Question

Calculate the velocity of light in a glass block of refactive index $1.5$. Velocity of light in air = $3.0\times {10}^{8}m{s}^{-1}$

• A. $2\times {10}^{8}m/s$
• B. $2.3\times {10}^{8}m/s$
• C. $3.2\times {10}^{8}m/s$
• D. $6\times {10}^{8}m/s$

Answer 1

The correct option is A $2\times {10}^{8}m/s$

refractive index of glass $=\frac{\text{velocity of light in vacuum}}{\text{velocity of light in glass}}$

$1.5=\frac{3\times {10}^8}{v}$

$\Rightarrow v=2\times {10}^{8}m/s$