Question

A transparent cube of $0.21\, m$ edge contains a small air bubble. Its apparent distance when viewed through one face of the cube is $0.10\, m$ and when viewed from the opposite face if $0.04\, m$. The actual distance of the bubble from the second face of the cube is

• A. 0.06 m
• B. 0.17 m
• C. 0.05 m
• D. 0.04 m

Answer 1

Answer: (A)

0.06 m

Answer 2

$\text{Refractive index =}\frac{\text{real depth}}{\text{apparent depth}}$
$\therefore \frac{x}{0.04}=\frac{0.21-x}{0.10}$
$\Rightarrow 0.21\times 0.04-x\times 0.04=0.10x$
$\Rightarrow x=\frac{0.21\times 0.04}{0.14}$
$=0.06\,m$