer 10. Explain how a decrease in tube diameter of a liquid-in-glass thermometer will increase

sensitivity? 11. Explain how an increase in volume of a liquid-in-glass thermometer will increase

sensitivity? 12. Explain how to increase the range of a thermometer

Explain how a decrease in volume bulb of a liquid-in-glass thermometer will increase range?

13. Explain how an increase in tube diameter of a liquid-in-glass thermometer will increase range

14. List the three basic scales for temperature measurements 15. Define the two fixed points in Celsius scale 16. Define "lower fixed point" and "upper fixed point" 17. Describe the Kelvin scale 18. Define "absolute-zero" temperature 19. Explain the relation between Kelvin temperature and Celsius temperature 20. List four advantages of mercury as a liquid 21. List three disadvantages of mercury 22. Describe alcohol thermometer 23. List two advantages of Alcohol 24. List three disadvantages of alcohol 25. Explain why a clinical thermometer has a narrow constriction just above its bulb 26. List the properties of a clinical-thermometer

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27. Describe the structure of a thermocouple meter 28. Describe the operation of a thermocouple meter 29. List the advantages of a thermocouple thermometer 30. List three precautions a person must take when measuring temperature 31. Explain why Mercury or alcohol thermometers are not suitable to measure

temperatures deep inside a furnace

Temperatures 1. Define temperature?

Temperature is a measure of the average kinetic energy possessed by each molecule of the substance.

2. What are the physical properties that are used to measure temperatures? 1. Expansion of materials

1. Liquids: mercury, alcohol 2. Solids: Thermocouple

2. Electromotive force: Thermocouple 3. Change in electrical resistance

Thermometers

1. List the types of temperature meters? 1. Liquid-based thermometers 2. Solid-based thermometers

2. List liquid-in-glass thermometers?

1. Mercury thermometer 2. Alcohol thermometer 3. Clinical thermometer

3. Describe the structure of liquid-in-glass thermometers?

1- Glass tube 2-Bulb 3-Liquid 4-Thread 5-Scale

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4. Explain how liquid-in-glass thermometers operate? The bulb of thermometer contains liquid (e.g. mercury, alcohol) which expands when temperature rises and pushes a thread of liquid along the scale where temperature can be read.

5. List the basic properties of thermometers? sensitivity, range, and uniformity

6. What is meant by the following terms: sensitivity, range, and uniformity? sensitivity: is the ability of a thermometer to detect small changes in temperature. range: is the range of temperatures which can be measured by the thermometer linearity (uniformity): the expansion of the liquid should be linear (uniform, the same) for all different temperatures measured.

7. How do we increase the sensitivity of a thermometer? 1- increase in the volume of the bulb 2- decreases the diameter of the tube (bore)

8. Explain how a decrease in tube diameter of a liquid-in-glass thermometer will increase sensitivity? Because an increase in volume of the liquid in a narrow diameter will make the thread move a long way up the tube (higher expansion). Thus a small change in temperature can be reflected easily on the scale.

9. Explain how an increase in volume of a liquid-in-glass thermometer will increase sensitivity? Because the expansion in liquid volume is directly proportional to the original volume of the liquid. Thus, a small change in temperature can be reflected easily.

10. How do we increase the range of a thermometer? 1- decrease in the volume of the bulb 2- increases the diameter of the tube (bore)

11. Explain how a smaller bulb of a liquid-in-glass thermometer will increase range? Since the expansion is directly proportional to the original volume of the liquid, a smaller bulb means less volume, which implies more temperature is needed to increase volume expansion to be reflected easily on scale. Thus, the range is increased.

12. Explain how an increase in tube diameter of a liquid-in-glass thermometer will increase range? Because a wider diameter will result in less expansion. Hence, large temperature is needed to increase the expansion. Thus, the range is increased.

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Celsius Scale 1. List the three basic scales for temperature measurements?

Celsius Scale Kelvin Scale

2. What are the two fixed points in Celsius scale? 1- The lower fixed point 2- The upper fixed point

3. What is meant be "lower fixed point" and "upper fixed point"? 1. The lower fixed point is the temperature of pure melting ice. This is called the 0°C. 2. The upper fixed point is the temperature of steam above pure boiling water under

standard atmospheric pressure. It is call the 100°C.

Kelvin Scale

1. Describe the Kelvin scale? The Kelvin scale is the same as the Celsius scale except it starts from absolute zero. The a one degree Kelvin is equal to one-degree Celsius.

2. What is meant by "absolute-zero" temperature? Absolute-zero is the lowest temperature in the universe and at this temperature the molecules of a substance have the minimum possible energy. It occurs at -273°C.

3. What is the relation between Kelvin temperature and Celsius temperature? TK=TC+273 where TK is temperature in Kelvin and TC is temperature in Celsius.

Mercury Thermometers 1. List four advantages of mercury as a liquid?

1. Does not stick to the sides of tube 2. thread easy to use 3. conducts heat well 4. responds quickly to changes in temperature

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2. List three disadvantages of mercury? 1. Freezes at -39°C. Not suitable for low temperatures 2. Poisonous 3. Expensive

Alcohol Thermometer 1. Describe alcohol thermometer.

2. List two advantages of Alcohol? 1. Freezes at -115°C. Suitable for low temperature measurements. 2. Has expansion more than mercury.

3. List three disadvantages of alcohol

1. Has to be colored to be seen easily 2. Clings (sticks) to the sides of tube 3. Thread has tendency to break

Clinical Thermometers 1. Why a clinical thermometer has a narrow constriction just above its bulb

to stop the mercury thread from falling back into the bulb when the thermometer cools down

2. List the properties of a clinical-thermometer. 1. Is used to measure the temperature of human body 2. Its range is 35°C to 43°C 3. Has a narrow constriction just above its bulb

3.

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Thermocouple Thermometers 1. Describe the structure of a thermocouple meter?

It is made by joining two different metals assembled (e.g. copper & iron) into two junctions. One junction is placed in pure melting ice (Cold junction) and the other junction is placed in the hot object (called hot junction).

2. Describe the operation of a thermocouple meter? When there a difference in temperature between the hot and cold junctions an electric current is generated. This current is used to deflect a galvanometer which is calibrated to temperature degrees.

3. List the advantages of a thermocouple thermometer? 1. Easy to read by using a pointer or a digital display. 2. Scale can be placed a way from the temperature detector 3. Can be used automatic electrical control circuits. 4. Wide range of temperature -200°C to 1600°C 5. It has has a small thermal capacity and is used to measure rapidly changing

temperatures.

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(c) Thermal Capacity

2 Thermal Physics Where to go! 2.2 Thermal Properties E122

C Thermal Capacity E144

Core-1 Relate a rise in temperature of a body to an increase in internal energy (random thermal energy) E144, E140

Core-2 Show an understanding to the term thermal capacity. E145

Sup-1 Describe an experiment to measure the specific heat capacity of a substance E147


1. Define melting point 2. Define thermal energy 3. Explain what happen to the internal energy when a body

is heated 4. Explain the relation between the rise in temperature and

the amount of heat gained 5. List the factors that affect the thermal energy 6. Define specific heat capacity 7. Describe the specific heat of water 8. Define thermal capacity of a body 9. Why water is used in central heating systems 10. Explain the process of heat exchange 11. State the law of conservation of energy 12. Describe an experiment to measure the specific heat

capacity of a substance

1. What do you see in this picture?

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2. What is meant by thermal energy? Thermal energy is the energy that a substance contains due to the vibration of its atoms. If a substance is heated, its atoms vibrate faster. This may show a rise in temperature or may change to a state with higher energy.

3. Explain what happen to the internal energy when the body is heated? When a body is heated, its internal energy will increase because its molecules will move faster.

4. What is the relation between the rise in temperature and the amount of heat gained by an object? The amount of heat gained by an object is given by H=m·c·(T2-T1). Where

1. (T2-T1) rise in temperature "C or K". 2. "m" the mass of the body "Kg" 3. "c" Specific heat capacity of material in J/KgK or J/KgC.

5. What are the factors that affects the thermal energy?

1. Temperature rise 2. The mass of the body 3. Specific heat capacity of material

6. What is meant by specific heat capacity?

Specific heat capacity is the amount of heat energy required to raise the temperature of a "1" Kg of the substance by "1" degree Celsius. Its unit is given as J/KgK or J/KgC.

7. Describe the specific heat of water? The specific heat of water is high (4200 J/Kg).

8. Why creatures can to resist a high change in temperature? Because they contain a large amount of water.

9. What is meant by thermal capacity of a body? Thermal capacity of a body is the amount of heat energy required to raise the temperature of the whole body by one Celsius degree.

10. Why water is used in central heating systems? Water is used in indoor heating systems to store and carry heat energy to heat radiators because it has a very large heat capacity.

11. Explain the process of heat exchange? When two objects at different temperatures are mixed they exchange energy until they reach a common temperature.

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12. State the law of conservation of energy? The amount of heat gained is equal to the amount of heat lost.

13.

Skills 1. A piece of "Al" of mass 0.5 kg is heated to a 100ºC and then placed in a 0.4 Kg of water

at 10ºC. If the final temperature of the mixture is 30ºC. What is the specific heat of Aluminum if the specific heat of water is 4200J/C. Heat gained by water=Heat Lost by Aluminum mw·cw·(x-Tw)=mAl·cAl·(TA1-x) 0.4*4200*(30-10)=0.5*cAl*(100-30) cAl=960 J/KgC

2. A tank holding 60 Kg of water is heated by a 3 KW electric heater. If the specific heat of water is 4200J/KgK estimate the time for the temperature to rise from 20C to 70C.

Heat Lost by heater=Heat gained water Electrical Energy= Heat gained water Power*time= mw*cw*(x-Tw) 3000*t=60 Kg* 4300 * (70-20) t=4200 seconds= 70 minutes

3. Describe an experiment to measure the specific heat capacity of a substance. See page E147 and “Lab manual”

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(d) Melting and Boiling 2 Thermal Physics Where to go?

2.2 Thermal Properties E122

D Melting and Boiling E148, E158

Core-1 Describe melting and boiling in terms of energy input without a change in temperature E148, E150

Core-2 State the meaning of melting point and boiling point E148, E150 Core-3 Describe condensation and solidification E159 Sup-1 Distinguish between boiling and evaporation E158 Sup-2 Use the term latent heat and give a molecular interpretation of latent heat E148 Sup-3 Describe an experiment to measure specific latent heats for steam and for ice E54


1. Define melting point, freezing point and boiling point 2. List factors that affect the melting point and boiling points 3. State the difference between melting and freezing 4. Explain “substances that have defined freezing points” 5. Explain how one can we lower the melting point of ice 6. Locate melting point on cooling curve 7. Define "latent heat of fusion" 8. Explain why it is called "Latent heat" 9. Explain why latent heat of fusion does not increase the object temperature by the

molecular theory? 10. Define "Specific latent heat of fusion Lf" 11. Calculate the amount of energy needed to change "m" kg from solid state to liquid state. 12. List the difference between boiling and evaporation. 13. Define "Latent heat of vaporization" 14. Explain why the temperature remains constant until all the liquid changes to vapor 15. Define specific heat of vaporization 16. Calculate the amount of heat absorbed during vaporization 17. Describe an experiment to measure the specific latent heat of ice. 18. Describe an experiment to measure the specific latent heat of steam. 19.

Melting and Freezing Points 1. What is meant by melting point?

When a pure solid is heated, its temperature rises until it reaches the "milting point" where it remains constant until all solid changes to liquid.

2. List factors that affect the melting point and boiling points 1. High Pressure reduce melting point 2. Adding impurities to a substance changes its melting point

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3. What is the difference between melting and freezing? The melting point is the same as the freezing point. An object absorbs heat to become

4. What are the types of substances that have defined freezing points? Pure substances have fixed freezing points like pure water.

5. How can we lower the melting point of ice? 1. By increasing the pressure on the ice 2. By adding impurities to the ice.

1. For example salt reduces the temperature of melting ice to -18C 2. Adding anti-freeze to car radiators in winter 3. Spreading salt on icy roads

Latten Heat 1. What is meant by "latent heat of fusion"?

Latent heat of fusion is the heat energy needed to change an abject from a solid state to a liquid state. Latent heat of fusion is the energy needed to overcome the intermolecular force to separate the molecules during the melting process.

2. Why it is called "Latent heat"? Because it does not raise the temperature during absorption.

3. Explain why latent heat of fusion does not increase the object temperature by the molecular theory? The latent heat if fusion is the energy needed to overcome the intermolecular force to separate the molecules during the melting process. The absorbed energy causes the molecules to move further apart increasing their potential energy rather than kinetic energy. So, the kinetic energy does not change and so the temperature stays the same.

4. What is meant by "Specific latent heat of fusion Lf"? Specific latent heat of fusion Lf is the thermal energy required to change 1Kg of a solid to a liquid without a change in temperature.

5. What is the amount of energy needed to change "m" kg from solid state to liquid state? E=m Lf where "m": mass in Kg "Lf" is the latent heat of fusion

6. How much heat is needed to change 0.2 kg of ice into water? E=m Lf =0.2*334000 =66800J.

7. What is the difference between boiling and evaporation? 1. Boiling occurs at a definite temperature (the boiling point), but evaporation occurs at

all temperatures. 2. Boiling occurs within all the volume of the liquid, but evaporation occurs at the

surface of the liquid. 3. In boiling, bubbles appear within the liquid, but there are no bubbles in evaporation.

8. Describe an experiment to measure the specific latent heat of ice.

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1. Place an electric heater in the melting ice packed in a funnel. 2. Switch on the heater and turn on the stop-watch and collect the water from melting

the ice fir several minutes 3. Switch off the heater and turn off the stop-watch and then find the mass "m" of

collected water 4. Apply the conservation of energy. The energy supplied by the heater equals the heat

used to melt the ice 5. P*t=m*Lf from which Lf=P*t/m where Lf is measured in "J/Kg" 6. In this experiment where it is done at room temperature, ice will absorb heat from

the surroundings and the collected water becomes greater than it should and thus the value of Lf obtained is smaller than the true value.

9. Describe an experiment to measure the specific latent heat of steam. 1. When the water is boiling take a reading for the mass by balance and recorded as

"m1" and start stop-watch. 2. After several minutes, stop the stop-watch and take another reading for the mass as

"m2". 3. The difference between the two masses is the mass of the water which has vaporized

(m=m2-m1). 4. The energy supplied by the heater equals to the energy used to change water into

steam Pt=n Lv, from which Lv=P*t/m in (J/Kg).

5. Some heat is lost to the surroundings and measured "m" is smaller than it should, thus the value of Lv obtained is greater than the true value.

10.

Boiling Point 1. What is meant by boiling point?

When a liquid is heated, its temperature rises until it reaches the "boiling point" where it remains constant until all the liquid changes to vapor.

2. What is meant by the "Latent heat of vaporization"? Is the heat energy absorbed during boiling and changes liquid to vapor.

3. Explain why the temperature remains constant until all the liquid changes to vapor? The latent heat of vaporization is the energy required to force the molecules far a part from each other to change the liquid into vapor. The molecules travel freely in random directions and their average kinetic energy dies not change which keeps the temperature constant during the change.

4. What is meant by specific heat of vaporization? It is the heat energy required to change one kilogram of the liquid into vapor state without any change in its temperature.

5. What is the amount of heat absorbed during vaporization? E=mLv

6.

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Transfer of Thermal Energy

(a) Conduction

2 Thermal Physics Where to go! 2.3 Transfer of Thermal Energy E140, E142, E208

A Conduction E1.8, E140

Core-1 Describe experiments to demonstrate the properties of good and bad conductors of heat E140

Sup-1 Give simple molecular account of the heat transfer in solids E140


1. Explain how heat is flows between two bodies 2. List three ways for transferring heat from on place to another 3. Explain is meant by conduction 4. Explain how heat is transferred by conduction 5. List some good conductors of heat 6. List some poor conductors (insulators) of heat 7. Explain an experiment to demonstrate the properties of good and bad conductors of

heat

1. Explain how heat is flows between two bodies? Heat flows from high temperature to low temperature

2. List three ways for transferring heat from on place to another? 1. Conduction 2. Convection 3. Radiation

3. What is meant by conduction?

Conduction is the process of transferring heat by the vibration of the object molecules

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4. How heat is transferred by conduction? When we heat one end of a metal bar, the particles at this end will vibrate faster hitting adjacent particles and make them vibrate faster. In time, this process continues until all the particles at the other end vibrate faster.

5. List some good conductors of heat. All metals are good conductors of heat. Gold, Silver, Copper, Iron, lead, zinc, steel.

6. List some poor conductors (insulators) of heat. All gases, glass, plastic, rubber, wood, polystyrene and materials with air trapped in the: aerated concrete, wool, glass wool, plastic foam, expanded polystyrene.

7. Explain an experiment to demonstrate the properties of good and bad conductors of heat

Bring different metals (for example steel, iron, aluminum, copper as shown) in the form of rods of equal size and coat each one with a thin layer of wax. Place the metals in a container that contains heated water at 100C and leave them for about 10 minutes. The rod that has the grater length of melted wax is considered the best conductor of heat.

8.

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(b) Convection


B Convection E4.9, E142

Core-1 Relate convection in fluids to density changes and describe experiments to illustrate convection

E142


1. Explain what is convection 2. Describe convection in air 3. Explain an experiment to show convection in air 4. Explain an experiment to show convection in water 5. Explain why warm fluid rises 6. Explain convection of air by heat radiators 7. Explain convection of air in refrigerators 8. Explain convection of water in hot-water supply system 9. Explain why the freezer compartment in a refrigerator is placed at the top 10. Explain why a refrigerator does not work properly if the food is too tightly packed

inside. 11. Explain why a radiator quickly warms all the air in a room, even though air is a

very poor conductor of heat. 12. Explain why warm water rises when surrounded by cooler water. 13. Explain how can we reduce heat lost due to convection?

1. What is convection? Convection is a circulating current in a fluid (liquid or gas).

2. Describe convection in air. In air, warm air rises and cool air moves in to take its place

3. Explain an experiment to show convection in air. Hot air rises above the candle. Cooler air flows in to replace hot air. The smoke from the burning straw shows the current of air.

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4. Explain an experiment to show convection in water. Hot water rises above the Bunsen flame. Cooler water flows in to replace it. Potassium permanganate crystals color the water so that one can see the current.

5. Why warm fluid rises? When the fluid is heated it expands. This makes it less dense because the mass takes up a larger volume. So being less dense, the warm air floats upwards through the denser, cooler air a round it.

6. Explain convection of air by heat radiators. Most of the heat from a radiator is circulated by convection. Warm air around the radiator rises above the radiator and cooler air replaces it. The cooler air gets heated by the radiator and it rises and cooler air moves in to replace it. This process continues until all the air in the room has the same temperature.

7. Explain convection of air in refrigerators. In a refrigerator, the freezer cools the air around it. As a result, the cooled air moves down and hot air at the bottom of the refrigerator moves up. This process continues until all the air in the refrigerator has the same temperature.

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8. Explain convection of water in hot-water supply system.

From the figure shown, water is heated in the boiler. It rises to the storage tank. Cooler water flows in to replace it. It too is heated. In time, a supply of hot water collects in the tank from the top down. The header tank provides the pressure to push hot water out of the raps.

9. Explain why the freezer compartment in a refrigerator is placed at the top. Because warm always rises and cooler air sinks. When warm air rises, it enters the freezer compartment and gets cooler and as a result it sinks and a new hot air rises. In time, all the air will be cooled.

10. Explain why a refrigerator does not work properly if the food is too tightly packed inside. Because a tightly packed food will prevent the circulation of warm and cool air.

11. Explain why a radiator quickly warms all the air in a room, even though air is a very poor conductor of heat. Because heat is carried due to the air circulations by convection rather than by conduction.

12. Explain why warm water rises when surrounded by cooler water. Because it density is less than density of the cooler water surrounding it.

13. Explain how can we reduce heat lost due to convection? This can be done by preventing air circulations. For example, when we cover hot tea we prevent air circulations and thus prevent convection to take place.

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(c) Radiation


C Radiation E208 Core-1 Identify infra-red radiation as a part of the electromagnetic spectrum E208

Sup-1 Describe experiments to show the properties of good and bad emitters and good and bad absorbers of infra-red radiation E209


1. Explain what is meant by heat radiation 2. Explain how heat reaches us from the Sun 3. Explain the relation between the heat in an object and and the wavelength of emitted

EM 4. Explain what happens when heat radiations fall on an object 5. Explain how heat radiation can be detected? 6. Explain what is meant by "bad emitters", "bad absorbers", "good emitters" and

"good absorbers" 7. Explain why people wear dark clothes in winter and white clothes in summer 8. Explain why roofs of petrol tanks are painted in shiny aluminum 9. Explain why vacuum flasks are made if double-walled glass vessels with vacuum

between the walls and the walls are silvered? 10. Explain why Greenhouses are made of glass walled rooms to keep warm climate in cold

nights 11. Explain why cloudy nights remain warm 12. Explain an experiment to show that black surfaces are good absorbers of heat

radiation and shiny surfaces are good reflectors of heat radiations.

1. What is meant by heat radiation? Heat radiation is a form of electromagnetic waves called "infra-red" waves?

2. How heat reaches us from the Sun? By the heat radiations emitted from the sun which can travel in vacuum.

3. What is the relation between the heat in an object and and the wavelength of emitted EM? The hotter the object the shorted the wavelength.

4. What happens when heat radiations fall on an object? Part of the radiation is absorbed and the other part is reflected

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5. How heat radiation can be detected? They can be detected using a " thermopile" and a "blackened bulb meter"

6. What is meant by "bad emitters", "bad absorbers", "good emitters" and "good absorbers"? "bad emitters", "bad absorbers" are objects that reflect heat radiation "good emitters" and "good absorbers" are objects that absorb heat radiation

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7. Why people wear dark clothes in winter and white clothes in summer? People wear dark clothes in winter to keep warm because dark cloths are good absorbers of heat radiations. On the other hand, people wear white clothes in summer to keep cool because white cloths are good reflectors of heat radiations.

8. Why roofs of petrol tanks are painted in shiny aluminum? Because a shiny aluminum will reflect heat radiation and thus prevent overheating petrol which might generate to much gases that may lead to an explosion or a fire.

9. Why vacuum flasks are made if double-walled glass vessels with vacuum between the walls and the walls are silvered? They are made of double-walled glass with vacuum in between to prevent heat transfer from or to the liquid inside them. They are silvered because a silvered surface reflects heat

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radiation.

10. Why Greenhouses are made of glass walled rooms to keep warm climate in cold

nights?

Because glass will prevent convection between the air trapped in rooms and the air outside rooms at the same time it allows heat radiation to enter from glass which supply heat to the insides of the room. During cool night, the heat energy gained from radiation is emitted back inside the house which keeps warm during the night.

11. Why cloudy nights remain warm? When air rises up it cools down and becomes more dense. Thus it sinks down until it reaches the Earth surface which in return cools the surface. When cloud are present, they prevent cool air to sink and reach the surface. Also, the reflect heat radiations and prevent them from reaching ground.

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12. Explain an experiment to show that black surfaces are good absorbers of heat radiation and shiny surfaces are good reflectors of heat radiations.

13.

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(d) Consequences of Energy Transfer

2 Thermal Physics Where to go!

2.3 Transfer of Thermal Energy E4.8, E4.9,E5.12

D Consequences of Energy Transfer E4.8, E4.9,E5.12

Core-1 Identify and explain some of the everyday applications and consequences of conduction, convention and radiation E4.8, E4.9,E5.12


1. Explain why people wear dark clothes in winter and white clothes in summer 2. Explain why roofs of petrol tanks are painted in shiny aluminum 3. Explain why vacuum flasks are made if double-walled glass vessels with vacuum

between the walls and the walls are silvered? 4. Explain why Greenhouses are made of glass walled rooms to keep warm climate in cold

nights 5. Explain why cloudy nights remain warm 6. Explain why the freezer compartment in a refrigerator is placed at the top 7. Explain why a refrigerator does not work properly if the food is too tightly packed

inside. 8. Explain why a radiator quickly warms all the air in a room, even though air is a very

poor conductor of heat. 9. Explain why warm water rises when surrounded by cooler water.

See: conduction, convection and radiations

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Properties of Waves, Including Sound and Light

General wave properties 3 Properties of Waves Where to go!

3.1 General wave properties E5.9, E195

Core-1 Describe what is meant by wave motion as illustrated by vibration in ropes, springs, and by experiments using water waves. E195

Core-2 Use the term wave front E196 Core-3 give the meaning of speed, frequency, wavelength and amplitude E196

Core-4 Distinguish between transverse waves and longitudinal waves and give suitable examples. E195, E210

Core-5 Describe the use of water waves to show (i) Reflection at a plane surface (ii) refraction at a plane surface. E197, E198, E199

Sup-1 give a meaning to the term wave front E196 Sup-2 recall and use the equation v=fL E196 Sup-3 interpret reflection, refraction, diffraction E197, E198, E199


1. List are the three types of waves 2. Explain what is meant by transverse waves 3. Explain what is meant by Longitudinal waves 4. Explain what is meant by Surface waves 5. Explain what is a pulse 6. Explain what is a wave? 7. Explain what is meant by "wave period" 8. Explain what is meant by "wave frequency" 9. Explain what is meant by "wave amplitude" 10. Explain what is meant by "wave length" 11. Explain what is meant by "wave phase" 12. Explain what is meant by "wave front" 13. Explain what is meant by ray 14. Explain how the speed of a wave is related to its length and frequency 15. Explain that wave velocity does not depend on frequency or wavelength of the wave 16. Calculate the period of a wave? 17. Use c=f λλλλ to calculate frequency or wavelength? 18. Explain what happens to a wave when it moves form one medium to another medium? 19. Explain what is meant by Collision of waves 20. Explain what is meant by a constructive interference 21. Explain what is meant by Destructive interference 22. Explain what is meant by reflection of waves? 23. Explain what is meant by refraction 24. Explain what is meant by diffraction 25. Explain what happen to the following wave properties if it undergoes reflection,

refraction and diffraction?

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1. What are the three types of waves?

1. Mechanical waves require a material medium to travel (air, water, ropes). These waves are divided into three different types: transverse, Longitudinal, and surface waves.

2. Electromagnetic waves do not require a medium to travel (light, radio). 3. Matter waves are produced by electrons and particles. 4.

2. What is meant by transverse waves? transverse waves cause the medium to move perpendicular to the direction of the wave.

3. What is meant by Longitudinal waves ? Longitudinal waves cause the medium to move parallel to the direction of the wave.

4. What is meant by Surface waves? Surface waves are both transverse waves and longitudinal waves mixed in one medium.

5. What is a pulse? Pulse is a single vibration. By moving a rope once, a single vibration is produced. Click on the image to produce a pulse.

6. What is a wave?

A wave is a series of pulses. By moving a rope regularly up and down, a traveling or periodic wave is produced.

7. What is meant by "wave period"? Any point on a transverse wave moves up and down in a repeating pattern. The shortest time that a point takes to return to the initial position (one vibration) is called period, T. In this example, every vibration is marked with a short pause.

8. What is meant by "wave frequency"? The number of vibrations per second is called frequency and is measured in hertz (Hz). Here's the equation for frequency: f = 1 / T

9. What is meant by "wave amplitude"? The amplitude of a wave is the distance from a crest to where the wave is at equilibrium. The amplitude is used to measure the energy transferred by the wave. The bigger the distance, the greater the energy transferred.

10. What is meant by "wave length"? The wavelength is the distance between two crests or two troughs.

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11. What is meant by "wave phase"? Phase is used to describe the starting points of two waves. If their crests start at the same time they are called in phase if not they are called out of phase. If the difference between the two crests is 180 degrees they are called completely out of phase.

12. What is meant by "wave front"?

Wave front is a line or a surface perpendicular to the wave direction and on which all disturbances at every point have the same phase.

13. What does ray mean? A ray is a line that represents the direction of travel of a wave and it is always at right angle to the wave front.

14. How the speed of a wave is related to its length and frequency? By knowing the frequency of a wave and its wavelength, we can find its velocity. Here is the equation for the velocity of a wave:

15. Does the velocity of a wave depend on frequency or wave length of the wave? No it does not. The velocity of a wave is only affected by the properties of the medium. It is not possible to increase the speed of a wave by increasing its wavelength. By doing this, the number of vibrations per second decreases and therefore the velocity remains the same.

16. A radio wave has a frequency of 93.9 MHz (93.9 * 106 Hz). What is its period? f = 93.9 * 106 Hz f = 1 / T T = 1 / f T = 1 / 93.9 x 106 Hz

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T = 1.06 x 10-8 s

17. If the velocity of a radio wave is 300 000 000 m/s (light speed) and its wavelength is 3.0 m, what is the frequency of the wave? f=c/λ=300 000 000/3.0=100,000,000 Hz

18. What happens to a wave when it moves form one medium to another medium? Once a wave (incident wave) has reached the end of a medium, part of the energy is transferred to the medium that is immediately next to it (transmitted wave) and part is reflected backward (reflected wave).

The energy transferred depends on the difference between the mediums. If there is a significant difference, almost all the energy will be reflected. If the mediums are similar, most of the energy will be transferred. However, the reflected waves will be inverted if the medium that comes next is more dense or it won't be inverted if the medium is less dense.

19. What is meant by Collision of waves? When two waves traveling in opposite directions through the same medium collide, the amplitude of the resulting wave will be the sum of the two initial waves. This is called interference and there are of two types:

20. What is meant by a constructive interference? Constructive interference is when the amplitudes of the initial waves are in the same direction. The resulting wave will be larger than the original waves. The highest point of a constructive interference is called an antinode.

21. What is meant by Destructive interference? Destructive interference is when the amplitudes of the initial waves are opposite. The amplitude of the resulting wave will be zero. The point in the middle of a destructive interference is called a node and it never moves.

22. What is meant by reflection of waves? When a wave hits a barrier, it will be reflected depending on the direction of the barrier (normal). The angle between the incident wave and the normal is the same as the angle between the normal and the reflected wave.

23. What is meant by refraction? When a wave enters a different medium (more shallow region) at an angle, the direction of waves changes. This change is called refraction.

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24. What is meant by diffraction? When a wave travels through a small hole in a barrier, it bends around the edges. This is called diffraction.

25. What happen to the following wave properties if it undergoes reflection, refraction and

diffraction?

Wave parameter Reflection Refraction Diffraction

speed same changes same

frequency same same same

wavelength same changes same

Amplitude changes changes same

Phase changes changes same

Direction changes changes changes

Skills 1. The velocity of a wave is 420 m/s. If the frequency of the wave is 85 Hz, what is its

wavelength?

2. If a wave with a wavelength of 5.0 m has a 3.0 * 10-3 s period (a) what is its frequency? (b) what is its velocity?

3. What is the period of a sound wave that has a frequency of 163 Hz?

4. If a wave with a frequency of 342 Hz and a velocity of 234 m/s is produced.. (a) what is its wavelength? (b) how far is the wave after 3.6 s?

5. A traveling wave is produced on a rope. The wave travels until it hits a wall and it is reflected. If the speed of the wave is 1.8 m/s and it takes 10.4 s to reach the origin again, .(a) how long is this rope? (b) what is the wavelength of the wave if it has a period of 2.1 s?

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Light

(a) Reflection of Light

3 Properties of Waves Where to go! 3.2 Light E5.1, E166

A Reflection of Light E5.2, E169

Core-1 Describe the formation, and give the characteristics, of an optical image by a plane mirror E170-E171

Core-2 Use the law of angle of incidence-angle of reflection E169 Sup-1 Perform simple constructions, measurements and calculations E171, lab manual


1. Explain what is meant by Reflection of light 2. Explain what is meant by normal 3. Explain what is meant by the incident angle 4. Explain what is meant by the reflection angle 5. State the reflection law of light 6. List the characteristics of an image in a plane mirror 7. Explain how to draw the image of an object in a plane mirror

1. What is meant by Reflection of light? When a ray of light hits the surface of an object, part of the light is absorbed and part is reflected.

2. What is meant by normal? If we draw a line perpendicular to a surface, this line is the normal of the surface.

3. What is meant by the incident angle? Is the angle between the normal and the incident ray.

4. What is meant by the reflection angle? Is the angle between the normal and the reflected ray.

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5. State the reflection law of light? 1- The incident ray of light, normal, and reflected ray are in the same plane 2- The reflection angle is equal to the incident angle

6. What are the characteristics of an image in a plane mirror? 1. The image has the same size as the object 2. The image distance from mirror is the same as the object distance from mirror 3. The image distance from the object is twice the distance from the mirror to the object 4. The image is virtual and upright 5. The image is laterally inverted

7. Explain how to draw the image of an object in a plane mirror?

1. Draw a line from the most top point in the object that is perpendicular to mirror 2. Draw a line from the most top point in the object that is makes an angle with the

Normal to mirror 3. Draw a line from the lowest point in the object that is perpendicular to mirror 4. Draw a line from lowest point in the object that is makes an angle with the Normal to

mirror

8. 9.

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(b) Refraction of Light

3 Properties of Waves Where to go! 3.2 Light E166

B Refraction of Light E5.4, E177 Core-1 Describe an experimental demonstration of the refraction of light E179

Core-2 Use the terminology for the angle of incidence "i" and angle of refraction "r" and describe the passage of light through parallel-sided transparent material

E177

Core-3 give the meaning of the critical angle E179 Core-4 Describe internal and total internal reflection E179 Sup-1 Use the definition of refractive index "n" in terms of speed E178 Sup-2 recall and use the equation n=sin(i)/sin(r) E177 Sup-3 Describe the action of optical fibers E180


1. Explain what meant by refraction of light 2. Explain what is meant by "highly dense medium" 3. Explain what is meant by "less dense medium" 4. Explain wow lights bends when light moves from medium to another 5. Show when a ray of light enters a denser medium, it is bent towards the normal. 6. Show when a ray of light enters a less dense medium, it is bent away from the normal. 7. Explain what is meant by index of refraction 8. Define the followings: incident angle, refraction angle, incident ray, reflected light,

Normal 9. Explain what is meant by critical angle 10. Explain what is meant by internal reflection and total internal reflection of light 11. List two applications in ourlives which uses the concept of critical angle and the total

internal reflection.

Refraction of light

1. What is meant by refraction of light? When a ray of light passes from one medium to another, it bends. This bending of light is called "refraction".

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2. What is meant by "highly dense medium"? If light travels slower in a medium than another medium, then this medium is described as " highly dense medium" than the other.

3. What is meant by "less dense medium"? If light travels faster in a medium than another medium, then this medium is called less denser than the other

4. How lights bends when light moves from medium to another? When a ray of light enters a denser medium, it is bent towards the normal. When a ray of light enters a less dense medium, it is bent away from the normal.

5. Show when a ray of light enters a denser medium, it is bent towards the normal.

6. Show when a ray of light enters a less dense medium, it is bent away from the normal.

7. What is meant by index of refraction? There is an index of refraction (n) is defined as the speed of light in vacuum divided by the speed of light in medium.

8. Define the followings: incident angle, refraction angle, incident ray, reflected light, Normal? incident angle the angle between normal and incident ray refraction angle the angle between normal and refracted ray

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incident ray the light ray that is coming from light source and strikes the boundary surface. reflected light the light ray that emerges from the second medium Normal the perpendicular line on the boundary surface.

9. What is meant by critical angle? The critical angle is the angle of incidence for which the refracted ray is at 90 degrees with the normal.

10. What is meant by internal reflection and total internal reflection of light? Internal reflection occurs when the incident angle is equal to or less than the critical angle where some of the light ray will be internally reflected and some refracted.

The green region shows the the refracted light area . The cyan region represented the reflected light are.

Total internal reflection occurs when the incident angle is always greater than the critical angle where all light ray will be internally reflected.

11. List two applications in ourlives which uses the concept of critical angle and the total internal reflection. 1- Cameras: Cameras uses prisms to reflect light instead of mirror.

2- Fiber optics: Fiber optic are thin, flexible glass rods used to carry light. The light enters

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the fiber optics at angle greater than the critical angle of the fiber. In side the fiber light is totally reflected from one side to the other until it leaves the fiber from the other end.

12.

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(c ) Thin Converging Lenses

3 Properties of Waves Where to go!

3.2 Light E166

C Thin Converging Lenses E5.5, E181 Core-1 Describe the action of a thin converging lens on a beam of light E181 Core-2 Use the term focal length E181

Core-3 Draw ray diagram to illustrate the formation of a real image by a single lens E181-182

Sup-1 Draw ray diagram to illustrate the formation of a virtual image by a single lens E181-184

Sup-2 Use and describe the use of a single lens as a magnifying glass. E186


1. List the main two types of lenses 2. Explain what is meant by the principle focus of a convex lens 3. Explain what is meant by the principal focus of a concave lens 4. Explain what is meant by the principal axis lens 5. Explain how to find the focal length of convex lens rapidly 6. Explain how to find the focal length of convex lens accurately 7. Explain how to distinguish by structure between a convex lens and concave lens 8. Explain the relation between the focal length and the curvature of a lens 9. Explain why in practice a convex lens may not bring parallel rays to an exact point

focus. 10. Explain how to draw the image of an object placed in front of a convex lens 11. Explain how to draw the image of an object placed in front of a concave lens 12. State the properties of the image of an object if placed in front of a convex at

(a) u<F (b) u>2F (c) 2F>u>F (d) u=2F (e) u=F 13. State the minimum possible distance between an object and its image under a convex

lens. 14. Uses the lenses formula and the magnification factor. 15. Define "real image" and "virtual image"

1. What are the main two types of lenses? Convex and Concave lenses

2. What is meant by the principle focus of a convex lens? The principle focus of a convex lens is the point at the axis that passes through the optical center of the lens and where the incident rays parallel to the axis are refracted passing through it.

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3. What is meant by the principal focus of a concave lens? The principal focus of a concave lens is the point at the principle axis that passes through the optical center of the lens and where the incident rays parallel to the axis are refracted so that their extensions pass through it.

4. What is meant by the principal axis of a lens? Is a straight line that passes through the optical center and the focus of the lens

5. How could you find the focal length of convex lens rapidly?

6. How could you find the focal length of convex lens accurately?

7. How could you distinguish by structure between a convex lens and concave lens? Convex lenses are thick in the middle while concave lens are thin in the middle

8. What is the relation between the focal length and the curvature of a lens? inverse relation

9. Give two reasons why in practice a convex lens may not bring parallel rays to an exact point focus.

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1- Convex lenses refract light of different colors by slightly different amount. So they will not converge in one point

2- Convex lens converge parallel ray in one point if and only if they are very close to the principle axis.

10. Explain how do we draw the image of an object placed in front of a convex lens? 1- Draw a straight ray from the top most point in the object that passes through the optical center.

2- Draw a straight ray from the most top point in the object parallel to the principle axis and then refract it so it passes in the focus

3- Draw a straight ray passing in the focus and refract it parallel to the principle axis

11. Explain how do we draw the image of an object placed in front of a concave lens? >

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12. An object is placed beyond the focal length of a convex lens. Draw a ray diagram to show how the image is formed and describe the image nature?

13. An object is moved from beyond the focal length of a convex lens toward its optical center, what effect will occur on the image size, and position?

14. State where an object should be placed if the image formed by a convex lens is to be: a- large, upright, and virtual. u<F b- real and smaller than the object. u>2F c- real and larger than the object. 2F>u>F d- real and the same size as the object. u=2F e- real and at the minimum possible distance from the object. u=F

15. What is the minimum possible distance between an object and its image under a convex lens? It is 4 times the focal length.

16. Describe the lenses formula and the magnification factor.

u: distance between object and optical center v: distance between image and optical center + (positive) real image, inverted - (negative) virtual image and upright f: focal length. + (positive) for convex lenses - (negative) for concave lenses L': image length L: object length m: magnification

17. Define "real image" and "virtual image"? Real image is an image that can be put on screen Virtual image is an image that cannot be put on screen.

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Problems 1. A 3cm high object is placed 24 cm away from a convex lens of focal length 8 cm.

Calculate the position, height and nature of of the image. given: L=3cm, u=24 cm, f=+8 cm required: v?, L'?, image properties? Solution: 1/u+1.v=1/f , 1/24+1/v=1/8, 1/v=1/8-1/24=2/24=1/12, v=12 cm m=L'/L=v/u, L'/3=12/24, L'=1.5 cm image: real, inverted, smaller

2. A 3cm high object is placed 3 cm away from a convex lens of focal length 8 cm. Calculate the position, height and nature of of the image. given given: L=3cm, u=3 cm, f=+8 cm required: v?, L'?, image properties? Solution: 1/u+1.v=1/f , 1/3+1/v=1/8, 1/v=1/8-1/3=-5/24=1/12, v= -24/5= - 4.8 cm m=L'/L=v/u, L'/3=4.8/3, L'=4.8 cm image: virtual, upright , larger

3.

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(d) Dispersion of Light


3.2 Light E166

D Dispersion of Light E5.8, E191

Core-1 Give a qualitative account of the dispersion of light as illustrated by the action of a prism E191


1. List the primary colors 2. Explain why red, green and blue are called primary colors 3. Explain how do we obtain secondary colors 4. List the secondary colors 5. List the colors of light 6. Explain what is meant by a monochromatic “single component” of light 7. Explain what is meant by a polychromatic “compound component” of light 8. Explain the white light is not a monochromatic light 9. Explain what is meant by dispersion of light 10. Explain how to isolate the color components of white light 11. Explain that white color components form visible spectrum 12. List the color components of light spectrum in order. 13. Explain what is meant by a continuous spectrum 14. Explain why while reading a book, by some eyeglasses we view some colors at the edges

of text

1. What are the primary colors? Red, green and blue are known as primary colors.

2. Why red, green and blue are called primary colors? Because when they are added together white light is formed.

3. How do we obtain secondary colors? By mixing primary colors in pairs we obtain secondary colors.

4. What are the secondary colors? Red and green produce yellow. Blue and red produce magenta blue and green produce cyan.

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5. What are the colors of light? Red, orange, yellow, green, blue, indigo, violet

6. What is meant by a monochromatic light (single component)? A single wave with single frequency and wavelength.

7. What is meant by a polychromatic light (compound component)? A light which is constructed from single light components

8. Is white light a monochromatic or polychromatic? It is a polychromatic light.

9. What is meant by dispersion of light? It means the separation of the light components.

10. How do we isolate the color components of white light? Using prism

11. The white color components are called the visible spectrum. Why? Because all the color can be seen by the human eye.

12. List the color components of light spectrum in order. Red, orange, yellow, green, blue, indigo, violet

13. What is meant by a continuous spectrum? When the spectrum colors are projected on a screen they have no separation distance and thus they are continuous.

14. While reading a book, by some eyeglasses we view some colors at the edges of text. Why? Because white light is dispersed by the eyeglass into the eye into its color components.

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(e) Electromagnetic Spectrum


3.2 Light E166

E Electromagnetic Spectrum E5.11, E204

Core-1 Describe the main features of the electromagnetic spectrum and state that all e.m. waves travel with the same high speed in vacuo. E204, E205

Sup-1 State the approximate values of the speed of electromagnetic waves. E204

Sup-2 use the term monochromatic See Word of Physics


1. List the bands of an electromagnetic spectrum 2. List some of the properties of electromagnetic waves 3. List some applications to the bands of the electromagnetic spectrum 4. List how the bands of the electromagnetic spectrum are detected 5. List some sources for the bands of the electromagnetic spectrum

1. What are the bands of an electromagnetic spectrum? Radio waves, Microwaves, Infrared waves, Visible light, Ultra violet, X-ray, Gamma ray. Of all the electromagnetic waves, light is the only portion of waves that can be detected by the human eye.

2. List some of the properties of electromagnetic waves. 1. Travel in straight lines 2. Have a constant speed of 300,000,000 m/s. 3. They are transverse waves 4. They propagate in vacuum.

3. List some applications in ourlives to the following bands of the electromagnetic

spectrum 1. Radio waves: wireless-communication 2. Microwaves: Radar, Telemetry, Electron spin resonance 3. Infrared waves: remote control, heat, night-sight 4. Visible light: Stimulate the retina, Affects Photoelectric film, Initiate Photo-

synthesis

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5. Ultra violet: ionization, florescence, chemical reactions, Produce Photoelectric effect, Fluorescent tubes, Photographic film

6. X-ray: destroy cancer cells, locate bone fractures, internal imperfections of welded joints, structure of complex molecules.

7. Gamma ray:

4. List how bands of the electromagnetic spectrum are detected. 1. Radio waves: radio receivers 2. Microwaves: crystal detectors 3. Infrared waves: Thermopile, Special photographic film 4. Visible light: eye, Photoelectric cell, photographic film 5. Ultra violet: Photoelectric cell, Fluorescent tubes, Photographic film 6. X-ray: Geiger-Muller tube, Ionization chamber, solid state detectors, photographic

film, Scintillation counters 7. Gamma ray: Geiger-Muller tube, Ionization chamber, solid state detectors,

photographic film, Scintillation counters

5. List applications for the following bands of the electromagnetic spectrum 1. Radio waves: communications 2. Microwaves: heating and communication 3. Infrared waves: remote control, medicine 4. Visible light: vision, photography, 5. Ultra violet: night vision, 6. X-ray: industry, 7. Gamma ray: nuclear industry

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Sound 3 Properties of Waves Where to go!

3.3 Sound E5.13, E210

Core-1 Describe the production of sound by vibrating sources E210 Core-2 Describe the longitudinal nature of sound waves E210 Core-3 State the approximate range of audible frequencies

Core-4 Show an understanding that a medium is required to in order to transmit sound waves E211

Core-5 Describe an experiment to determine the speed of sound in air E212

Core-6 Relate the loudness and pitch of sound waves to amplitude and frequency E214

Core-7 Describe how the reflection of sound may produce an echo E212 Sup-1 Describe compression and rarefaction E210

Sup-2 State the order of magnitude of the speed of sound in air, liquids, and solids E211


1. Describe how sound is produced 2. Describe the longitudinal nature of sound 3. State the approximate range of audible sound 4. Explain what is meant by infrasonic 5. Explain what is meant by ultrasonic 6. Describe an experiment to show that sound requires a medium to be transmitted 7. Describe an experiment to determine the speed of sound 8. Explain what is meant by the followings terms intensity, loudness, pitch 9. Explain the relations between loudness, pitch, frequency, temperature, intensity 10. List the factors which sound intensity depends on 11. Describe how the reflection of sound may produce echo 12. Describe compression and rarefaction 13. Compare between sound speed in liquids, gases, and solids

1. Describe how sound is produced? Sound is produced by vibrating an object into its surrounding medium. The vibration produces compressions and rarefactions in the surrounding medium resulting in longitudinal waves. When compressions and rarefactions reach the ear drum, they result in the sensation of sound provided that the frequency of the waves is between 20-20000Hz.

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2. Describe the longitudinal nature of sound? Sound produces longitudinal waves which cause vibrations in the medium in the direction of the traveling wave.

3. What is the approximate range of audible sound? Audible sound has a frequency between 20-20000HZ

4. What is meant by infrasonic? Sound waves with frequency below 20Hz are called infrasonic sound waves

5. What is meant by ultrasonic? Sound waves with frequency above 20000Hz are called ultrasonic sound waves

6. Describe an experiment to show that sound requires a medium to be transmitted?

Equipment: 1-electric bell, 2- glass jar, 3- vacuum pump, 4-power source

By removing the air from the jar, it is possible to show that sound cannot travel through vacuum.

7. Describe an experiment to determine the speed of sound.

We take a sound source and produce a pulse of sound from the source as shows by the red spot. During that the timer receives a starting signal to start counting time The sound wave will ravel and strikes the wall. It will be reflected off the wall and then be detected by the sound receiver, which will send a stop signal to the timer.

The sound traveled the double the distance and therefore its speed is given by speed=2*distance/time taken.

8. What is meant by the followings terms? Intensity: is the power carried by the wave through a unit of area erected perpendicular to the direction of propagation. Loudness: is a term used to measure the human perception of sound Pitch: is the timbre, quality of sound, tone, or sharpness.

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9. What is the relation between frequency, amplitude, pressure, temperature and loudness, pitch, intensity, speed.

Parameter Frequency Amplitude Pressure Temperature

loudness independent directly independent independent

pitch directly independent independent independent

intensity directly2 directly2 independent directly

speed independent independent independent directly

10. What are the factors which the intensity of sound depends on? frequency square, speed, amplitude square, medium density. Where I=2vρπ2f2A2 where is ρ: density (kg/m3) f: frequency (Hz) A: Amplitude (m) v: speed (m/s)

11. Describe how the reflection of sound may produce echo? Sound echoes are sound waves reflected off large objects. They are heard after a short time of the original sound because the reflected wave needs time to bounce off objects and reach the observer.

12. Describe compression and rarefaction?

When the speaker cone is pushed toward the ear, it compresses the air as shown. When the speaker cone is pulled a way from the ear, it stretches the air resulting in rarefaction. The series of compressions and rarefactions are traveling through air until it reaches the ear drum.

13. Compare between sound speed in liquids, gases, and solids? 330m/s in air, 1400 m/s in water, and 5000 m/s in solids.

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Electricity and Magnetism Introductory Electronics

(a) Cathode Rays

4 Electricity and Magnetism Where to go!

4.6 Introductory Electronics E230

A Cathode Rays E8.1, E324 Core-1 Describe the production and detection of cathode ray E324

Core-2 Describe the cathode ray deflection in electric fields and magnetic fields E325

Core-3 Deduce that the particles emitted in thermionic emission are negatively charges E326

Core-4 State that the particles emitted in thermionic emission are electrons E324

Sup-1 Distinguish between the direction of flow of electron current and conventional current E326 (see Fig7b)


1. Explain what meant by a cathode ray 2. Explain why it is called cathode ray 3. Explain what is meant by thermionic emission 4. Explain the structure of a cathode ray tube 5. Explain why the air is removed from the glass tube 6. Explain how do we generate cathode ray 7. Explain why current does not flow in the circuit shown 8. List the basic properties of cathode ray 9. Explain an experiment to show that cathode ray travels in straight lines 10. Explain an experiment to show that cathode ray can be deflected by electric field 11. Explain an experiment to show that cathode ray can be deflected by magnetic field 12. Explain an experiment to show that cathode ray is made of negatively charged particles 13. Show the difference between the direction of flow of electron current and conventional

current for the cathode ray?

1. What meant by a cathode ray? A cathode ray is a beam of fast-moving electrons.

2. Why it is called cathode ray? Because it emerges from the cathode

3. What is meant by thermionic emission? It is the break up of electrons off metals into the space surrounding them due to the gained energy from heat.

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4. Explain the structure of a cathode ray tube? The tube is made of glass with all air removed from it. Inside the glass there are two pieces of metal called electrodes. One of these is called the anode and the other is called the cathode.

5. Why the air is removed from the glass tube? It is removed so that the electrons are free to move without colliding with air molecules

6. Explain how do we generate cathode ray? We connect the filament of the cathode to a suitable power supply and we connect the anode to the positive terminal of a high voltage power supply as shown below. When the filament heats the cathode, the electrons start to gain energy and escape from the cathode surface. Electrons leaving the cathode are accelerated toward the anode due to the high potential and the positive charge on the anode. The accelerated electrons form a fast-moving beam of electrons called "cathode ray".

7. Explain why current does not flow in the circuit shown? In the circuit below, the anode has a negative charge and thus it will not attract the escaped electrons. As a result no current will be detected by the ammeter shown in the circuit.

8. List the basic properties of cathode ray? 1. Travel in straight lines 2. A beam of negatively charged particles 3. Can be deflected by electric field 4. Can be deflected by magnetic field

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5. Produce fluorescence (glow) when they hit some materials. This property is used to design screens for TVs, computers, oscilloscopes, ..etc.

9. Explain an experiment to show that cathode ray travels in straight lines? As shown in figure below, we put an object like the Maltese cross. When the cathode ray accelerates toward the screen part of it will be blocked by the cross and the other part is reach the screen. On the screen, we see an image exactly proportional to the cross, which indicate that electrons must have traveled in straight lines.

10. Explain an experiment to show that cathode ray can be deflected by electric field? The circuit below shows that when the cathode ray enters the electric filed set by the two plates it is deflected toward the positive terminal. This happens because the positive charge on the top plate as shown attracts the electrons.

11. Explain an experiment to show that cathode ray can be deflected by magnetic field?

12. Explain an experiment to show that cathode ray is made of negatively charged

particles?

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13. Show the difference between the direction of flow of electron current and conventional current for the cathode ray?

14.

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(b) Simple Treatment of cathode ray oscilloscope

4 Electricity and Magnetism Where to go!

4.6 Introductory Electronics E8.3, E332

B Simple Treatment of cathode ray oscilloscope E8.2, E 328

Core-1 Describe in outline the basic structure and action of a cathode-ray oscilloscope E328

Core-2 Use and describe the use of a cathode-ray oscilloscope to display waveforms E329

Sup-1 Use and describe the use of a cathode-ray oscilloscope to measure p.d's and short intervals of time. E330


1. Describe the structure of a cathode-ray oscilloscope 2. Explain the function of filament 3. Explain the function of grid 4. Explain the function of anode 5. Explain the function of the electron-gun 6. Explain the function of X-plates 7. Explain the function of Y-plates 8. Explain the function of fluorescent screen 9. Explain the function of time-base 10. Explain what can be measured by an oscilloscope 11. Explain how to use an oscilloscope to measure the voltage of an AC signal and its

period.

1. Describe the structure of a cathode-ray oscilloscope

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2. What is the function of filament? The filament, a tiny tungsten which is heated by current, gives off electrons due to heat generated by an electric current.

3. What is the function of grid? The grid controls the brightness. When the grid is made negative it pushes back some electrons so that fewer of them reach the screen.

4. What is the function of anode? The anode accelerate electrons toward the screen.

5. What is the function of the electron-gun? The electron gun makes a narrow beam of electrons. Its cathode gives off electrons and the anode accelerate them.

6. What is the function of X-plates? The X-plates are uses to move the electrons beam across the x-axis of the screen.

7. What is the function of Y-plates? The Y-pates are used to move the electrons beam up and down the screen along the y-axis of the screen. When an AC signal is placed at the Y-plates, they move the beam up and down resulting in a moving spot on the screen. So, by these plates we can dray the variations of an electrical signal with respect to time.

8. What is the function of fluorescent screen? The screen is coated in a fluorescent material. It shows a bright spot where the electron beams strikes it. The screen also is divide into 1 cm squares. Each square is called a division. The horizontal divisions represents units of time set by the time base and the vertical divisions represents the gain in units of volts set by the gain-control of the

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oscilloscope.

9. What is the function of time-base? The time base changes the voltage across the x-plates so that the beam moves from left to right across the screen. When the beam is at the right side of the screen, the time-base circuits turn off the beam and starts at left side. This process is repeated many times in a second. The number of repetition is called the frequency of the time base.

10. What can be measured by an oscilloscope? An oscilloscope can be used to measure the (1) the peak voltage of an AC signal and (2) the period of the AC signal.

11. Explain how to use an oscilloscope to measure the voltage of an AC signal and its period.

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(c) Action and Use of Circuit Components

4 Electricity and Magnetism Where to go! 4.6 Introductory Electronics E8.3, E332

C Action and use of circuit components E332 Core-1 Describe the action of a variable potential divider (potentiometer) E332

Core-2 Describe the action of thermistors and light dependent resistors and show understanding of their use as input transducers E252, E333

Core-3 Describe the action of a capacitor as an energy store and show understanding of its use in time delay circuits E333, E336

Core-4 Describe the action of a reed switch and a reed relay. See Word of Physics Core-5 Show understanding of the use of reed relays in switching circuits See Word of Physics

Core-6 Recognize and show understanding of circuits operating as light-sensitive switches and temperature operated alarms (using a reed relay or other circuits)

See Word of Physics

Thermistors Objectives: The student should be able to …

1. Explain what is a thermistor 2. Explain the relation between the resistance of a thermistor and temperature 3. Explain the main applications of a thermistor 4. List applications that uses thermistors 5. Draw a resistance-temperature graph for a thermistor 6. Draw a circuit that represents a heat-operated switch using a thermistor 7. Design a circuit that will operate at cold-temperatures 8. Design a circuit that will operate at hot-temperature 9. Explain the operation of the circuit shown below 10. Explain the operation of the circuit shown below

1. What is a thermistor? A thermistor is a thermal-dependent resistor. It is derived from thermal-resistor.

2. What is relation between the resistance of a thermistor and temperature? The relation is an inverse relation. When the temperature is increased, the thermistor resistance decreases and when then temperature is decreased the resistance is increased.

3. What is the main application of a thermistor? A thermistor is used in the design of control-circuits which require automatic switching that depends on temperature.

4. List applications that uses thermistors 1. Fire alarm 2. Air conditions 3. Refrigerators

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5. Draw a resistance-temperature graph for a thermistor?

6. Draw a circuit that represents a heat-operated switch using a thermistor?

7. Design a circuit that will operate at cold-temperatures. A thermistor usually has a resistance in the order of 1M ohm at a cold state and has a typical resistance in the order of 100 ohms at hot state.

At cold temperature, the above circuit will supply a voltage of V2=Vin R2/(R1+R2)=12*1M/(5000+1M)= 0.995 12=11.94 volts which is above 6 volts and will energize the relay and thus the system. At hot temperature, the circuit will supply a voltage of V2=Vin R2/(R1+R2)=12*100/(5000+100)= 0.02 12=0.24 volts which less than 6 volts and is not enough to energize the relay. Thus, the system is ON in cold temperatures and OFF in hot temperatures.

8. Design a circuit that will operate at hot-temperature. A thermistor usually has a resistance in the order of 1M ohm at a cold state and has a typical resistance in the order of 100 ohms at hot state.

At cold temperature, the above circuit will supply a voltage of V2=Vin R2/(R1+R2)=12*300/(300+1M)= 0.03% 12=0.0036 volts which is below 6 volts and will not energize the relay and thus the system. At hot temperature,, the circuit will supply a voltage of V2=V2=Vin R2/(R1+R2)=12*300/(300+100)= 75% 12=9 volts which above 6volts and is enough to energize the relay and thus the system. Thus, the system is OFF in

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cold temperatures and ON in hot temperatures.

9. Explain the operation of the circuit shown below?

At cold temperature, the above circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*300/(300+1M)= 0.03% 12=0.0036 volts which is below 6 volts and will not energize the relay and thus the system. At hot temperature,, the circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*300/(300+100)= 75% 12=9 volts which above 6volts and is enough to energize the relay and thus the system. Thus, the system is OFF in cold temperatures and ON in hot temperatures.


At cold temperature, the above circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*1M/(5000+1M)= 0.995 12=11.94 volts which is above 6 volts and will energize the relay and thus the system. At hot temperature, the circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*100/(100+5000)= 0.02 12=0.24 volts which less than 6 volts and is not enough to energize the relay. Thus, the system is ON in cold temperatures and OFF in hot temperatures.

11.

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Light-Dependent Resistor (LDR) Objectives: The student should be able to …

1. Explain what is a LDR 2. Explain the relation between the resistance of an LDR and light intensity 3. Explain the main application of an LDR 4. List applications that uses LDR 5. Draw a resistance-light intensity graph for an LDR 6. Design a circuit that will operate at dark-time 7. Design a circuit that will operate at daytime 8. Explain the operation of the circuit shown below 9. Explain the operation of the circuit shown below

1. What is a LDR? LDR is a light dependent-resistor.

2. What is relation between the resistance of an LDR and light intensity? The relation is an inverse relation. When light-intensity is increased, the LDR resistance decreases and when then light-intensity is decreased the resistance is increased.

3. What is the main application of an LDR? An LDR is used in the design of control-circuits which require automatic switching that depends on light.

4. List applications that uses LDR. 1. Counting system 2. Control Street lights in cities 3. Elevators

5. Draw a resistance-light intensity graph for an LDR?

6. Design a circuit that will operate at dark-time. An LDR usually has a resistance in the order of 1M ohm at dark and has a typical resistance in the order of 100 ohms at light-time.

At dark time, the above circuit will supply a voltage of V2=Vin

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R2/(R1+R2)=12*1M/(5000+1M)= 0.995 12=11.94 volts which is above 6 volts and will energize the relay and thus the system. At daytime, the circuit will supply a voltage of V2=Vin R2/(R1+R2)=12*100/(5000+100)= 0.02 12=0.24 volts which less than 6 volts and is not enough to energize the relay. Thus, the system is ON in dark and OFF in daytime.

7. Design a circuit that will operate at daytime. An LDR usually has a resistance in the order of 1M ohm at dark and has a typical resistance in the order of 100 ohms at light-time.

At dark, the above circuit will supply a voltage of V2=Vin R2/(R1+R2)=12*300/(300+1M)= 0.03% 12=0.0036 volts which is below 6 volts and will not energize the relay and thus the system. At daytime, the circuit will supply a voltage of V2=V2=Vin R2/(R1+R2)=12*300/(300+100)= 75% 12=9 volts which above 6volts and is enough to energize the relay and thus the system. Thus, the system is OFF in dark time and ON in daytime.


At dark, the above circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*300/(300+1M)= 0.03% 12=0.0036 volts which is below 6 volts and will not energize the relay and thus the system. At daytime, the circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*300/(300+100)= 75% 12=9 volts which above 6volts and is enough to energize the relay and thus the system. Thus, the system is OFF in cold temperatures and ON in hot temperatures.


At dark, the above circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*1M/(5000+1M)= 0.995 12=11.94 volts which is above 6 volts and will energize the relay and thus the system. At daytime, the circuit will supply a voltage of V1=Vin R1/(R1+R2)=12*100/(100+5000)= 0.02 12=0.24 volts which less than 6 volts and is not enough to energize the relay. Thus, the system is ON in cold temperatures and OFF in hot temperatures.

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Reed Switches Objectives: The student should be able to …

1. Explain the various types of Reed switches 2. Describe the structure of normally open Reed switch 3. Describe the structure of normally close Reed switch 4. Describe the operation of a normally open switch 5. Describe the operation of a normally close switch 6. Describe the structure of Reed relay 7. Design a simple burglar alarm using Reed witches

1. What are the various types of Reed switches? 1- Normally-opened (NO) Reed switches 2- Normally-closed (NC) Reed switches

2. Describe the structure of normally open Reed switch? A normally open Reed switch consists of two magnetic strips (e.g. iron) sealed in a glass tube. The two strips are not in contact unless we apply a magnetic field that will work on attracting the two strips.

3. Describe the structure of normally close Reed switch? A normally close Reed switch consists of one magnetic strip (e.g. iron) and another none-magnetic strip sealed in a glass tube. The two strips are in contact unless we apply a magnetic field that will work on separating the normal contact between the two strips.

4. Describe the operation of a normally open switch? If a magnet is brought near a reed switch, it magnetizes each iron strip. The result is that the two strips are attracted to each other and they bend to touch each other

5. Describe the operation of a normally close switch? If a magnet is brought near a normally closed reed switch, it magnetizes iron strip. The result is that the strip is pulled a way from the none-magnetic strip causing the switch to be

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open.

6. Describe the structure of Reed relay? A Reed relay switch is a normal reed switch put inside a coil of wire so that it can be operated by current passing throughout the coil.

7. Design a simple burglar alarm using Reed witches?

A normally closed Reed switch can be used in burglar alarms. The reed switch is fixed in the door frame and a magnet in the door.

When the door closed the magnet keeps the NC reed switch open and no alarm will present. However, when some one opens the door, the magnet is displaced a way by the door. Thus the NC reed switch returns its normal state closing the electrical circuit which will activate the alarm system.

8.

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Potential Divider Objectives: The student should be able to …

1. Explain what is meant by a potential divider 2. Explain the structure of a potential divider that uses discrete resistors 3. Explain the operation of a potential divider that uses discrete resistors? 4. Explain the structure and the action of a potential divider that uses a rheostat

(Potentiometer) 5. Explain the function of the rheostat in the potentiometer 6. Explain the relation between the output voltage of a potential divider and the

apparatus connected to it

1. What does a potential divider mean? Potential divider is a circuit that allows us to use part of the voltage of a power supply with a fixed e.m.f.

2. Explain the structure of a potential divider that uses discrete resistors? A potential divider that uses discrete resistors uses two resistors in series connected to a fixed voltage power supply. The output of the divider is taken across one of the two resistors as shown in the diagram below.

3. Explain the operation of a potential divider that uses discrete resistors? The power supply generate a current that passes through the two resistors in series. This current, given by I=Vin/(R1+R2), passes through R1 and causes a voltage drop across R1 given by V1=IR1 and a voltage drop across R2 given by V2=IR2. The output voltage between "A" and "B" is given by Vout which is the same as V2.

4. Explain the structure and the action of a potential divider that uses a rheostat (Potentiometer)? A potential divider that uses a rheostat (variable resistor) is connected to a fixed voltage power supply over the full length of the resistor, Rt, and the output is connected to the sliding terminal of the rheostat. As the slider is moved to different positions, the voltage across length "L2" or resistor "R2", (between "A" and "C") is proportional to the resistance "R2" or length "L2".

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5. What is the function of the rheostat in the potentiometer? The rheostat acts as a voltage divider which enables one to choose the proper voltage. It used as a volume control in radios and other electronic circuits

6. What is the relation between the output voltage of a potential divider and the apparatus connected to it? The potential difference across the apparatus is directly proportional to the resistance across it.

7.

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Questions Bank Thermal Physics

These questions are listed to test yourself without the need to look at the answers

States of Matter

1. List the states of matter. 2. What is a solid? 3. What is a liquid? 4. What is a gas? 5. Why liquids are used to transfer forces in hydraulic machines? 6. List the properties of solids 7. List the properties of liquids 8. List the properties of gases

Molecular Modal

1. What are the basic assumptions of the KMTM? 2. List the properties of solids 3. List the properties of liquids 4. List the properties of gases 5. Why do solids have definite shape and volume? 6. Why do not liquids have fixed shape but have definite volume can flow? 7. Why do not gases have fixed shape, and definite volume but can flow? 8. Explain why gases are easily compressed? 9. Why liquids are used to transfer forces in hydraulic machines? 10. Explain why a spring returns to its original shape after removing the stretching force?. 11. Explain why a spring returns to its original shape after releasing compression from it? 12. Define temperature based on the molecular model? 13. What is the relation between temperature and kinetic energy of molecules? 14. What does it mean when an object is hotter than another object based on the molecular model? 15. Explain how gases produce pressure on the walls of their containers? 16. Explain how temperature increases the pressure of gases? 17. Explain how low temperature decreases the pressure of gases? 18. What does a Brownian motion mean? 19. Explain an experiment to demonstrate the Brownian motion.

Evaporation

1. Define evaporation? 2. At what temperature evaporation occurs? 3. What effect evaporation may leave on its liquid? 4. List examples that show the cooling effect of evaporation? 5. Explain how evaporation cools liquids? 6. List the factors which increase evaporation? 7. Why the increase in temperature increases evaporation? 8. Why the increase in liquid surface area increases evaporation? 9. Why winds and drought increase the rate of evaporation?

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Pressure Changes

1. What is the relation between gas pressure and volume at constant temperature? 2. State Boyle's law. 3. Explain the relation between pressure and volume using molecular theory? 4. Explain how gases produce pressure on the walls of their containers? 5. Explain how temperature increases the pressure of gases?

Expansion

1. Explain what is meant be expansion 2. Explain why things expand 3. Explain what happen when solids are heated 4. Explain what happen when solids are cooled 5. List the factors which affect the expansion of solids 6. Compare between the expansivity of solids, liquids, and gases. 7. List four real-life problems due to expansion of materials. 8. Explain what us meant by bimetal strip? 9. Describe the action of a bimetal? 10. Explain how to build a fire alarm using bimetals. 11. Explain what does a thermostat mean? 12. Explain the structure and the action of thermostat? 13. List some applications to thermostat in industry

Expansion of Liquids

1. Explain what happen when liquids are heated 2. Explain what happen when liquids are cooled 3. List the factors that affect the expansion of liquids 4. Compare between the expansivity of liquids and solids 5. Explain why when heating a liquid, its level initially decreases and then it increases to become

larger than the original level? 6. List some applications that use the expansion of liquids 7. Explain the effect temperature on volume of water 8. Explain when water has its minimum volume or higher density 9. Explain the effect temperature on density of water 10. Explain why filled bottles of water when placed in a freezer may burst when water is frozen 11. Explain why ice floats on water 12. Explain why the surface of a lake freezes while the deepest water stays at 4C

Expansion of Gases

1. Compare the expansion of gases to that of solids and liquids 2. Explain the effect of temperature on gas volume when pressure is constant 3. Explain the effect of temperature on gas pressure when volume is constant 4. Explain an experiment to show the effect of temperature on gas pressure 5. State the statement of "Charlie's law" 6. State the statement of the pressure law 7. State the statement of the Boyle's law 8. State the general law of gases?

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Temperatures

1. Define temperature? 2. What are the physical properties that are used to measure temperatures?

Thermometers

1. List the types of temperature meters? 2. List liquid-in-glass thermometers? 3. Describe the structure of liquid-in-glass thermometers? 4. Explain how liquid-in-glass thermometers operate? 5. List the basic properties of thermometers? 6. What is meant by the following terms: sensitivity, range, and uniformity? 7. How do we increase the sensitivity of a thermometer? 8. Explain how a decrease in tube diameter of a liquid-in-glass thermometer will increase

sensitivity? 9. Explain how an increase in volume of a liquid-in-glass thermometer will increase sensitivity? 10. How do we increase the range of a thermometer? 11. Explain how a decrease in volume bulb of a liquid-in-glass thermometer will increase range? 12. Explain how an increase in tube diameter of a liquid-in-glass thermometer will increase range?

Celsius Scale

1. List the three basic scales for temperature measurements? 2. What are the two fixed points in Celsius scale? 3. What is meant be "lower fixed point" and "upper fixed point"?

Kelvin Scale

1. Describe the Kelvin scale? 2. What is meant by "absolute-zero" temperature? What is the relation between Kelvin temperature

and Celsius temperature?

Mercury Thermometers

1. List four advantages of mercury as a liquid? 2. List three disadvantages of mercury?

Alcohol Thermometer

1. Describe alcohol thermometer. 2. List two advantages of Alcohol? 3. List three disadvantages of alcohol

Clinical Thermometers

1. Why a clinical thermometer has a narrow constriction just above its bulb 2. List the properties of a clinical-thermometer.

Thermocouple Thermometers

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1. Describe the structure of a thermocouple meter? 2. Describe the operation of a thermocouple meter? 3. List the advantages of a thermocouple thermometer?

Thermal Capacity

1. What is meant by thermal energy? 2. Explain what happen to the internal energy when the body is heated? 3. What is the relation between the rise in temperature and the amount of heat gained by an object? 4. What are the factors that affect the thermal energy? 5. What is meant by specific heat capacity? 6. Describe the specific heat of water? 7. Why creatures can to resist a high change in temperature? 8. What is meant by thermal capacity of a body? 9. Why water is used in central heating systems? 10. Explain the process of heat exchange? 11. State the law of conservation of energy?

Melting Point

1. What is meant by melting point? 2. What is meant by "latent heat of fusion"? 3. Why it is called "Latent heat"? 4. Explain why latent heat of fusion does not increase the object temperature by the molecular

theory? 5. What is meant by "Specific latent heat of fusion Lf"? 6. What is the amount of energy needed to change "m" kg from solid state to liquid state? 7. How much heat is needed to change 0.2 kg of ice into water? 8. What is the difference between boiling and evaporation? 9. Describe an experiment to measure the specific latent heat of ice. 10. Describe an experiment to measure the specific latent heat of steam.

Freezing

1. What is the difference between melting and freezing? 2. What are the types of substances that have defined freezing points? 3. How can we lower the melting point of ice?

Boiling Point

1. What is meant by boiling point? 2. What is meant by the "Latent heat of vaporization"? 3. Explain why the temperature remains constant until all the liquid changes to vapor? 4. What is meant by specific heat of vaporization? 5. What is the amount of heat absorbed during vaporization?

Conduction

1. Explain how heat is flows between two bodies?

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2. List three ways for transferring heat from on place to another? 3. What is meant by conduction? 4. How heat is transferred by conduction? 5. List some good conductors of heat. 6. List some poor conductors (insulators) of heat. 7. Explain an experiment to demonstrate the properties of good and bad conductors of heat

Convection

1. What is convection? 2. Describe convection in air. 3. Explain an experiment to show convection in air. 4. Explain an experiment to show convection in water. 5. Why warm fluid rises? 6. Explain convection of air by heat radiators. 7. Explain convection of air in refrigerators. 8. Explain convection of water in hot-water supply system. 9. Explain why the freezer compartment in a refrigerator is placed at the top. 10. Explain why a refrigerator does not work properly if the food is too tightly packed inside. 11. Explain why a radiator quickly warms all the air in a room, even though air is a very poor

conductor of heat. 12. Explain why warm water rises when surrounded by cooler water. 13. Explain how can we reduce heat lost due to convection?

Radiation

1. What is meant by heat radiation? 2. How heat reaches us from the Sun? 3. What is the relation between the heat in an object and and the wavelength of emitted EM? 4. What happens when heat radiations fall on an object? 5. How heat radiation can be detected? 6. What is meant by "bad emitters", "bad absorbers", "good emitters" and "good absorbers"? 7. Why people wear dark clothes in winter and white clothes in summer? 8. Why roofs of petrol tanks are painted in shiny aluminum? 9. Why vacuum flasks are made if double-walled glass vessels with vacuum between the walls and

the walls are silvered? 10. Why Greenhouses are made of glass walled rooms to keep warm climate in cold nights? 11. Why cloudy nights remain warm? 12. Explain an experiment to show that black surfaces are good absorbers of heat radiation and

shiny surfaces are good reflectors of heat radiations.

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General wave properties

General wave properties

1. What are the three types of waves? 2. What is meant by transverse waves? 3. What is meant by longitudinal waves? 4. What is meant by surface waves? 5. What is a pulse? 6. What is a wave? 7. What is meant by "wave period"? 8. What is meant by "wave frequency"? 9. What is meant by "wave amplitude"? 10. What is meant by "wave length"? 11. What is meant by "wave phase"? 12. What is meant by ray? 13. How the speed of a wave is related to its length and frequency? 14. Does the velocity of a wave depend on frequency or wavelength of the wave? 15. A radio wave has a frequency of 93.9 MHz (93.9 * 106 Hz). What is its period? 16. If the velocity of a radio wave is 300 000 000 m/s (light speed) and its wavelength is 3.0 m,

what is the frequency of the wave? 17. W hat happens to a wave when it moves form one medium to another medium? 18. What is meant by Collision of waves? 19. What is meant by a constructive interference? 20. What is meant by Destructive interference? 21. What is meant by reflection of waves? 22. What is meant by refraction? 23. What is meant by diffraction? 24. What happen to the following wave properties if it undergoes reflection, refraction and

diffraction?

Reflection of Light

1. What is meant by Reflection of light? 2. What is meant by normal? 3. What is meant by the incident angle? 4. What is meant by the reflection angle? 5. State the reflection law of light? 6. What are the characteristics of an image in a plane mirror? 7. Explain how to draw the image of an object in a plane mirror?

Refraction of Light

1. What is meant by refraction of light? 2. What is meant by "highly dense medium"? 3. What is meant by "less dense medium"? 4. How lights bends when light moves from medium to another? 5. Show when a ray of light enters a denser medium, it is bent towards the normal. 6. Show when a ray of light enters a less dense medium, it is bent away from the normal. 7. What is meant by index of refraction? 8. Define the followings: incident angle, refraction angle, incident ray, reflected light, Normal? 9. What is meant by critical angle? 10. What is meant by internal reflection and total internal reflection of light?

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11. List two applications in ourlives which uses the concept of critical angle and the total internal reflection

Thin Converging Lenses

1. What are the main two types of lenses? 2. What is meant by the principle focus of a convex lens? 3. What is meant by the principal focus of a concave lens? 4. What is meant by the principal axis of a lens? 5. How could you find the focal length of convex lens rapidly? 6. How could you find the focal length of convex lens accurately? 7. How could you distinguish by structure between a convex lens and concave lens? 8. What is the relation between the focal length and the curvature of a lens? 9. Give two reasons why in practice a convex lens may not bring parallel rays to an exact point

focus. 10. Explain how do we draw the image of an object placed in front of a convex lens? 11. Explain how do we draw the image of an object placed in front of a concave lens? 12. An object is placed beyond the focal length of a convex lens. Draw a ray diagram to show how

the image is formed and describe the image nature? 13. An object is moved from beyond the focal length of a convex lens toward its optical center,

what effect will occur on the image size, and position? 14. State where an object should be placed if the image formed by a convex lens is to be:

a- large, upright, and virtual. u<F b- real and smaller than the object. u>2F c- real and larger than the object. 2F>u>F d- real and the same size as the object. u=2F e- real and at the minimum possible distance from the object. u=F

15. What is the minimum possible distance between an object and its image under a convex lens. 16. Describe the lenses formula and the magnification factor. 17. Define "real image" and "virtual image"?

Dispersion of Light

1. What are the primary colors? 2. Why red, green and blue are called primary colors? 3. How do we obtain secondary colors? 4. What are the secondary colors? 5. What are the colors of light? 6. What is meant by a monochromatic light (single component)? 7. What is meant by a polychromatic light (compound component)? 8. Is white light a monochromatic or polychromatic? 9. What is meant by dispersion of light? 10. How do we isolate the color components of white light? 11. The white color components are called the visible spectrum. Why? 12. List the color components of light spectrum in order. 13. What is meant by a continuous spectrum? 14. While reading a book, by some eyeglasses we view some colors at the edges of text. Why?

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Electromagnetic Spectrum

1. What are the bands of an electromagnetic spectrum? 2. List some of the properties of electromagnetic waves. 3. List some applications in ourlives to the following bands of the electromagnetic spectrum 4. List how bands of the electromagnetic spectrum are detected. 5. List applications for the following bands of the electromagnetic spectrum

Sound

1. Describe how sound is produced? 2. Describe the longitudinal nature of sound? 3. What is the approximate range of audible sound? 4. What is meant by infrasonic? 5. What is meant by ultrasonic? 6. Describe an experiment to show that sound requires a medium to be transmitted? 7. Describe an experiment to determine the speed of sound. 8. What is meant by the followings terms? 9. What is the relation between frequency, amplitude, pressure, temperature and loudness, pitch,

intensity, speed. 10. What are the factors which the intensity of sound depends on? 11. Describe how the reflection of sound may produce echo? 12. Describe compression and rarefaction? Compare between sound speed in liquids, gases, and

solids?

Electricity and Magnetism

Cathode Rays

1. What meant by a cathode ray? 2. Why it is called cathode ray? 3. What is meant by thermionic emission? 4. Explain the structure of a cathode ray tube? 5. Why the air is removed from the glass tube? 6. Explain how do we generate cathode ray? 7. Explain why current does not flow in the circuit shown? 8. List the basic properties of cathode ray? 9. Explain an experiment to show that cathode ray travels in straight lines? 10. Explain an experiment to show that cathode ray can be deflected by electric field? 11. Explain an experiment to show that cathode ray can be deflected by magnetic field? 12. Explain an experiment to show that cathode ray is made of negatively charged particles? 13. Show the difference between the direction of flow of electron current and conventional current

for the cathode ray?

Simple Treatment of cathode ray oscilloscope

1. Describe the structure of a cathode-ray oscilloscope 2. What is the function of filament? 3. What is the function of grid?

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4. What is the function of anode? 5. What is the function of the electron-gun? 6. What is the function of X-plates? 7. What is the function of Y-plates? 8. What is the function of fluorescent screen? 9. What is the function of time-base? 10. What can be measured by an oscilloscope? Explain how to use an oscilloscope to measure the

voltage of an AC signal and its period.

Thermistors

1. What is a thermistor? 2. What is relation between the resistance of a thermistor and temperature? 3. What is the main application of a thermistor? 4. List applications that uses thermistors 5. Draw a resistance-temperature graph for a thermistor? 6. Draw a circuit that represents a heat-operated switch using a thermistor? 7. Design a circuit that will operate at cold-temperatures. 8. Design a circuit that will operate at hot-temperature.

Light-Dependent Resistor (LDR)

1. What is a LDR? 2. What is relation between the resistance of an LDR and light intensity? 3. What is the main application of an LDR? 4. List applications that use LDR. 5. Draw a resistance-light intensity graph for an LDR? 6. Design a circuit that will operate at dark-time. 7. Design a circuit that will operate at daytime. 8. Explain the operation of the circuit shown below? 9. Explain the operation of the circuit shown below?

Reed Switches

1. What are the various types of Reed switches? 2. Describe the structure of normally open Reed switch? 3. Describe the structure of normally close Reed switch? 4. Describe the operation of a normally open switch? 5. Describe the operation of a normally close switch? 6. Describe the structure of Reed relay? 7. Design a simple burglar alarm using Reed witches?

Potential Divider

1. What does a potential divider mean? 2. Explain the structure of a potential divider that uses discrete resistors? 3. Explain the operation of a potential divider that uses discrete resistors? 4. Explain the structure and the action of a potential divider that uses a rheostat (Potentiometer)? 5. What is the function of the rheostat in the potentiometer? 6. What is the relation between the output voltage of a potential divider and the apparatus

connected to it?

Documents

Basic IGCSE Second Year Class Notes On Physicsramadan.50megs.com/download/Microsoft Word - IGCSE...b) Light i) Reflection of light ii) Refraction of light iii) Lenses and thin converging