Question

For a material, the refractive indices for red, violet and yellow colour light are respectively 1.52, 1.64 and 1.60. The dispersive power of the material is [MP PMT 1991]
A) 2 B) 0.45 C) 0.2 D) 0.045

Answer 1

Ans is option C) 0.2
That is 1.64-1.52/0.60=0.2

Answer 2

Answer:

The dispersive power of the material is 0.2.

(C) is correct.

Explanation:

Given that,

Refractive indices for,

Red = 1.52

Violet = 1.64

Yellow = 1.60

The ratio of the angular dispersion and mean deviation is called dispersive power.

Dispersive power is independent of angle of prism but it is depend of material of prism.

Formula of the dispersive power is given as:

$\omega=\dfrac{(\mu_{v}-\mu_{r})A}{\mu_{y}-1}$

$\omega=\dfrac{1.64-1.52}{1.60-1}$

$\omega=0.2$

Hence, The dispersive power of the material is 0.2.