1-3. A transverse wave travels along an infinitely long horizontal string at 140 m/s. As the wave passes each point on the string, each piece of string executes simple harmonic motion with a frequency of 35 Hz and an amplitude of 7 cm.
1. The number of wave crests passing a point on the string each second is called the
a) frequency. b) amplitude. c) wavelength. d) period. e) speed.
2. The distance between successive wave crests is __________ m.
a) 7 b) 140 c) 35 d) 0.25 e) 4
3. When the frequency of the wave increases, the speed of the wave
a) remains the same. b) increases. c) could increase or decrease. d) decreases.
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4. When the amplitude of a sound wave is doubled, the intensity of the wave = _____ x original intensity.
a) 1/4 b) 1/2 c) 2 d) 4 e) 1
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5-6. The velocity of propagation of a transverse wave traveling along a 2-m long string fixed at both ends is 200 m/s. Standing waves are set up in the string.
5. The wavelength of the fundamental frequency of this string is _____ m.
a) 0.5 b) 4 c) 1 d) 8 e) 2
6. Which one of the following is not a resonant frequency of this string?
a) 200 Hz b) 25 Hz c) 50 Hz d) 100 Hz
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7. Figure #1 shows a standing wave pattern in a 2 m long organ pipe. The frequency of this standing wave is _____ Hz.
a) 43 b) 214 c) 429 d) 258 e) 129
8. A tuning fork of unknown frequency is sounded along with a tuning fork with a frequency of 256 Hz and three beats/second are heard. The unknown frequency must be ________.
a) 253 Hz b) either 253, 256, or 259 Hz c) 256 Hz
d) 259 Hz e) either 253 or 259 Hz
9. A jet aircraft 5traveling at ½ of the velocity of sound emits a 1000 Hz roar as it "buzzes" an airport control tower. As it is traveling away, the traffic controller hears a _____ Hz roar.
a) 2000 b) 1000 c) 500 d) 1500 e) 667
10. Wow! Did I really learn about all this stuff this quarter? I deserve _____ points for surviving.
a) zero b) no c) -5 d) +5 !!!! e) 0
11. A glass rod rubbed with a piece of silk acquires a positive charge. The piece of silk
a) loses electrons. b) acquires electrons. c) remains electrically neutral.
d) loses protons. e) acquires protons.
12. A distance of 3 m separates a +2 C and a +8 C charge. At what point on a line between these charges will a -2 C charge experience no electrostatic force?
a) 1 m from the +8 C charge. b) 1 m from the +2 C charge.
c) No such point exists. d) 3/5 m from the +2 C charge.
e) 3/5 m from the +8 C charge.
13. Four of the following statements about electrostatic field lines are true and one is false. Select the FALSE statement.
a) Have tangents in the direction of E.
b) Are close together where the electric field is large.
c) Follow along equipotential surfaces.
d) Start on positive charges and end on negative charges.
e) Point from high voltages regions to low voltage regions.
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14-15. It takes 10 J of energy (a force of 20 N acting through a distance of 50 cm) to move 2 C of charge from point A to point B.
14. The potential difference between points A and B, VB – VA, is _____ V.
a) 2 b) 10 c) 5 d) 20 e) 0.2
15. The magnitude of the electric field E in the region between points A and B is _____ N/C.
a) 20 b) 40 c) 10 d) 25 e) 5
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16. A knob on a transformer in an electrical power station is +1000 V above ground potential. An electron released near the knob will
a) move around in circles and be confused just like me. b) move toward the knob.
c) move away from the know d) remain stationary.
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17-20. Figure #2 shows an equilateral triangle with three equal 10 cm long sides and three equal 600 internal angles. Charges of +2 micro-C are located at two corners.
17. The magnitude of the electric field E at the third corner is _____ x 106 N/C.
a) 0.31 b) 0.36 c) 3.1 d) 3.6 e) 1.8
18. The electric field E at the third corner points in the direction of
a) A b) B c) C d) D e) nonsense, it has no direction
19. The potential V at the third corner is _____ x 106 V.
a) 0.31 b) 0.18 c) 0.36 d) 3.6 e) 1.8
20. The potential V at the third corner points in the direction of
a) A b) B c) C d) D e) nonsense, it has no direction
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