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MHT CET202611 April 2026Evening ShiftPhysicsWaves and SoundActual

A source of sound is moving towards a stationary observer with velocity ' V_S ' and then moves away with velocity ' V_S '. Assume that medium through which the sound waves travel is at rest. If 'V' is the velocity of sound and 'n' is the frequency emitted by the source then the difference between the apparent frequencies heard by the observer is

Options

  1. A2nVV_s V^2 - V_s^2
  2. BnVV_s V^2 - V_s^2
  3. CnVV_s V_s^2 + V^2
  4. D2nVV_s V_s^2 + V^2

Correct answer

A. 2nVV_s V^2 - V_s^2

Step-by-step solution

Apparent frequency when the source moves towards the stationary observer is given by n₁ = n ( V V - V_s ) Apparent frequency when the source moves away from the stationary observer is given by n₂ = n ( V V + V_s ) The difference between the apparent frequencies is n = n₁ - n₂ n = n ( V V - V_s ) - n ( V V + V_s ) n = nV ( 1 V - V_s - 1 V + V_s ) n = nV ( V + V_s - (V - V_s) V^2 - V_s^2 ) n = 2nVV_s V^2 - V_s^2 Answer: 2nVV_s V^2 - V_s^2

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