Q 12-09-117JEE MainJEE Main 2023 (11 Apr, Shift 1)Medium
The radius of curvature of each surface of a convex lens having refractive index $1.8$ is $20\ \text{cm}$. The lens is now immersed in a liquid of refractive index $1.5$. The ratio of power of lens in air to its power in the liquid will be $x:1$. The value of $x$ is ______.
Numerical value type. Enter your answer.
Answer: 4
$P\propto\left(\dfrac{\mu_l}{\mu_m}-1\right)$: in air $0.8$; in the liquid $\dfrac{1.8}{1.5}-1=0.2$. Ratio $=4:1$.
Solution by Sreeraj P, M.Sc Physics