If two waves of same frequency and same amplitude, on superimposition produced a resultant disturbance of…

If two waves of same frequency and same amplitude, on superimposition produced a resultant disturbance of the same amplitude, the waves differ in phase by
  1. $\pi$
  2. $\frac{2\pi}{3}$
  3. $\frac{\pi}{2}$
  4. zero

Solution

Given, resultant disturbance, $a^2 = a^2 + a^2 + 2a^2 \cos \theta$ $\Rightarrow \quad \cos \theta = -\frac{1}{2} \Rightarrow \theta = \frac{2\pi}{3}$

Practice more Waves and Sound questions on Aicharya