Question

A light ray l is incident on a plane mirror M. The mi is rotated in the direction as shown in the figure b arrow at frequency 9/π rps. The light reflected by the mirror is received on the wall W at a distance 10 m from the axis of rotation. When the angle of incidence becomes 37° the speed of the spot (a point) on the wall is:

Answer 1

Rotational speed of reflected light is given by,ω'=2×92×2π=18π rad/sNow, v'=Rω'The velocity of spot on wall is given as,v cos (900−370)=Rω'v cos 530=Rω'v=10cos 530×36cos 530=36×259=1000 rad/s
 

Answer 2

Answer: 500m/s

Explanation: