Question

A prism is made of glass of unknown refractive index. A parallel beam of light incident on a face of the prism. By rotating the prism, the angle of minimum deviation is measured to be ${40}^o$. What is the refractive index of the material of the prism? If the prism is placed in water (refractive index 1.33), predict the new angle of minimum deviation of a parallel beam of light. The refracting angle of the prism is ${60}^o$.

Answer 1

(Given)



= = 1.532
Now, when the prism is held in water,





Therefore,