Two points are located at a distance of 10 m and 15 m from the source of oscillation. The period of oscillation is 0.05 sec and the velocity of the wave is 300 m / sec . What is the phase difference between the oscillation of two points ?

Question

$\begin {array} {1 1} (1)\;\large\frac{\pi}{6} & \quad (2)\;\large\frac{\pi}{3} \\ (3)\;2\large\frac{\pi}{3} & \quad (4)\;\pi \end {array}$