CHAPTER 19

QUIZ 8

CHAPTER 19

1. How far in terms of wavelength does the crest of a wave travel in 10 periods?

a. 1/10 of a wavelength

b. 20 wavelengths

c. 10 wavelengths

d nota

2. The vibrations of a transverse wave move in a direction

a. along the direction of motion of the wave

b. at right angles to the direction of motion of the wave

c. nota

3.The vibrations of a longitudinal wave move in a direction

a. along the direction of motion of the wave

b. at right angles to the direction of motion of the wave

c. nota

4. A transverse wave has wavelength 0.25 m and the frequency is 8 cycles per second. The wave speed is

a. 1/4 m/s

b. 8 m/s

c. 4 m/s

d. 1/8 m/s

e. nota

5. True or False. A standing wave can be thought of as the sum of two waves moving in the same direction.

a. True

b. False

6 In a transverse standing wave, a node is a position of

a. zero or minimal transverse displacement

b. maximum transverse displacement

7. A railroad locomotive is at rest with its whistle blowing and starts moving away from you . The frequency that you hear will

a. increase

b. decrease

c. will not change

8. In the previous problem, the wavelength reaching your ear will

a. increase

b. decrease

c. remain the same

9. Assuming the wave speed remains the same, when the frequency of a wave increases, the wavelength

a. decreases

b. increases

c. remains the same

CHAPTER 20

10. A sound wave is

a. a longitudinal wave

b. a transverse wave

c. always a standing wave

d. nota

11. Sound travels fastest in

a. air

b. water

c. steel

d. a vacuum

e. nota

12. The speed of a sound wave in air depends on

a. its frequency

b. its wavelength

c. the air temperature

d. nota

13. Sound travels faster in air if the air temperature is (a) warm* (b) cold (c) average

FOR BACKGROUND ON THE FOLLOWING PROBLEM, READ PAGE 359-361, WITH AN EYE ON RESONANCE. When you feed a system with energy at the natural frequency, the amplitude of vibrations grows large, to the point where the motion surpasses the elastic limit and the structure comes apart. See figure 20.15 of the Tacoma Narrows Bridge.

14. The natural frequency of an empty wine glass is 256 Hz. The glass will resonate if the vibrating force due to the sound of a nearby opera singer is (a) 512 Hz (b) 256 Hz* (c) 1024 Hz (d) nota

Chapter 22 and 20.

15.What force binds atoms together to form molecules ?

a. gravitational

b. nuclear

c. none of the above

16. When you rub an inflated balloon in your hair, you have an example of charging by

a. contact

b. friction

c. induction

d. none of the above

17. After rubbing it in my hair, if I placed the inflated balloon of the previous problem against the classroom wall and it sticks . Why did the balloon stick to the wall?

a. The positively charged balloon polarized atoms in the wall and created a negatively charged surface on the wall that attracted the balloon

b.. The negatively charged balloon polarized atoms in the wall and created a positively charged surface on the wall that attracted the balloon.

c. nota

18. Electrical forces are different from gravitational forces because electrical forces

a. attract or repel

b. obey the inverse square law

c. nota

19. The magnitude of the electric force between two charges depends only on the

a. the product of the masses of the two charges

b. the product of the magnitude of the two charges

c. the product of the magnitude of the two charges and the separation distance

d. the separation distance and the product of the masses of the two charges

e. nota

20. An electron and a proton

a. attract each other

b. repel each other

c. neither attract or repel each other

21.Two charges separated by 3 meters repel each other with a 1-N force on each other. The two charges

a. are of the same sign

b. are of opposite signs

c.nota

22. In the previous problem, if the magnitude of each charge is doubled, then the force on each charge will be

a. 3 N

b. 9 N

c. 1 N

d. 4 N

e. nota

23. In problem 21, if the two charges are pulled to a separation distance of 6 meters, the force of attraction on each other will be

a. 1-N

b. 1/2 N

c. 1/4 N

d. 2 N

e. nota

24. Suppose that the strength of the electric field at a certain distance from an isolated point charge has a value of 4 N/C . If the distance is doubled, then the electric field will have the value

a. 4 N/C

b. 1 N/C

c. 1/2 N/C

d. nota

25. Suppose you place a free proton in an electric field that points vertically up. The electric force on the proton will point

a. up

b. down

26. Suppose you place a free electron in an electric field that points vertically up. The electric force on the electron will point

a. up

b. down

27. Suppose you expend 40 Joules of work to push an 8-coulomb positive test charge in a direction opposite (against) an electric field. What is the gain in potential energy of the test charge?

a. 80 Joules

b. 40 Joules

c. 5 Joules

28. In the previous problem, what is the change in potential between the test charge's initial location and the test charge's final location?

a. 80 Volts

b. 16 Volts

c. 5 Volts

d. nota

29. The net charge of a fully charged capacitor is

a. positive

b. negative

c. none of the above

30. The net charge of a fully discharged capacitor is

a. positive

b. negative

c. none of the above

31. True or False. The energy stored in a capacitor is stored in the electric field between the plates.
a. True

b. False

CH. 20

32. A pair of speakers on two sides of a stage are emitting identical pure tones of a fixed frequency and fixed wavelength in air. When you stand in the center aisle exactly equally distance from the two speakers you hear the sound loud and clear at maximum intensity but when you step to one side the sound reduces considerably in intensity. This reduction in intensity is an example of

(a) destructive interference. (b) constructive interference

33. In the previous problem , when continue to step in the same direction, the sound increases considerably to maximum intensity again. The is increase in intensity is an example of

(a) destructive interference. (b) constructive interference

34. Two sound waves can produces beats if they have

(a) the same frequency (b) different frequencies.