Question

A triangular glass prism has a refractive angle of 60 degree. if the minimum deviation by a ray of light passing through the glass is 42 degree. The refractive index of 

Answer 1

$$n=\frac{\sin\frac{A+\delta_m}{2}}{\sin\frac{A}{2}}\\ n=\frac{\sin\frac{60+42}{2}}{\sin\frac{60}{2}}\\ n=\frac{\sin 51}{\sin 30}=1.55$$