Question

For a glass prism of refractive index $\sqrt{3}$, the angle of minimum deviation is equal to the angle of the prism. The angle of the prism is nearly

• A. $80^{\circ }$
• B. $70^{\circ }$
• C. $60^{\circ }$
• D. $50^{\circ }$

Answer 1

Answer: (C)

$\mu =\frac{\sin \left(\frac{A+D}{2}\right)}{\sin \frac{A}{2}}$
gives $2\cos (A/2)=\mu$
or $\cos (A/2)=1.732/2=\sqrt{3}/2$
or $A=60^{\circ }$