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KVPY2010PhysicsWaves and Sound

A bus driving along at 39.6 kmph is approaching a person who is standing at the bus stop, while honking repeatedly at an interval of 30 seconds. If the speed of the sound is 330 ~m / s , at what interval will the person hear the horn?

Options

  1. A31 seconds
  2. B29 seconds
  3. C30 seconds
  4. Dthe interval will depend on the distance of the bus from the passenger

Correct answer

B. 29 seconds

Step-by-step solution

v =39.6 ~km / hr =11 ~m / s , t ₁= d 330 and t ₂= d -11 30 330 Now t=t₁-t₂=1 now t₁=30 sec t₂=29 sec

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