Question

The optical path of a monochromatic light is same if it goes through $4.0\, cm$ of glass of $4.5\, cm$ of water. If the refractive index of glass is $1.53$, the refractive index of the water is

• A. 1.30
• B. 1.36
• C. 1.42
• D. 1.46

Answer 1

Answer: (B)

Optical path, $\mu x =$ constant
ie, $\mu_{1} \,x _{1}=\mu_{2} \,x _{2}$
$ \Rightarrow 1.53 \times 4=\mu_{2} \times 4.5$
$\Rightarrow \mu_{2}=\frac{1.53 \times 4}{4.5}=1.36$