Q. The optical path 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
Explanation
(b) Optical path $\mu x = \ $constant
$i.e.,\ \mu_{1}x_{1} = \mu_{2}x_{2}$
$\Rightarrow 1.53 \times 4 = \ \mu_{2} \times 4.5$
$\Rightarrow \mu_{w} = \frac{1.53 \times 4}{4.5} = \ 1.36$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.