# P102HW3 ```Physics 102-001 Homework #3
with extra credit (23 points possible)
Due date: 3 May 2012 (but you can turn it in earlier)
NAME: _____________________________________________________
1) Which of the following is not a transverse wave?
A) sound
B) light
D) all of these
E) none of these
2) The vibrations of a transverse wave move in a direction
A) along the direction of wave travel.
B) at right angles to the direction of wave travel.
C) that changes with speed.
3) The vibrations of a longitudinal wave move in a direction
A) along the direction of wave travel.
B) at right angles to the direction of wave travel.
C) that changes with speed.
4) Like a transverse wave, a longitudinal wave has
A) amplitude, frequency, wavelength, and speed. B) amplitude, frequency, and wavelength.
C) amplitude, wavelength, and speed.
D) wavelength, speed, and frequency.
E) amplitude, frequency, and speed.
5) How many vibrations per second are associated with a 101-MHz radio wave?
A) less than 101,000,000
B) 101,000,000
C) more than 101,000,000
6) The frequency of a simple pendulum depends on
A) its mass.
B) its length.
C) both of these
D) neither of these
7) If the frequency of a certain wave is 10 hertz, its period is
A) 0.1 second.
B) 10 seconds.
C) 100 seconds.
D) None of the above.
8) The source of every sound is something that is
A) vibrating.
B) moving.
C) accelerating.
D) undergoing simple harmonic motion.
E) a net emitter of energy.
9) To say that electric charge is conserved is to say that electric charge
A) may occur in an infinite variety of quantities.
B) is a whole number multiple of the charge of one electron.
C) will interact with neighboring electric charges.
D) can be neither created nor destroyed.
E) is sometimes negative.
10) A main difference between gravitational and electric forces is that electrical forces
A) attract.
B) repel or attract.
C) obey the inverse-square law.
D) act over shorter distances.
E) are weaker.
11) An electron and a proton
A) attract each other.
B) repel each other.
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C) neither attract nor repel each other.
12) When the distance between two charges is halved, the electrical force between the charges
B) doubles.
C) halves.
D) is reduced by 1/4.
E) None of the above choices are correct.
13) The source of all magnetism is
A) tiny pieces of iron.
B) tiny domains of aligned atoms.
D) moving electric charge. E) none of these
C) ferromagnetic materials.
14) If a steady magnetic field exerts a force on a moving charge, that force is directed
A) opposite the motion.
B) in the direction of the motion.
C) at right angles to the direction of the motion.
15) Superconducting electromagnets
A) exist now.
C) may be possible in the distant future.
16) Voltage can be induced in a wire by
A) moving the wire near a magnet.
C) changing the current in a nearby wire.
E) None of the above choices are true.
B) may be possible in the near future.
D) are science fiction.
B) moving a magnet near the wire.
D) Choices A, B, and C are all true.
17) Most of the waves in the electromagnetic spectrum are
A) red light.
B) blue light.
C) green light.
D) invisible.
18) Electromagnetic waves consist of
A) compressions and rarefactions of electromagnetic pulses.
B) oscillating electric and magnetic fields.
C) particles of light energy.
D) high-frequency gravitational waves.
19) Compared to ultraviolet waves, the wavelength of infrared waves is
A) shorter.
B) longer.
C) the same.
20) Which of the following is fundamentally different from the others?
A) sound waves
B) X-rays
C) gamma rays
D) light waves
21) Sunburns are produced by
A) ultraviolet light.
B) visible light.
D) all of these
E) none of these
C) infrared light.
22) Color depends on what characteristic of light?
A) its frequency (or wavelength)
B) its amplitude
C) both of these
23) The sky is blue because air molecules in the sky act as tiny
A) mirrors which reflect only blue light.
B) resonators which scatter blue light.
C) sources of white light.
D) prisms.
E) none of these
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