Q 12-09-106JEE MainJEE Main 2023 (31 Jan, Shift 2)Medium
A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index $\dfrac53$ is poured inside the bucket, then microscope has to be raised by $30\ \text{cm}$ to focus the object again. The height of the liquid in the bucket is
Answer: (A) $75\ \text{cm}$
The object appears raised by $h\left(1-\dfrac1\mu\right)=h\left(1-\dfrac35\right)=0.4h$.
$0.4h=30\ \text{cm}\Rightarrow h=75\ \text{cm}$.
Solution by Sreeraj P, M.Sc Physics