Question

The speed of light in air is 3 x 10⁸ m/s.The speed of light in glass of refractive index 1.5 is ?

a) 4.5 x 10⁸ m/s b) 0.2 x 10⁸ m/s c) 3 x 10⁸ m/s d) 2 x 10⁸ m/s e)3.5 x 10⁸ m/s

Answer 1

$$\begin{gathered} Refractiveindexofamedium=\frac{Speedoflightinair}{Speedoflightinanymedium} \\ Onsubstitutingthevalues \\ 1.5=\frac{3x{10}^8{\displaystyle \frac{m}{s}}}{speedoflightinglass} \\ Speedoflightinglass=\frac{3x{10}^8}{1.5}=2x{10}^{8}m/s \end{gathered}$$