Two identical sinusoidal waves each of amplitude $10 \,mm$, with a phase difference of $90^{\circ}$ are travelling in the same direction in a string. The amplitude of the resultant wave is

The similarity between sound and light waves is:

Two pulses in a stretched string whose centres are initially $8 \ cm$ apart are moving towards each other as shown in the figure. The speed of each pulse is $2 \ cm/s$. After $2 \ seconds$,the total energy of the pulses will be

When two sound waves having amplitude $3$ and $5$ units are superimposed,then the ratio of maximum to minimum intensity of the wave produced is:

Two waves have equations $x_1 = a \sin(\omega t + \phi_1)$ and $x_2 = a \sin(\omega t + \phi_2)$. If the frequency and amplitude of the resultant wave remain equal to those of the superimposing waves,then the phase difference between them is:

Four independent waves are represented by the following equations. Which of these equations represent the phenomenon of interference?
$Y_1 = a_1 \sin \omega t$
$Y_2 = a_2 \sin \omega t$
$Y_3 = a_3 \cos \omega t$
$Y_4 = a_4 \sin (\omega t + \frac{\pi}{3})$