PHYSICS FINAL REVIEW – SPRING 2013

ENERGY / THERMAL PHYSICS

1. Describe the Kinetic Theory of Matter.The temperature of a substance measures the average kinetic energy of its particles.

2. How is the kinetic energy of a system related to its temperature? Its pressure? Its total internal energy?As kinetic energy increases, temperature, pressure, and internal energy increase proportionally as well. They are DIRECTLY PROPORTIONAL.

3. When energy converts from one form to another, is the conversion ever 100% efficient? What happens to some of the energy?In reality, no energy conversion is ever 100% efficient. Some energy is always converted to heat through friction.

4. What is specific heat? List two units for specific heat.Specific heat is the amount of energy needed to change the temperature of one gram of matter by one degree, either Celcius (C) or Kelvin (K). Units: J/goC or J/gK

5. How does specific heat relate to how fast a substance changes temperature?The higher a substance’s specific heat, the more energy it takes to change its temperature. Therefore, it will take longer to change temperature.

6. Describe the three types of heat transfer.RADIATION: heat transfer by electromagnetic waves. Does NOT require a medium.CONVECTION: heat transfer by movement of fluids (liquids or gases).CONDUCTIONL heat transfer by contact between two materials.

7. For each of the following, determine the mode of heat transfer.a. Feeling the heat from a fire on your hands RADIATIONb. Weather patterns in the atmosphere CONVECTIONc. Feeling the warmth from a cup of hot chocolate by holding the Starbucks cup

CONDUCTION8. Compare and contrast conductors and insulators. Give two examples of each.

CONDUCTORS allow heat & electricity to flow easily. EX: metal, saltwaterINSULATORS do not allow heat & electricity to flow easily. EX: wood, styrofoam

9. Good conductors “feel” cold on your skin. Good insulators do not. Why?The good conductor is quickly conducting the heat from your body away from you into the conductor and beyond, so you feel the heat lost. The good insulator does not allow that energy transfer, so you do not feel the heat loss since it is not happening

10. What is it about metals that make them good conductors of heat and electricity?Metals have loosely attached outer electrons that move easily, so they are able to transfer energy readily.

WAVES, SOUND & LIGHT

11. What do all waves transfer (carry)? What do they NOT transfer?Waves DO transfer energy. They DO NOT transfer matter.

12. Define the following wave properties and behaviors:

a. Wavelength: Distance between a point on a wave and the same point on the next wave

b. Amplitude: The mount of energy carried by a wave, its “height”c. Frequency: The number of waves that pass a given point in one secondd. Period: The amount of time it takes one wave to pass a given pointe. Reflection: The bouncing back of a wavef. Refraction: The bending of a wave due to crossing a boundary between two

mediag. Resonance: Occurs when an object absorbs energy at its natural frequency and

starts vibratingh. Total internal reflection: When a light wave enters a substance (such as a fiber

optic cable) and cannot escape because it cannot escape through the boundary of the cable’s edge

i. Interference: When two waves cross paths; can be constructive (additive) or destructive (subtractive)

j. Diffraction: The bending of a wave around a barrier or object

13. Label the following parts of a wave on the diagrams below: (1) wavelength, (2) amplitude, (3) crest, (4) compression, (5) trough, (6) rarefaction

14. Compare and contrast transverse and longitudinal waves. Give an example of each.Both transverse and longitudinal (compressional) waves carry energy. Transverse waves (EX: light) can travel without a medium. Longitudinal waves (EX: sound) must have a medium to travel.

15. What is required in order to create a wave?

(1)

(2)

(3)(4)

(5)(6)

To create a wave, a source of oscillations must be present. If there is not an oscillating source, a wave cannot be created.

16. How does the frequency of a source oscillation compare to the frequency of the wave it creates?A wave will have the same frequency as the source of oscillation that creates it.

17. How is the frequency of a wave related to its period?Frequency and period are inverses of one another. f = 1/T

18. How is the wavelength of a wave related to its frequency?Frequency and wavelength are inversely related. The longer the wavelength of a wave, the lower its frequency, and vice-versa.

19. How is the wavelength of a wave related to its amplitude?Wavelength is NOT related to amplitude.

20. Where do light waves travel fastest? Slowest?Light waves travel fastest in a vacuum. They travel slowest in substance with a high index of refraction, such as translucent solids.

21. Where do sound waves travel fastest? Slowest?Sound waves travel fastest through dense solids. They travel slowest through thin gases.

22. Compare the speed of light in a vacuum to the speed of sound in a dense solid. Light waves travel much faster than even the fastest sound waves.

23. Describe the Doppler Effect. Give a real-life example where the pitch would be lower to the observer, and one where the pitch would be higher to the observer, than the true pitch of the sound.The Doppler Effect is an apparent shift in pitch due to the relative motion between the observer of a sound and the source of the sound. EX: Hearing the pitch of an ambulance siren increase as it approaches you, and descrease as it moves away from you.

24. Find the velocity of a wave that has a wavelength of 4.5 m and a frequency of 0.25 Hz.

25. What is the wavelength of a wave with a velocity of 200 m/s and a frequency of 2800 Hz?

26. What is the frequency of a wave that oscillates once every four seconds?

27. A wave passes an ocean liner 6 times every 15 minutes. What is the frequency of the wave?

OPTICS

28. Define “focal point.”The focal point of a lens or mirror is where the light rays converge.

29. What type of image is formed by converging light rays?Convergin light rays form a real, inverted image.

30. What type of image is form by diverging light rays?Diverging light rays form a virtual, upright image.

31. Describe a real image.A real image is inverted and forms on the opposite side of a convex lens as the object.

32. Describe a virtual image.A virtual image is upright and forms on the same side of a convex lens as the object.

33. Describe the image formed by a plane mirror. Where is it located?A plane mirror forms an upright, virtual image that is NOT magnified (it is the same size as the object). The image is located behind the mirror, at the same distance as the object.

34. Fill in the table for images created by a convex lens.

OBJECT LOCATION IMAGE LOCATION DESCRIPTION/TYPE OF IMAGEOutside focal point Opposite side of lens Real, invertedInside focal point Same side of lens Virtual, upright, magnified

At focal point No image Doesn’t exist

ELECTRICITY & CIRCUITS

35. Complete the phrase: likes repel, opposites attract36. List the two types of charged particles. Give an example of each.

POSITIVELY charged – protonNEGATIVELY charged - electron

37. Define and draw a series circuit.A series circuit has only one path (loop) for the electrons to follow.

38. Define and draw a parallel circuit.A parallel circuit has two or more (multiple) paths for electrons to follow.

39. Complete the following table for series and parallel circuits.

TYPE # OF PATHS

BRIGHTNESS OF MULTIPLE BULBS COMPARED TO ONE BULB

WHAT HAPPENS IF ONE BULB GOES OUT

SERIES one Multiple bulbs much dimmer than single bulb All other bulbs go out

PARALLEL

two or more

Multiple Bulbs have equal brightness as single

Bulbs on other branches stay lit

40. If a series circuit containing one light bulb carries 2 A of current and is supplied with a voltage difference of 12 V, what is the resistance of the bulb?

41. What is the voltage of a circuit that has a total current of 6 A and a total resistance of 3 Ω?

42. In a series circuit, current is equal across the circuit.43. In a parallel circuit, voltage is equal in all branches of the circuit, and equal to the total

voltage. (same word in both blanks)44. Draw the symbols for each of the following circuit components: switch, battery,

lightbulb, resistor

45. Find the voltage drop across each resistor in the diagram.

46. How much power is used by a 12-V battery running a current of 20 A?

47. How much voltage is required to run a 60-W light bulb if it is on a 15-A circuit?

48. How much force exists between two particles, each with a charge of 1.4 x 10-5 C, if they separated by 3.2 m?

49. A 1-C charge and a 2-C charge are separated by 1000 m. What is the force between them?

MAGNETISM & ELECTROMAGNETIC INDUCTION

50. What do magnetic field lines represent?Magnetic field lines represent the lines of force surrounding a magnet.

51. Draw a picture of a magnet with its field lines, and give a real-life example of how you might observe these lines.You can observe magnetic field lines by placing a piece of paper over a magnet and sprinkling iron filings on the paper.

52. Describe how to create an electromagnet.To create an electromagnet, wrap a wire around an iron core (such as a nail) and attach both ends of the wire to a battery.

53. Give two examples of ways to change the strength of an electromagnet.To change the strength of an electromagnet, you can either change the number of loops of wire around the iron core or change the current flowing through the wire. Both changes directly change the strength of the electromagnet.

MODERN PHYSICS

54. Describe the two fundamental forces that are responsible for holding atoms together.The two fundamental forces that hold atoms together are the strong nuclear force and the weak nuclear force.

55. What is meant by the phrase “the dual nature of light,” or “wave-particle duality”?The phrases “dual nature of light” and “wave-particle duality” refers to the fact that light can behave both as a wave and as a particle.

56. Describe how light can behave as both a wave and as a particle.Light can behave as a wave because it can travel through a vacuum and exhibits wave behaviors such as reflection, refraction, diffraction, & interference. Light can behave as a particle as demonstrated by the photoelectric effect.

57. What is the photoelectric effect?The photoelectric effect is the observation that, when a high-frequency light strikes certain types of metal, it causes electrons to be ejected from the metal’s surface.

58. How is the energy of a photon of light related to its frequency?The energy of a photon is related to its frequency by Planck’s constant.

59. Using the photoelectric effect, describe how increasing the energy or frequency of a photon changes the way electrons are ejected from a sheet of metal.As the energy and frequency of a photon increases, the speed of the ejected electrons increase as well.

60. Using the photoelectric effect, describe how increasing the intensity of a beam of photons changes the way electrons are ejected from a sheet of metal.As the intensity of a beam increases, the number of electrons ejected from the metal increases.