A point source of light is placed at a distance below the surface of a large

PHYSICS · Subjective · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments

Problem

A point source of light is placed at a distance

h

below the surface of a large, deep lake. Show that the fraction

f

of light that escapes directly from the water surface is independent of

h

and is given by

f=\frac{1-\sqrt{1-1/\mu^2}}{2}.