Question

The absolute refractive index of the diamond is 2.1. What is the velocity of light in a diamond?

• A. $2.672\times {10}^{8}m/s$
• B. $1.428\times {10}^{8}m/s$
• C. $1.672\times {10}^{8}m/s$
• D. $2.428\times {10}^{8}m/s$

Answer 1

The correct option is B $1.428\times {10}^{8}m/s$

Velocity of light in vacuum, $c=3\times {10}^{8}m/s$
Let the velocity of light diamond be $v_d$
Absolute refractive index of diamond is given by:
${\mu }_d=\frac{c}{v_d}$
$v_d=\frac{c}{{\mu }_d}$
$v_d=\frac{3\times {10}^{8}m/s}{2.1}$
$v_d=1.428\times {10}^{8}m/s$