Question

(i) Can the absolute refractive index of a medium be less than one?
(ii) A coin placed at the bottom of a beaker appears to be raised by $4.0cm$. If the refractive index of water is $4/3$, find the depth of the water in the beaker.

Answer 1

(i) The absolute refractive index of a medium cannot be less than one.

(ii) Given : Shift in the position of the coin $=4cm$

Refractive index ${(}_a{\mu }_m)=\frac{4}{3}$

Real depth $=$ ?

We know that : Shift in the position of the coin $=$ Real depth $(1-\frac{1}{{}_a{\mu }_m})$

$4=$ Real depth $(1-\frac{3}{4})$

$4=$ Real depth $\times \frac{1}{4}$

Real depth of water$=\frac{4\times 4}{1}$ $=16cm$