Question

One side of a glass slab is silvered as shown in the figure. A ray of light is incident on the other side at angle of incidence ${45}^{\circ }$. Refractive index of glass is given as $\sqrt{2}$. The deflection suffered by the ray when it comes out of the slab is

• A. ${90}^{\circ }$
• B. ${180}^{\circ }$
• C. ${120}^{\circ }$
• D. ${45}^{\circ }$

Answer 1

The correct option is A ${90}^{\circ }$

According to Snell's law

$\frac{\sin {45}^{\circ }}{\sin r}=\sqrt{2}\Rightarrow \sin r=\frac{1}{2}\Rightarrow r={30}^{\circ }$

Hence total deflection $={45}^{\circ }-(-{45}^{\circ })={90}^{\circ }$
Hence correct option is (a).