CRT practice test
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- Light bulbs in series all carry the same current regardless of resistance. - Electromagnetic waves are transverse waves that include visible light, radio waves, and x-rays. - Light sometimes acts as both a wave and a particle. - Newton's 3rd law states that whenever one object exerts a force on a second object, the second object always exerts the same amount of force back on the first.
CRT practice test
- 1. T/F Light bulbs connected in series all carry the same current, regardless of their resistances. TRUE
- 2. When connected to a 120-volt power supply, how much current exists in a light bulb that has a resistance of 240 ohms? a. 28,800 A b. 240 A c. 120 A d. 0.5 A d. 0.5 A
- 3. If two negative charges are held close together and then released, the charges will a. accelerate toward each other. b. accelerate away from each other. c. move at a constant speed away from each other. d. not move. b. accelerate away from each other
- 4. T/F Most of the electromagnetic spectrum consists of Visible Light? False
- 5. Electromagnetic waves are a. transverse waves. b. longitudinal waves. a. Transverse
- 6. Which of the following is NOT an electromagnetic wave? a. Sound b. Radio c. Light d. X-ray a. Sound
- 7. T/F Light sometimes acts as a wave and sometimes as a particle. True
- 8. If you accidentally grabbed the prongs of a partially plugged-in 120- V electrical plug on a day when your skin resistance was 120,000 ohms, how much current would pass through your body? a. 12,000,000 A b. 1000 A c. 120 A d. 0.001 A d. 0.001A
- 9. A small, positively charged object near a positively charged sphere is moved closer to the sphere. The electrical potential energy of the small object a. increases. b. decreases. c. stays the same. a. increases
- 10. When one light bulb in a series circuit containing several light bulbs burns out, a. the other light bulbs burn brighter. b. nothing changes in the rest of the circuit. c. none of the other bulbs will light up. c. none of the other bulbs will light up.
- 11. A 38-kg boy is rollerskating at a speed of 1.8 m/s when he bumps against a box. The box slows the boy’s speed to 1.2 m/s in 0.40 s. What is the force of the boy against the box? a. 68.4N b. 45.6N c. 57N d. 15.2N c. 57N
- 12. A 2.0-kg book is on a shelf that is 1.6 m high. What is the gravitational potential energy of the book relative to the ground? a. 3.21N b. 31.39J c. 31.39N b. 31.39J
- 13. An object that has kinetic energy must be a. moving. b. falling. c. elevated. d. at rest. a. moving
- 14. “Energy can neither be created or destroyed” is an example of a. a scientific hypothesis b. a theory c. a scientific law d. an outdated idea c. a scientific law
- 15. T/F The unit of electric potential is the joule. False
- 16. T/F Sound can travel through solids, liquids, gases, and even a vacuum. False
- 17. Compared to the speed of light, sound travels a. faster b. slower c. about the same b. slower
- 18. A Skater at the top of a 30m-high hill prepares to go down. He wants to estimate his speed at the bottom of the hill. The skater’s mass is 95kg. How fast would he be going? a. 42.75 m/s b. 43.17 m/s c. not enough information b. 43.17 m/s
- 19. Electromagnetic waves have characteristics of a. amplitude, frequency, compression s b. wavelength, trough, period c. rarefraction, speed, trough d. amplitude, longitude, node b. wavelength, trough, period
- 20. Suppose the gravitational force between two massive balls is 10 N. If the distance between the balls is cut in half, what is the force between the masses? a. 20N b. 5N c. 2.5N d. 40N d. 40N
- 21. The speed of sound in dry air at 20 degrees Celsius is 340 m/s. How far away is a jet plane when you notice a 2-second delay between seeing the plane and hearing it? a. 6800 m b. 40 m c. 340 m d. 680 m d. 680 m
- 22. An arrow in a bow has 70 J of potential energy. Assuming no energy loss, how much kinetic energy will it have after it has been shot? a. 2450 J b. 140 J c. 70 J c. 70 J
- 23. T/F Whenever one object exerts a force on a second object, the second object always exerts the same amount of force back on the first object. True
- 24. T/F A rocketship can work in space because of Newton’s 3rd Law. True
- 25. In an alternating current circuit, electron flow is a. slower than a snail’s pace. b. almost the speed of light. c. simply back and forth, going nowhere. c. simply back and forth, going nowhere.
- 26. A heavy-weight boxer’s punch measures 12000N. Can the boxer punch a sheet of paper with all this force? a. no, the paper limits his force b. yes, but the impact is limited by the paper’s weight c. no, Newton’s 2nd law prohibits it d. yes, the paper accelerates with 12000N b. yes, but the impact is limited by the paper’s weight
- 27. When one light bulb in a parallel circuit containing several light bulbs burns out, a. the other light bulbs burn brighter. b. nothing changes in the rest of the circuit. c. none of the other bulbs will light up. b. nothing changes in the rest of the circuit.
- 28. A woman weighing 500 N sits on the floor. She exerts a force on the floor of a. 50.96 b. 50.96 N c. 500 N d. 227 lb e. 50 N c. 500 N
- 29. A 60-kg person on in-line skates pushes against a wall with a force of 30 N and recoils. What acceleration does that person experience? a. 2 m/s2 b. 0.5 m/s2 c. ½ d. 90 V b. 0.5 m/s2
- 30. If Skelly the skater’s speed is increased so he has twice the momentum, then his kinetic energy is increased by a. 8 b. 1/2 c. 2 d. 4 d. 4
- 31. T/F If a bicycle and a parked car have a head-on collision, the force of impact is greater on the bicycle. False
- 32. If you were to weigh yourself in an elevator that is accelerating upward, compared to your ordinary weight you would weigh a. more than normal b. the same c. less, but more than zero d. zero a. more than normal
- 33. Imagine you are standing atop a ladder so tall that you are 3 times as far from Earth’s center. What would be your weight at the top, relative to your weight at the surface? a. 3 times more b. 1/3 times less c. 1/9 as much d. 9 times more c. 1/9 as much
- 34. T/F When you turn on a light, electrons move at speeds near the speed of light in order to light up the light bulb. True
- 35. If a horse pulls on a wagon at rest, the wagon pulls back equally as much on the horse. Will the wagon be set into motion? a. yes, because there is a net force on the wagon b. yes because the horse’s pull on the wagon is greater than the wagon’s pull on the horse c. no, the forces cancel each other a. yes, because there is a net force
- 36. T/F A good reflector of heat is a poor absorber of heat. True
- 37. Heat transfer by conduction occurs when a. electrons bump into other atoms and other electrons b. large number of atoms move from place to place c. when atoms give off heat in the form of Electromagnetic waves d. when Electromagnetic waves travel in a vacuum a. electrons bump into other atoms and other electrons
- 38. A closed circuit is a circuit in which current a. can flow. b. is prevented from flowing. a. can flow
- 39. The gravitational field strength near the center of Earth is a. less than on the surface b. equal as on the surface c. zero d. more than on the surface d. more than on the surface
- 40. Current from a battery is a. DC. b. AC. a. DC
- 41. When resistors are put in series next to each other, their overall resistance is a. larger than that of an individual resistor. b. the same as the resistance of one of the resistors. c. smaller than the resistance of any of the resistors. a. larger than that of an individual resistor.
- 42. The reason you can hold your fingers beside a candle flame without getting hurt is that a. air is a poor heat conductor b. hot air rises c. cool leaves your fingers into the candle a. air is a poor heat conductor
- 43. Heat is measured in a. calories b. kilocalories c. Joules d. all of the above d. all of the above
- 44. T/F The rate at which work is done is called Power True
- 45. T/F Objects only move when a force is exerted True
- 46. What is the ground speed of a bird flying at 3.0 m/s when there is a 4.0 m/s crosswind? a. 3.0 m/s b. 4.0 m/s c. 5.0 m/s d. 9.0 m/s c. 5.0 m/s