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Question

An engine is moving on a circular track with a constant speed. It is blowing a whistle of frequency 500 Hz. The frequency received by an observer standing stationary at the centre of the track is

  1. 500 Hz    
  2. More than 500 Hz    
  3. Less than 500 Hz    
  4. More or less than 500 Hz depending on the actual speed of the engine    

The correct answer is: 500 Hz


    Since there is no relative motion between the source and listener, So apparent frequency equals original frequency.

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