Question

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. $t(1-\frac{1}{\mu })$ away
• B. $t(1+\frac{1}{\mu })$ away
• C. $t(1-\frac{1}{\mu })$ nearer
• D. $t(1+\frac{1}{\mu })$ nearer

Answer 1

Answer: (A)

$t(1-\frac{1}{\mu })$ away

Shift $\Delta x=\left(1-\frac{1}{\mu }\right)t$

shifted in the direction of ray.