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

As we learnt in

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

- wherein

speed of sound

speed of source

original frequency

apparent frequency

Here observer is stationary and source is moving towards observer

= 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.