The Total solution for NCERT class 6-12
Light incident normally ona plane mirror attached to a galvanometer coil retraces backwards as shown inFig. 9.36. A current in the coil produces a deflection of 3.5° of the mirror.What is the displacement of the reflected spot of light on a screen placed 1.5m away?
Angle of deflection, θ =3.5°
Distance of the screen from themirror, D = 1.5 m
The reflected rays get deflected by anamount twice the angle of deflection i.e., 2θ= 7.0°
The displacement (d) of the reflectedspot of light on the screen is given as:
Hence,the displacement of the reflected spot of light is 18.4 cm.