Question

Answer the following question in detail.

Explain and define the dispersive power of transparent material. Obtain its expressions in terms of angles of deviation and refractive indices.

Answer 1

1. The ability of an optical material to disperse constituent colours is its dispersive power.
2. It is measured for any two colours as the ratio of angular dispersion to the mean deviation for those two colours. Thus, for the extreme colours of white light, dispersive power is given by,
   `ω = (δ_"V"-δ_"R")/(((δ_"V"+δ_"R")/2))≈(δ_"V"-δ_"R")/(δ_"Y")=("A"("n"_"V"-"n"_"R"))/("A"("n"_"Y"-1))=("n"_"V"-"n"_"R")/("n"_"Y"-1)`