Question

Two waves of equal amplitudes and wavelengths but differing in phase are superimposed. Amplitude of resultant wave is maximum when phase difference is

• A. Zero
• B. $\frac{\pi }{3}$
• C. $\pi$
• D. $\frac{\pi }{2}$

Answer 1

The correct option is A Zero

Resultant amplitude is given by,

$A_R=\sqrt{A_1^2+A_2^2+2A_1{A}_2\cos \varphi }$

For resultant amplitude to be maximum, $\cos \varphi =1$

$\Rightarrow \varphi =0$

Hence, option $\left(\text{A}\right)$ is correct.