Question

In the shown figure, a ray of light is
incident from air on one face of a
equilateral glass prism. When
angle of incidence is 90°, the
refracted ray from the first face
goes undeviated from the second
face. The refractive index of the
material of the prism is
AIR
600
AIR
60°
60°​

Answer 1

Explanation:

As shown in the figure, on normal incidence at first surface, the angle of incidence at second surface is 60°.

In the border case of total internal reflection just happening,

μsin60

∘

=1×sin90

∘

=> μ=2/

3

Also note that if μ is greater than this value then internal reflection always takes place.