Question

A ray of light strikes the glass slab at an angle 40° with the surface of the slab. Then the angle of incidence will be _______°.

Options

• 50

• 40

• 60

• 90

Answer 1

A ray of light strikes the glass slab at an angle 40° with the surface of the slab. Then the angle of incidence will be 50°.

Explanation:

The angle of incidence is defined as the angle between the normal drawn at the point of incidence and the incident light ray. Here the light ray is falling at the point of incidence at an angle of 40°. Thus:

Glancing angle is given as 40°

Hence angle of incidence ∠i = 90° - 40°

∠i = 50°