When a sound wave is reflected from a wall the phase difference between the reflected and incident pressure wave is:

Options

A. `0`
B. `pi`
C. `pi//2`
D. `pi//4`

Answer

A

Explanation

When a sound wave gets reflected from a rigid boundary, the particles at the boundry are unable to vibrate. Thus, a reflected wave is generted which interferes with the incoming wave to produce zero displacement at the rigid boundary. At these points (zero displacement), the pressure variation is maximum. Thus, a reflected pressure wave has the same phase as the incident wave.