Q. A beam of light is converging towards a point $I$ on a screen. A plane glass plate whose thickness in the direction of the beam $= t,$ refractive index $= \mu$, is introduced in the path of the beam. The convergence point is shifted by
A) $t\left( 1 - \frac{1}{\mu} \right)$ away
B) $t\left( 1 + \frac{1}{\mu} \right)$ away
C) $t\left( 1 - \frac{1}{\mu} \right)$ nearer
D) $t\left( 1 + \frac{1}{\mu} \right)$ nearer
Explanation
(a) Normal shift $\mathrm{\Delta}x = \left( 1 - \frac{1}{\mu} \right)t$ and shift takes place in direction of ray
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.