By properly combining two prisms made of different materials, it is possible to (choose the incorrect option)

Options

A. dispersion without average deviation
B. deviation without dispersion
C. both dispersion and average deviation
D. neither dispersion nor average deviation

Answer

D

Explanation

We can combine twoprismsin such a way
(i) deviation is zero but dispersion not
(ii) dispersion is zerobut deviation is not. But in any situation both deviation & dispersion can not be zero simultaneously.