Question

A car is moving towards a high cliff. The driver sounds a horn of frequency f. The reflected sound heard by the driver has frequency 2f. If v is the velocity of sound, then the velocity of the car, in the same velocity units, will be

(a) v/√2

(b) v/3

(c) v/4

(d) v/2

Answer 1

Correct option  (b) v/3

Explanation:

1 st the car is the source and at the cliff, one observes f'.

2nd cliff is now source. It emits frequency.f' and the observer is now the driver who observes f'.