A light ray passes from crown glass into an unknown solid material
PHYSICS · Subjective · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A light ray passes from crown glass (n=1.52) into an unknown solid material. The refracted ray is observed to make an angle of 25∘ with the normal while the incident angle in glass is 40∘.
(a) Calculate the refractive index of the unknown solid.
(b) Determine the critical angle for light travelling from the solid back into crown glass.
(c) The solid is now immersed in water (n=1.33) and the same ray inside the solid strikes the solid–water boundary at an angle of 35∘ with the normal. State, with calculation, whether total internal reflection will occur at this boundary.
(d) Explain how parts (b) and (c) together illustrate the dependence of the critical angle on the surrounding medium.