Two identical harmonic pulses travelling in opposite directions in a taut string approach each other. At the instant when they completely overlap,the total energy of the string will be

The similarity between sound and light waves is:

$A$ narrow tube is bent in the form of a circle of radius $R,$ as shown in the figure. Two small holes $S$ and $D$ are made in the tube at positions right-angled to each other. $A$ source placed at $S$ generates a wave of intensity $I_0$ which is equally divided into two parts: one part travels along the longer path,while the other travels along the shorter path. Both the waves meet at point $D$ where a detector is placed. The maximum value of $\lambda$ to produce a minima at $D$ is given by

Two waves $Y_1 = A_1 \sin(\omega t - \beta_1)$ and $Y_2 = A_2 \sin(\omega t - \beta_2)$ superimpose to form a resultant wave whose amplitude is

Two sound waves each of wavelength $\lambda$ and same amplitude $A$ interfere at point $Q$. If the path difference is $\frac{\lambda}{4}$, the amplitude of the resultant wave at point $Q$ is $[\sin \frac{\pi}{2} = 1, \cos \frac{\pi}{2} = 0]$

Two waves originating from $S_1$ and $S_2$,having zero initial phase difference and common wavelength $\lambda$,will show completely destructive interference at $P$,if $(S_1 P - S_2 P)$ is