Chapter 17, Problem 73A

To determine

To explain:Whether a spherical mirror or parabolic mirror is good for high quality telescope.

Explanation of Solution

Introduction:

Spherical aberration is a kind of aberration observed in an optical system which uses spherical mirrors. The light rays that are incident on the outer edge of the spherical mirror are reflected or refracted more or less compared to that incident close to the central portion of the spherical mirror. Due to this deviation in reflected or refracted light rays, the image produced by an optical system which uses a spherical mirror is of less quality. That is, the image produced is slightly blurry.

In the case of spherical mirror there will be an effect called spherical aberration which reduces the quality of the image formed. In the case of parabolic mirror there is no spherical aberration is observed. Hence, all the light rays reflected from the parabolic mirrors focus at the same point and hence the image formed is of best quality. Therefore, in order to produce a best quality image parabolic mirror is more suitable for a telescope.