When a source of sound approaches, measurements will show an increase in the sound's
A)speed,
B)frequency,
C)wavelength,
D)all of these,
E)none of these,
And when a source of sound recedes, measurements will show an increase in the sound's
F)speed.
G)frequency.
H)wavelength.
I)all of these.
10)none of these.

Question

Quizplus · Accepted Answer

When a source of sound approaches, the frequency of the sound waves increases, which corresponds to an increase in pitch. This means that choice B is correct. At the same time, the wavelength of the sound waves decreases, which means that there will be a higher compression rate of waves and hence the sound will appear to be louder. This corresponds to a decrease in wavelength, which means that choice H is incorrect.
When a source of sound recedes, the opposite effect takes place, i.e, the frequency decreases and the wavelength increases. This corresponds to a decrease in pitch and a lowering of the sound's volume respectively, which means that choice H is correct. Speed of sound is constant in a given medium, so choice F and D are incorrect. Therefore, the correct choices are B and H.

When a Source of Sound Approaches, Measurements Will Show an Increase