Question

Light entering an air glass (µ = 1.5) boundary is partly reflected and partly refracted. If the incident and reflected rays are at right angles to each other, the angle of refraction r is given by ____________.

Options

• sin r = `sqrt2/3`

• sin r = `sqrt((2/3)`

• sin r = `2/13`

• sin r = `2/sqrt3`

Answer 1

Light entering an air glass (µ = 1.5) boundary is partly reflected and partly refracted. If the incident and reflected rays are at right angles to each other, the angle of refraction r is given by

sin r = `sqrt2/3`.

Explanation:

i + i' = 90° where, i' is angle of reflection

⇒ i = 45° (∵ i = i')

µ = `sini/sinr = 3/2`

sin r = `2/3` × sin i

        = `2/3 × 1/sqrt2 = sqrt2/3`