A string of mass $2.5\ kg$ is under a tension of $200\ N$ . The length of the stretched string is $20.0\ m$ . If the transverse jerk is struck at one end of the string, the disturbance will reach the other end in …. $\sec$

The displacement of an elastic wave is given by the function : $y = 3\, sin\,\omega t + 4\, cos\,\omega t$ where $y$ is in $cm$ and $t$ is in $s$. The resultant amplitude is …… $cm$

A small source of sound moves on a circle as shown in the figure and an observer is standing on $O.$ Let $n_1,\, n_2$ and $n_3$ be the frequencies heard when the source is at $A, B$ and $C$ respectively. Then

Three waves of equal frequency having amplitudes $10\,\mu m$, $4\,\mu m$, $7\,\mu m$ arrive at a given point with successive phase difference of $\pi /2$, the amplitude the resulting wave in $\mu m$ is given by