Question

Refractive index of glass is $\frac{3}{2}$ then the speed of light in glass is

• A. $3\times {10}^{9}m/s$
• B. $2\times {10}^{9}m/s$
• C. $3\times {10}^{8}m/s$
• D. $2\times {10}^{8}m/s$

Answer 1

Answer: (D)

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

Refractive index of glass = $\frac{3}{2}$

Speed of light can be obtained by the formula

$\mu =\frac{c}{v}$

Substituting the values,

$\Rightarrow v=\frac{c}{\mu }=\frac{3\times {10}^8}{\frac{3}{2}}=2\times {10}^8\text{m/sec}$

The speed of light in glass will be $2\times {10}^8\text{m/sec}$.