Question

A liquid of refractive index 1.5 is poured into a cyclindrical jar of radius 20 cm upto a height of 20 cm. A small bulb at the centre of bottom glowing. Find area of the liquid surface through which the light of the bulb passes into air.

Answer 1

From `r = (h)/(sqrt(mu^(2) -1))`
Area of the surface through which the light passes
`A = pi r^(2) = (pi xx (0.20)^(2))/((1.5)^(2) -1 ) = 0.1005 m^(2)`