Question

Over the visible region, the refractive index of a glass is given by the formula n = c_1 + c_2/lambda^2, where c_1, c_2 are constants, with c_2 = 3 times 10^4 nm^2. White light passes through a thin prism of 5 degree apex angle made from this glass. Determine the difference in the deviation angle between the extreme red (700 nm), the green (550 nm), and the violet (400 nm) rays.

Answer 1

Angle of deviation of a prism is given as,

where n is the refractive index for a particular light.

Now, for red light,

similarly , for green and violet light,

so the deviation angle is,

So the difference between the angles,