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MHT CET202016 Oct 2020Evening ShiftPhysicsWaves and SoundActual

An obstacle is moving towards the source with velocity 'v'. The sound is reflected from the obstacle. If ' c ^ is the speed of sound and ^ ' is the wavelength, then the wavelength of the reflected wave ( _ r ) is

Options

  1. A_ r = ( c-v c+v )
  2. B_ r = ( c-v c )
  3. C_ r = ( c+v c-v )
  4. D_ r = ( c+v c )

Correct answer

A. _ r = ( c-v c+v )

Step-by-step solution

The frequency of reflected sound wave is f_ r =f ( c+v c-v ) No change in velocity occurs due to reflection of sound wave. Hence, array l c _ r = c ( c+v c-v ) 1 _ r = 1 ( c+v c-v ) _ r = c-v c+v array

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