Question

There are three prisms A, B, C of base width 5 cm each with an angle of prism 30°, 36°, 45° respectively. If the light of wavelength 5000A is incident on each of them, which has the highest resolving power?

(a) A

(b) B

(c) C

(d) All of them have the same resolving power

This question was posed to me in an international level competition.

My question is taken from Resolving Power topic in division Optics of Engineering Physics II

Answer 1

Right answer is (d) All of them have the same resolving power

For explanation I would say: The resolving power of a prism is directly proportional to the width of the base of the prism and inversely proportional to the cube of the wavelength of light. It is independent of the angle of prism. Thus, as the base width and the wavelength of light are the same in each case, all of them will have the same resolving power.