Question

A prism is an optical medium bounded by three refracting plane surfaces. A ray of light suffers successive refractions on passing through its two surfaces and deviates by a certain angle from its original path. The refractive index of the material of the prism is given by `mu = sin((A + deltam)/2)//sin  A/2`. If the angle of incidence on the second surface is greater than an angle called critical angle, the ray will not be refracted from the second surface and is totally internally reflected.

When a ray of light of wavelength λ and frequency v is refracted into a denser medium ______.

Options

• λ and v both increase.

• λ increases but v is unchanged.

• λ decreases but v is unchanged.

• λ and v both decrease.

Answer 1

When a ray of light of wavelength λ and frequency v is refracted into a denser medium λ decreases but v is unchanged.

Explanation:

When light is refracted into a denser material, the frequency remains constant while the wavelength drops.

We know, `mu = (v_(rarer))/(v_(denser)) > 1`

⇒ v_rarer > v_denser

⇒ λ₁v₁ > λ₁v₂   ...[as v₁ = v₂]

⇒ λ₁ > λ2