In the visible region the dispersive powers and the mean angular deviations for crown and flint glass prisms are `omega, omega^(‘)` and d, `d^(‘)` respectively. The condition of getting dispersion with zero deviation, when the two prisms are combined is

Options

A. `sqrt(omega d)+sqrt(omega^(‘) d^(‘))=0`
B. `omega^(‘) d + omega d^(‘)=0`
C. `omega d + omega^(‘) d^(‘)=0`
D. `omega d + omega^(‘) d^(‘)=0`

Answer

C

Explanation

The condition for getting dispersion without deviation, when two prisms are combined is,
`omega d + omega^(‘) d^(‘) = 0`