Question

Sound waves from a loud bass guitar are represented below approaching a soundproof barrier as view from the above. The barrier has opening as shown, which is narrower than the wavelength of the sound waves. Five locations are shown on the side of the barrier opposite the bass guitar.
A person at which location (s) would hear the sound and why?

• A. 3 only; sound waves are completely chopped off
• B. 2, 3 and 4 only; refraction
• C. all locations ; refractions
• D. all locations; diffraction
• E. all locations; Doppler effect

Answer 1

Answer: (D)

all locations; diffraction

The necessary condition for diffraction is that wavelength of wave should be comparable to the size of opening , this condition is fulfilled in the given question as size of opening is narrower than wavelength therefore diffraction will takes place here and due to this person will hear sound at all locations .