JEE Main 20209 Jan, Evening shiftPhysicsMediumOptics190× since 2002
There is a small source of light at some depth
below the surface of water (refractive
index = ) in a tank of large cross sectional
surface area. Neglecting any reflection from the
bottom and absorption by water, percentage of
light that emerges out of surface is (nearly) :
[Use the fact that surface area of a spherical cap
of height h and radius of curvature r is 2rh]: