A light ray `I` is incident on a plane mirror `M`.The mirror is rotated in the direction as shown in the figure by an arrow at frequency `(9)/(pi) "rev"//"sec"`,The light reflected by the mirror is received on the wall `W` at a distance `10m`from the axis of rotation .When the angle of incidence becomes `37^(@)`find the speed of the spot (a point) on the wall?
A. 10 m/s
B. 1000 m/s
C. 500 m/s
D. 20 m/s