A siren emitting sound of frequency 1000 Hz approaches a stationary observer at one-half the speed of sound.The observer hears a frequency of
A)1000 Hz
B)2000 Hz.
C)500 Hz.
D)1500 Hz.
E)none of the above.

Question

Quizplus · Accepted Answer

When the source approaches the observer, the frequency increases. Using the Doppler effect formula for sound, the observed frequency is doubled when the source moves at half the speed of sound towards the observer.

A Siren Emitting Sound of Frequency 1000 Hz Approaches a Stationary