A ray of light is incident normally on a glass slab to thickness 5 cm and refractive index 1.6. The time taken to travel by a ray from source of light to surface of slab is same as to travel through g

Question

A ray of light is incident normally on a glass slab to thickness 5 cm and refractive index 1.6. The time taken to travel by a ray from source of light to surface of slab is same as to travel through glass slab. The distance of source from the surface is

TestHub · Accepted Answer

Let the distance of the source from the surface be $x$ .

The speed of light in air is $c$ and in the glass slab is $v = \frac{c}{μ}$ .

Time taken by light to travel from the source to the surface is $t_{1} = \frac{x}{c}$ .

Time taken by light to travel through the glass slab is $t_{2} = \frac{d}{v} = \frac{μ d}{c}$ .

Given that $t_{1} = t_{2}$ , we have:

$\frac{x}{c} = \frac{μ d}{c}$

$x = μ d$

Substituting the given values, $μ = 1.6$ and $d = 5$ cm:

$x = 1.6 \times 5 = 8$ cm.

Answer: 8 cm

Physics - Geometrical Optics Question with Solution | TestHub

Options:

Doubts & Discussion