The angle of incidence of a ray of the light is 45°. If a ray of light travels from air to glass, find the angle of refraction. Refractive index of glass, µ_g = 1.5.

$$\begin{gathered} \text{ Given, }\angle i=45°=\text{ angle of incidence } \\ \text{ Refractive index of glass }={\mu }_g=1.5 \\ \text{ Angle of refraction, }r=\text{ ? } \\ \mu =\frac{\sin \angle i}{\sin \angle r}\text{ (from Snell's law) } \\ 1.5=\frac{\sin 45°}{\sin r} \\ 1.5=\frac{\left(\frac{1}{\sqrt{2}}\right)}{\sin r} \\ \sin r=\frac{1}{1.5\times \sqrt{2}} \\ \sin r=0.4728 \\ \text{ we get }\angle r\approx 28°\text{. } \end{gathered}$$