Question

Light passes from air into a liquid. The angle of incidence is 60${}^{\circ }$. The deviation produced is 15${}^{\circ }$. The refractive index of liquid is:

• A. $1.5$
• B. $1.33$
• C. $1.22$
• D. $1.63$

Answer 1

The correct option is C $1.22$

Since light passes from rarer to denser medium,

So, $i>r$

So, $r=i-\delta$

$={60}^{\circ }-{15}^{\circ }$

$={45}^{\circ }$

Using ${\mu }_{1}sini={\mu }_{2}sinr$

$1\times sin{60}^{\circ }={\mu }_{2}sin{45}^{\circ }$

$\frac{\sqrt{3}}{2}={\mu }_2\times \frac{1}{\sqrt{2}}$

${\mu }_2=\frac{\sqrt{3}}{\sqrt{2}}$

$=1.22$