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AP EAMCET2005PhysicsWaves and Sound

A vehicle sounding a whistle of frequency 256 ~Hz is moving on a straight road, towards a hill with a velocity of 10 ~ms ⁻¹ . The number of beats per second observed by a person travelling in the vehicle is velocity of sound =330 ~ms ⁻¹

Options

  1. Azero
  2. B10
  3. C14
  4. D16

Correct answer

D. 16

Step-by-step solution

Apparent frequency heard by the observer, aligned n^ & = ( v+v_s v-v_s ) n & = ( 330+10 330-10 ) 256 & = 340 320 256=272 ~Hz aligned Number of beats heard by the observer =272-256=16

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