A ray of light incident at an angle of incidence i₁ passes through an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges at an angle of emergence i₂.

(i) How is the angle of emergence 'i₂' related to the angle of incidence 'i₁'.

(ii) What can you say about the angle of deviation in such a situation?

A light ray of yellow colour is incident on an equilateral glass prism at an angle of incidence equal to 48° and suffers minimum deviation by an angle of 36°.

(i) What will be the angle of emergence?

(ii) If the angle of incidence is changed to (a) 30°, (b) 60°, state in each case whether the angle of deviation will be equal to less than or more than 36°?

How does the deviation produced by a prism depend on

(i) the refractive index of its material, and

(ii) the wavelength of incident light

Define the term angle of deviation.