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

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

The correct answer is: 500 blank H z


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

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