A bulb is placed at the centre of a circular track of radius \(10 \mathrm{~m}\). A vertical wall is erected touching the track at a point P. A man is running along the track with a speed of \(10 \mathrm{~m} / \mathrm{sec}\). Starting from P the speed with which his shadow is running along the wall when he is at an angular distance of \(60^{\circ}\) from \(\mathrm{P}\) is
(A) \(30 \mathrm{~m} / \mathrm{sec}\)
(B) \(40 \mathrm{~m} / \mathrm{sec}\)
(C) \(60 \mathrm{~m} / \mathrm{sec}\)
(D) \(80 \mathrm{~m} / \mathrm{sec}\)
Ans: (B)
