Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass ? The speed of light vacuum is \( 3 \) x \( 10^8 ms^{-1} \).

Refractive index of glass, \( n_g \)= 1.50.
speed of light in vacuum:

\(\Rightarrow \) c=\( 3 \) x \( 10^8 ms^{-1} \)

\(\therefore \) Speed of light in glass = \( \frac{c}{n_g} \) = \( \frac{ 3 ×10^8}{1.5} \)

=2 x \( 10^8 ms^{-1} \)