Question

Four light sources produce the following four waves:
$y _{1}= a \sin \left(\omega t+\phi_{1}\right)$
$y_{2}=a \sin 2 \omega t$
$y_{3}=a' \sin \left(\omega t+\phi_{2}\right)$
$y _{4}= a' \sin (3 \omega t+\phi)$
Superposition of which two waves give rise to interference?

• A. (i) and (ii)
• B. (ii) and (iii)
• C. (i) and (iii)
• D. (iii) and (iv

Answer 1

Answer: (C)

Interference phenomenon takes place between two waves which have equal frequency and propagate in same direction.
Hence,$y_{1}=a \sin \left(\omega t+\phi_{1}\right) $
$y_{3}=a^{'} \sin \left(\omega t+\phi_{2}\right)$
will give rise to interference as the two waves have same frequency $\omega$.