A siren of frequency 3.20 kHz moves away from a stationary observer with a speed of 30.5 m/s.If the speed of sound is 335 m/s,the frequency heard by the observer is
A)2.66 kHz
B)2.93 kHz
C)3.49 kHz
D)3.52 kHz
E)3.84 kHz

Question

Quizplus · Accepted Answer

The frequency heard by the observer can be calculated using the Doppler effect formula for sound: $ f' = \frac{f \cdot (v)}{v + v_s} $, where $ f $ is the source frequency (3.20 kHz), $ v $ is the speed of sound (335 m/s), and $ v_s $ is the speed of the source (30.5 m/s). Plugging in the values, the observed frequency $ f' $ is approximately 2.93 kHz.

A Siren of Frequency 3