(Multiple choice)

(1)

A traveling wave passes a point of observation. At this point, the time between successive crests is 0.2 s. Which of the following is true? 

(a) The wavelength is 5 m. 

(b) The frequency is 5 Hz. 

(c) The velocity of propagation is 5 m/s. 

(d) The wavelength is 0.2 m. 

(e) There is not enough information to justify any of these statements.

(2) True or false: 

The energy in a wave is proportional to the square of the amplitude of the wave.

(3) True or false: 

A 60-dB sound has twice the intensity of a 30-dB sound.

(4)

Two sounds differ by 30 dB. The intensity of the louder sound is I_L and that of the softer sound is I_S. The value of the ratio I_L/I_S is 

(a) 1000. 

(b) 30. 

(c) 9. 

(d) 100. 

(e) 300.

(5)

The frequency of a car horn is f₀. What frequency is observed if both the car and the observer are at rest, but a wind blows toward the observer? 

(a) f₀ 

(b) Greater than f₀ 

(c) Less than f₀ 

(d) It could be either greater or less than f₀. 

(e) It could be f₀ or greater than f₀, depending on how wind speed compares to speed of sound.

(6)

A wave pulse travels along a light string that is attached to a heavier string in which the wave speed is smaller. The reflected pulse is _____, and the transmitted pulse is _____. 

(a) Inverted/inverted 

(b) Inverted/not inverted 

(c) Not inverted/not inverted 

(d) Not inverted/inverted 

(e) Nonexistent/not inverted

(7) True or false: 

(a) Wave pulses on strings are transverse waves. 

(b) Sound waves in air are transverse waves of compression and rarefaction. 

(c) The speed of sound at 20°C is twice that at 5°C.

(8)

Sound travels at 340 m/s in air and 1500 m/s in water. A sound of 256 Hz is made under water. 

In the air, the frequency will be 

(a) The same, but the wavelength will be shorter. 

(b) Higher, but the wavelength will stay the same. 

(c) Lower, but the wavelength will be longer. 

(d) Lower, and the wavelength will be shorter. 

(e) The same, and the wavelength too will stay the same.