Which of these waves will diffract the most when passing through a 20 cm wide opening in a barrier?
a. a wave with a wavelength of 25 cm
b. a wave with a wavelength of 2 cm
c. a wave with a wavelength of 0.05 cm
d. none of these waves will diffract at all
[Ques. 2] You can hear sound through an open window from sources that are not in your line of sight because of
a. interference
b. diffraction
c. the sound level
d. the Doppler effect
e. none of the above
[Ques. 3] If the source moves, the wavelength of the sound in front of the direction of motion is ____________ the wavelength behind the direction of motion.
a. the same as c. smaller than
b. larger than d. unrelated to
[Ques. 4] A source emits sound at a fixed constant frequency f. If the source moves away from you faster than the speed of sound in air, the frequency that you hear is
a. the same as f c. lower than f
b. higher than f d. unrelated to f
[Ques. 5] A source emits sound at a fixed constant frequency f. If the temperature of the air rises, the frequency you hear is
a. the same as f c. lower than f
b. higher than f d. unrelated to f
[Ques. 6] A source emits sound at a fixed constant frequency f. If the source moves away from you, and at the same time you run away from the source, the frequency you hear is
a. the same as f c. lower than f
b. higher than f d. unrelated to f
[Ques. 7] A source emits sound at a fixed constant frequency f. If you run towards the source, the frequency you hear is
a. the same as f c. lower than f
b. higher than f d. unrelated to f
[Ques. 8] A source emits sound at a fixed constant frequency f. If the source moves away from you, the frequency you hear is
a. the same as f c. lower than f
b. higher than f d. unrelated to f
[Ques. 9] You shout at a cliff, and hear your echo in 2 seconds. If the speed of sound in the air is 340 m/s, the distance of the cliff from you is
a. 85 m
b. 170 m
c. 340 m
d. 680 m
e. none of the above
[Ques. 10] A wave moves in a rope with a certain wavelength. A second wave is made to move in the same rope with twice the wavelength of the first wave. The frequency of the second wave is _______________ the frequency of the first wave.
a. 1/2 c. 2 times
b. the same as d. unrelated to
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