Question

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

• A. 2.0
• B. 2.5
• C. 1.6
• D. 1.5

Answer 1

Answer: (D)

Let real depth of the bubble from one side is $x$. Then
$\mu =\frac{x}{6}=\frac{15-x}{4}$
$\therefore x=9cm$
Hence, $\mu =\frac{x}{6}=\frac{9}{6}$
$=1.5$