Question

In a prism, the refractive indices of different colours are
${\mu }_V=$ 1.6;
${\mu }_R=$ 1.52;
${\mu }_Y=$ 1.56.
The dispersive power of the prism is :

• A. $\frac{1}{56}$
• B. $\frac{1}{8}$
• C. $\frac{1}{7}$
• D. Infinite

Answer 1

The correct option is C $\frac{1}{7}$

Dispersive power of prism= $w=\frac{{\mu }_V-{\mu }_R}{{\mu }_Y-1}$

$w=\frac{1.6-1.52}{1.56-1}$

$w=\frac{1}{7}$