Question

A ray of light travels from air to glass as shown. Give that the refractive index of air is $1.0$ and the refractive index of glass is $1.5$, what is the angle of refraction?

• A. ${22.6}^o$
• B. ${30.8}^o$
• C. ${35.3}^o$
• D. ${40.0}^o$

Answer 1

The correct option is C ${35.3}^o$

Refractive index of air $\left({\mu }_{air}\right)$= 1

Refractive index of glass $\left({\mu }_{glass}\right)$= 1

Angle of incidence (i) = ${60}^{\circ }$

From Snell’s law

${\mu }_{air}\sin i={\mu }_{water}\sin r$

$1\times \sin \left({60}^{\circ }\right)=1.5\times \sin r$

$\frac{\sqrt{3}}{2}\times \frac{2}{3}=\sin r$

$\sin r=\sqrt{3}$

$r={\sin }^{-1}\left(\sqrt{3}\right)$

$r={35.3}^{\circ }$

The angle of refraction is ${35.3}^{\circ }$