A rectangular glass block `(mu = 1.5)` is on top of a sheet of paper on which there on which
Channel: Doubtnut
Date: 20/02/2020

A rectangular glass block `(mu = 1.5)` is on top of a sheet of paper on which there on which there is a small dot. There is a layer of liquid between the paper and the glass block. The dot is visible through a vertical face up to a point where the angle of emergence of light (starting from the dot) is `30�`. Find the refractive index `(m_(0))` of the liquid. Can we see the dot through a vertical face if the liquid layer is replaced with air? `sin^(-1).(2)/(3) = 42^(@)`