Physics · Wave motion, longitudinal and transverse waves, speed of the travelling wave, displacement relation for a progressive wave

When a sound is going away from a stationary observer with the velocity equal to

When a sound is going away from a stationary observer with the velocity equal to that of sound in air, then the frequency heard by observer is n times the original frequency. The value of n is

  • A. 0.5
  • B. 0.25
  • C. 1.0
  • D. no sound is heard

Step-by-step solution

Using the Doppler effect formula for a source moving away from a stationary observer: f' = f * v / (v + v_s). Given v_s = v, we get f' = f * v / (2v) = f/2. Thus n = 0.5.
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