Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Two waves of equal amplitude and frequency interfere each other. The ratio of intensity when the two waves arrive in phase to that when they arrive $90^{\circ}$ out of phase is

Wave Optics

Solution:

Resultant intensity $I=4 I_{0} \cos ^{2}(\phi / 2)$
$\Rightarrow \frac{I_{1}}{I_{2}}=\frac{\cos ^{2}\left(\phi_{1} / 2\right)}{\cos ^{2}\left(\phi_{2} / 2\right)}$
$=\frac{\cos ^{2} 0}{\cos ^{2}(90 / 2)}=\frac{2}{1}$