Question

Light is incident from air on oil at an angle of ${30}^{\circ }$. After moving through oil-1 and another medium; oil-2, it enters glass and then it enters water. If the refractive indices of glass and water are 1.5 and 1.3, respectively, find the angle which the ray makes with normal in water.

• A. $si{n}^{-1}\left(\frac{1}{2.4}\right)$
• B. $si{n}^{-1}\left(\frac{1}{2.5}\right)$
• C. $si{n}^{-1}\left(\frac{1}{2.6}\right)$
• D. $si{n}^{-1}\left(\frac{1}{2.8}\right)$

Answer 1

The correct option is C $si{n}^{-1}\left(\frac{1}{2.6}\right)$

As we know
$\mu .sin\left(i\right)=\left(constant\right)\Rightarrow \mu .sin(i{)}_{air}={\mu }_{water}sin(r{)}_{water}sin\left({30}^{\circ }\right)=1.3\times sin\left(r\right)sin\left(r\right)=\frac{1}{2\times 1.3}=\frac{1}{2.6};r=si{n}^{-1}\left(\frac{1}{2.6}\right)$