A transparent cube of `15 cm` edge contains a small air bubble. Its apparent depth when viewed through one face is `6 cm` and when viewed through the opposite face is `4 cm`. Then the refractive index of the material of the cube is

Options

A. `2.0`
B. `2.5`
C. `1.6`
D. `1.5`

Answer

D

Explanation

From left: apparent depth `=x/mu=4` …(i)
From right: apparent depth `=(15-x)/(mu)=6` …..(ii)
(i) + (ii)
`(x+15-x)/(mu)=4+6=10`
`mu=(15)/(10)=3/2=1.5`