What happens to the perceived frequency when both the source and the listener move with the same speed in the same direction?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. It remains unchanged.
According to the Doppler Effect, the perceived frequency of a wave changes only when there is relative motion between the source and the listener. When both move with the identical speed (vs = vL) in the same direction, the relative velocity between them is zero. The distance between them remains constant, meaning the wave crests reach the listener at the same rate they are emitted. Consequently, the listener hears the original frequency without any shift in pitch.