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A source of sound of frequency 900 cycles/sec is moving towards a stationary observer with 34 m/sec speed. If the speed of sound is 340 m/sec, then the apparent frequency will be

  • Option 1)

    500 cycles / sec

  • Option 2)

    1000 cycles / sec

  • Option 3)

    1200 cycles / sec

  • Option 4)

    900 cycles / sec

 

Answers (1)

best_answer

As we learnt in

Frequency of sound when observer is stationary and source is moving towards observer -

\nu {}'= \nu _{0}.\frac{C}{C-V_{s}}
 

- wherein

C= speed of sound

V_{s}= speed of source

\nu _{0}= original frequency

\nu {}'= apparent frequency

 

 Here observer is stationary and source is moving towards observer

\Rightarrow \nu=\nu_{0}.\frac{c}{c-v_{s}}=900\times \frac{340}{340-34}=900\times \frac{340}{304}

= 1000 cycle/s

 


Option 1)

500 cycles / sec

This option is incorrect.

Option 2)

1000 cycles / sec

This option is correct.

Option 3)

1200 cycles / sec

This option is incorrect.

Option 4)

900 cycles / sec

This option is incorrect.

Posted by

divya.saini

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