Question

A wave is going from one medium to another, then which of its property may / must change ?

• A. Frequency
• B. Wavelength
• C. Velocity
• D. Amplitude

Answer 1

Answer: (B), (C), (D)

The correct options are
B Wavelength
C Velocity
D Amplitude

Frequency is the property of source while velocity is the property of medium and wavelength is the property of both medium and source. So, wavelength and velocity of the wave must change as the medium change, while the frequency remains the same . On the boundary, some absorption can be there, as a result the amplitude (and hence intensity) can decrease as the medium changes.
Amplitude will either decrease or remain the same but it can never increase due to change in medium (assuming no external source is providing energy).