Question

In an experiment for determination of refractive index of glass of a prism by i - $\delta$ plot, it was found that a ray incident at angle ${35}^{\circ }$, suffers a deviation of ${40}^{\circ }$ and that it emerges at angle ${79}^{\circ }$. In that case which of the following is closest to the maximum possible value of the refractive index?

• A. 1.6
• B. 1.7
• C. 1.8
• D. 1.5

Answer 1

The correct option is D

1.5

From the given data $A=i+e-\delta ={74}^{\circ },\delta ={40}^{\circ }$

$Now,\mu =\frac{sin\left(\frac{A+{\delta }_m}{2}\right)}{sin\left(\frac{A}{2}\right)}<\frac{sin\left(\frac{A+\delta }{2}\right)}{sin\left(\frac{A}{2}\right)}\Rightarrow \mu <\frac{sin{57}^{\circ }}{sin{37}^{\circ }}\Rightarrow \mu <{1.39}^{\circ }$

Nearest value is 1.5