Question

By properly combining two prisms made of different materials, it is possible to
(a) have dispersion without average deviation
(b) have deviation without dispersion
(c) have both dispersion and average deviation
(d) have neither dispersion nor average deviation

Answer 1

Answer:

Option C is the correct answer

Answer 2

By properly combining two prisms made of different materials, it is possible to have dispersion without average deviation,  have deviation without dispersion, have both dispersion and average deviation.

Explanation:

This way, we can merge two prisms,

(i) Deviation is zero but not dispersion.

(ii) Dispersion is zero but there is no difference. But in any case both variance and dispersion at the same time can not be zero  

We can either have deviation or not and the same for dispersion as only μ is different and prism angle is right in our choice option A, B, C.  

Thus, option (a), (b) and (c) is the correct option.