(a) What is meant by the term “critical angle” for a ray of light travelling from one…
PHYSICS · Subjective · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
(a) What is meant by the term “critical angle” for a ray of light travelling from one medium to another?
(b) A narrow beam of white light is incident from a crown-glass block (refractive index for red light 1.515 and for violet light 1.532) into water of refractive index 1.33. Which colour, red or violet, will have the larger critical angle at the glass–water boundary? Give a reason based on refractive indices.
(c) For the same crown glass, compare qualitatively the critical angles at its interface with air and with water. Explain your answer without performing any numerical calculation.