Question

A small vibrating object on the surface of a ripple tank is the source of waves of frequency 20 Hz and speed 60 cm/. If the source is moving to the right, as shown, with speed 20 cm/*, at which of the labeled points will the frequency measured by a stationary observer be greatest?

(A) A

(B) B

(C) C

(D) D

(E) It will be the same at all four points.

Answer 1

The correct option is: (C) C

Explanation:

Clearly at point C the waves are compressed so are more frequent.