Question

In a stationary wave represented by $Y =2 a \cos kx \sin \omega t$ the intensity at a certain point is maximum when

• A. $\cos kx$ is maximum
• B. $\cos kx$ is minimum
• C. $\sin\, \omega t$ is maximum
• D. $\sin\, \omega t$ is minimum

Answer 1

Answer: (A)

$\cos kx$ is maximum

Answer 2

Intensity $\propto(\text { Amplitude })^{2} \propto(2 a \cos k x)^{2}$ Hence, intensity will be maximum when $\cos k x$ is maximum.