Question

Calculate the refractive index of the material of a glass slab. Given that the speed of light through the glass slab is $2\times {10}^8\mathrm{m}/\mathrm{s}$ and in air is $3\times {10}^8\mathrm{m}/\mathrm{s}$.

Answer 1

Step 1: Given

Speed of light through the glass slab $=2\times {10}^8\mathrm{m}/\mathrm{s}$

Speed of light in the air $=3\times {10}^8\mathrm{m}/\mathrm{s}$

Step 2: Formula used

Refractive index of the medium, $\mathrm{\mu }=\frac{\mathrm{Speed}\mathrm{in}\mathrm{air}}{\mathrm{Speed}\mathrm{in}\mathrm{medium}}$

Step 3: Calculating the refractive index of the medium

By using the refractive index formula,

$\mathrm{\mu }=\frac{\mathrm{Speed}\mathrm{in}\mathrm{air}}{\mathrm{Speed}\mathrm{in}\mathrm{medium}}$

$\mathrm{\mu }=\frac{3\times {10}^8}{2\times {10}^8}$

$\mathrm{\mu }=1.5$

Therefore, the refractive index of the medium is $1.5$.