Abraham Darby Academy · energy consumed, you multiply the ... Task: complete the electricity crossword below using the clues at the bottom of the page. ADA ... conventional symbols

Abraham Darby Academy

KS3 Physics - Electricity

Study Booklet | Knowledge Series | 2017

ADA - KS3. Knowledge series | Physics | Electricity | Kevin Brace | 2017

Page 2 of 24

Key terms

Ammeter: a device used to measure electric current.

Ampere: Unit of current, e.g. the current in the bulb is 4 amps or amperes (A).

AC (mains) Power: = Energy Transfer/time: P = WD/t AC (mains) Current: = Power / Voltage: I = P/V AC (mains) Energy: Transferred = Potential Difference x Charge: E = V x Q Battery: a chemical supply of electrical energy. For example, common battery voltages

include 1.5V and 9V.

Cell: a store of internal energy that can be transferred as an electric current in a circuit. Electron: is a stable negatively charged component of an atom. Electrons exist

outside of and surrounding the atom nucleus. Each electron carries one unit of negative charge.

Electrical energy: The kind of energy carried by electricity. To find the amount of energy consumed, you multiply the rate of energy consumption (measured in watts) by the amount of time (measured in hours) that it is being consumed.

Volt (V): is a measure of the pressure applied to electrons to make them move. It is a measure of the strength of the current in a circuit and is measured in volts (V), the unit of electrical potential difference.

Hertz (Hz): The unit of frequency.

Electrical current (I): is defined as electrons flowing between two points having a difference in voltage. Current in a circuit is measured in (Amps).

A voltmeter: measures a potential difference across a circuit.

Electrical power: is measured in watts (W) or kilowatts (kW). 1W = 1 Joule per second. The power of an electrical appliance is the rate at which it transforms energy. Power = Work done (J) /time (s), Power = Current x Voltage.

AC/DC: alternating current (mains/household) or direct current (battery power)

Resistance (R): is a property that slows the flow of electrons. Resistance is measured

in ohms. The symbol used for ohms is Ω.

Joule: (J or kJ) - the unit of energy. May be presented as Kilojoules, 1kJ = 1000J

Potential difference: (voltage) between two points in an electric circuit is the work done (energy transferred) per coulomb of charge that passes between the points.

Ohms Law: states that the current that flows through a material is proportional to the voltage i.e. double the voltage, the current also doubles. The resistance of the material remains the same. Voltage = current x resistance.

In parallel: a parallel circuit, the current divides into two or more paths before recombining to complete the circuit. Lamps and other components in these different paths are said to be in parallel.

In series: connected to a circuit in such a way that the same current flows through each component in turn. Opposite of in parallel.

https://www.thoughtco.com/definition-of-atom-and-examples-604373

https://www.thoughtco.com/make-an-atom-model-603814


Page 3 of 24

Task: complete the electricity crossword below using the clues at the bottom of the page.


Page 4 of 24

Task: Label the three primary components of this hand torch. State whether the current is

AD or DC?

Task: Draw out the circuit of the above torch using SI electrical symbols.

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjIhfTi8d3UAhWEXhQKHYReA-EQjRwIBw&url=https://pixabay.com/en/photos/battery/?image_type%3Dvector&psig=AFQjCNHWb9JVV7SQD-YSdH8Kknn6VINt-w&ust=1498648170941627

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiziZT48d3UAhXHLhoKHbuJB78QjRwIBw&url=https://pixabay.com/en/photos/battery/?image_type%3Dvector&psig=AFQjCNGqMcLVVabk9oq36S-O2GaiQtzW_w&ust=1498648241771004



Page 5 of 24

Task: Explain how electrical energy is transformed to sound waves using a moving coil

loudspeaker. Use diagram below to illustrate your answer, and label parts C and D.

C:

D:


Page 6 of 24

Tasks: 1) Identify each component of this standard three pin domestic plug (including the

materials). State whether the material for each component is a conductor or an insulator.

2) At the bottom of the page, explain what is included in this plug to protect equipment,

and how the protection works. 3) Is this used in an AC or DC circuit?


Page 7 of 24

Task: Answer the following five questions, each with four possible answers. Underline the

correct answer(s).

1. Wires are usually coated in plastic because........

A) plastic can be easily coloured B) plastic helps the wires bend C) plastic helps the wires conduct electricity

D) plastic is an insulator

2. Two identical bulbs are in parallel in a complete circuit. A third identical bulb is

connected in parallel. What happens?

A) All the bulbs are dimmer B) All the bulbs are the same brightness C) The third bulb is brighter D) The third bulb is dimmer

3. Two identical bulbs are in parallel in a complete circuit. If one breaks........

A) the other bulb is brighter B) the other bulb is dimmer C) the other goes off D) the other stays on

4. If the size of a battery in a complete circuit increases........

A) the current decreases B) the current increases C) the current stays the same D) the voltage stays the same

5. The current in a series circuit containing two bulbs........

A) is larger between the bulbs B) is larger nearer the battery C) is smaller nearer the battery D) is the same at every place in the circuit


Page 8 of 24

Task: Data has been recorded from an experiment testing fuses. Construct a suitable line

graph using the tabulated data below. Choose a suitable scale for both axes. Add clear

labels.


Page 9 of 24

Task: Referring to the table and graph you have drawn for the previous task, what do

the fuse test results show?

Task: Referring to the table and graph you have drawn for the previous task, how does

the SWG number relate to the thickness of fuse wires?

Task: Referring to the table and graph you have drawnfor the previous task, what

thickness fuse would you suggest to use in an appliance designed to run on each of the

following A.C. currents?

A) 1A

B) 3A

C) 6A


Page 10 of 24

Task: What do all these different types of fuses have in common? Mark each image to

show the common part.

Task: Fill in the statements below using the words in bold underneath.

Ammeters, Earth, Safety, Melts, Electricity, Current, Circuit, Amps, Disconnect, Heat

____________measure how much electricity is passing through a _____________.

Current is measured in ____________.

Earth is connected from the metal appliance casing to the earth for___________.

Two core cables do not have an _______________wire.

Plastic does not conduct ____________________________.

An electrical fault can cause too great a________________.

A fuse or a circuit breaker in the live wire can __________________the circuit.

Too much current = ___________ = the fuse__________________.

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiI6rqz-d3UAhXLtxQKHcK1AqsQjRwIBw&url=https://commons.wikimedia.org/wiki/File:Industrial_NH1_Fuse_100A.jpg&psig=AFQjCNHw2AARhnsm0e34HLDkpk8YT7e3QA&ust=1498650225300225

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwimwpLX-N3UAhWDXhQKHYNZDNoQjRwIBw&url=https://commons.wikimedia.org/wiki/File:Fuse.jpg&psig=AFQjCNGiEQirNmMkV9atem7szWH2wSBjKw&ust=1498650053039122

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi2zeXg993UAhVGPhQKHfgCBEMQjRwIBw&url=https://commons.wikimedia.org/wiki/File:Electrical_fuse,_Bosch_type.png&psig=AFQjCNFasjPtu7i8nLL85GCfg9LvtVhh9Q&ust=1498649768994788

https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjZptX7993UAhWMcRQKHcLFBdUQjRwIBw&url=https://de.wikipedia.org/wiki/Datei:Electrical_fuses,_blade_type.svg&psig=AFQjCNGWykfk847pCTKOdHDgJDi-6WEekw&ust=1498649835507337


Page 11 of 24

Task: Complete the following statements by inserting the correct terminology into the

blank spaces.

Metals are good carriers of electricity. This property of metals is called ____________.

Most non-metals do not _________ electricity, and we call those _________________.

An electric current will only flow through a closed or ____________ circuit. A chemical

reaction inside of a battery pushes the current from the _________ terminal to the

___________ terminal.

There is a convention when referring to current flow, that says the electrons flow from the

_____________ to the _____________ terminal.

Task: Label the diagram below to show which terminal is positive and which is negative.

Use standard symbols ( - , +) to indicate the correct polarity. Which one of the two electron

flow directions is considered as convention, but appears illogical?


Page 12 of 24

Electrical circuits are drawn using standard symbols (SI) that represent common

components. You can see that the circuit diagram (schematic) on the right is both easier to

draw and universally understood. Use of standard symbols (SI) makes the diagram easier to

draw and read.

Task: label the component and the polarity of the two terminals on the symbol below using

conventional symbols.

Task: label the image below to show which battery terminal is positive and which is

negative, and write in the name of standard unit of measurement for battery strength.


Page 13 of 24

Task: Draw in a simple switched lamp circuit, powered by the above cell.

An electric current is a flow of charge. In wire, this will be a flow of electrons. Two things

are required for an electric current to flow:

1. something to transfer energy to the electrons, such as a battery or power pack, 2. a complete path for the electrons to flow through (a closed electric circuit).

Task: Label as many components that you can identify in the two circuits below.

http://www.bbc.co.uk/education/guides/zsfgr82/revision/1#glossary-zg8pcdm

http://www.bbc.co.uk/education/guides/zsfgr82/revision/1#glossary-z76d6sg


Page 14 of 24

Task: Identify these electronic components/items by their standard symbol (SI). Write a

short description of what each one does in the right hand column. SI symbol Name Description


Page 15 of 24

Task: Fill in the blanks for the statements below:

Current is measured in _________________ .

The symbol for ampere is _____________________.

A device called an ____________ is used to measure ______________flow around a

circuit. It must always be connected in _____________.

Potential difference is measured in _______________.

Potential difference is measured using a device called a _________________.

You must connect the voltmeter in _______________ to measure the potential

difference across a component in a circuit.

Tasks: 1) Modify the circuit below to ensure a free flow of electrons? 2) Draw in arrows to indicate the flow of electrons in your modified circuit. 3) State what happens to the bulb in your modified circuit. 4) Add in a symbol to indicate a cell is present.

CELL


Page 16 of 24

Task: In the middle column of the table write in the material that each item is it made from;

choosing the correct word in bold below. Indicate whether it is an electric insulator or a

conductor in the right hand column.

Wood, Cork, Steel, Concrete, Glass, Cotton, Bakelite, PTFE, Card, Rubber,

Leather, Plastic, Copper, Ceramic, Chipboard, Paper, Polystyrene.

Item Material Conductor or Insultor? Electric wires

Soles of shoes

Grips on cooking pans

Hair straighteners

Window

Pavement

Clothes

Football

Task: Label these two types of common circuits.


Page 17 of 24

Task: Help Elaine the electrician wire up a light. Answer the four questions below:

1. Draw a light circuit with a switch and a

power source. Use standard symbols

for each component. Label each

component in the circuit.

2. Ensure that you add in a component

into the circuit to protect the bulb in

case of a fault.

3. Add a note how would she test the

circuit to ensure it was operating with

the correct current?

4. Draw in a test apparatus to check the current flow through the bulb.


Page 18 of 24

Task: Answer the following seven revision questions. Underline the correct answer(s).

1. What does an electric circuit need to provide energy?

A bulb A cell A switch A wire

2. Which of the following does a light bulb do?

Change electrical energy into kinetic energy Change electrical energy into light energy

Change light energy into electrical energy Change light energy into thermal energy

3. In order to measure the voltage across a bulb in a circuit, the voltmeter is connected in

parallel with the battery parallel with the bulb series with the bulb

4. What is the unit of electric current?

Amp Ohm Volt Watt

5. If more bulbs are added in series in a series circuit, then .......

less current flows more current flows there is no change in current flow

6. What is used to measure the flow of current in a circuit?

Ammeter Battery Rheostat Voltmeter

7. In order to measure the current flowing through a bulb in a circuit, the ammeter is

connected in .......

parallel with the battery parallel with the bulb series with the bulb


Page 19 of 24

NOTE: Resistance is measured in ohms. The symbol used for ohms is Ω.

Task: In respect of resistance in a circuit; explain what these two equations (A and B) mean.

Draw a simple diagram to help explain each equation.

A. Req = R1 + R2 + .... Rn

B. Req = 1/{(1/R1)+(1/R2)+(1/R3)..+(1/Rn)}

Task: Using Ohm’s Law triangle (below) – write down each of the three main equations, and

explain what each of them is used for.


Page 20 of 24

Tasks: Studying the circuit below; 1) explain why the light bulb will not light up. 2) Draw a

correct switched circuit below using SI symbols.




Page 21 of 24

Task: Mains Electricity Calculations. Use the equations provided below to answer the

following eight questions.

Power = Energy Transfer/time

(W) (J) (s)

P = WD/t

Current = Power / Voltage

(A) (W) (V)

I = P/V

Energy Transferred = Potential

Difference x Charge

(J) (V) (C)

E = V x Q

1. An electric lamp transfers 500 J in 5 s. What is its power?

2. A device transfers 100 J in 5 s. What is its power?

3. How much energy is transferred by a 5 W lamp in 2 minutes?

4. Which is the greatest power rating? 300W, 0.3kW or 3000W

5. What is the power of a lamp with a current of 5A and potential difference of 1.5V?

6. A 0.5A lamp is connected to a 12 V battery. What is its power?

7. A television is rated at 460 W. What current flows through it at 230 V?

8. What current flows through a 1.15 kW electric fire at a potential difference of 230 V?

(Remember that 1.15 kW is 1,150 W)


Page 22 of 24

Task: Complete the electricity word search below.


Page 23 of 24

Task: Complete the chart below covering unsafe 3 pin plugs. Provide clear explanations.

PLUG Why is it unsafe? What needs to be done?


Page 24 of 24

NOTES

Image attribution

Most images are sourced from Wikimedia. These are shared under the Creative Commons Attribution-Share Alike 4.0

International license. Other images are sourced from online repositories, i.e. Pixabay. Those are released and shared under

CC0 Public Domain (i.e. freely reusable, and no attribution required).

Booklet released and shared under Attribution-NonCommercial-ShareAlike 2.0

Generic (CC BY-NC-SA 2.0)

https://creativecommons.org/licenses/by-nc-sa/2.0/

https://en.wikipedia.org/wiki/File:Adult_Digestive_System.png

https://en.wikipedia.org/wiki/en:Creative_Commons

https://creativecommons.org/licenses/by-sa/4.0/deed.en

https://creativecommons.org/licenses/by-sa/4.0/deed.en

https://pixabay.com/

https://creativecommons.org/publicdomain/zero/1.0/deed.en

https://creativecommons.org/licenses/by-nc-sa/2.0/

Documents

Abraham Darby Academy · energy consumed, you multiply the ... Task: complete the electricity crossword below using the clues at the bottom of the page. ADA ... conventional symbols