Question

Four light waves are represented by :-
$\left(i\right)y=a_{1}sin\left(3 \omega t\right)$
$\left(ii\right)y=a_{2}sin\left(\omega t + \phi\right)$
$\left(iii\right)y=a_{1}sin\left(2 \omega t\right)$
$\left(iv\right)y=a_{2}sin\left[\right. 2 \left(\omega t + \phi\right) \left]\right.$
Interference fringes may be observed due to superposition of:

• A. $\left(i\right)$ and $\left(ii\right)$
• B. $\left(i\right)$ and $\left(iii\right)$
• C. $\left(ii\right)$ and $\left(iv\right)$
• D. $\left(iii\right)$ and $\left(iv\right)$

Answer 1

Answer: (D)

These waves are of same frequencies and they are coherent