Question

light incident normally on a plane mirror attach a galvanometer retraces backward deflection 15° in the mirror what is the displacement of reflected spot of light in the screen placed 1.5 m away
​

Answer 1

Explanation:

θ=3.5

o

,D=1.5m

Reflected rays get deflected by an amount twice the angle of deflection, i.e., 2θ=7

o

d is the displacement of reflected spot of light on screen.

tan2θ=d/1.5⇒d=18.4cm