Optics Question 637

Question: Focal length of a converging lens in air is R. If it is dipped in water of refractive index 1.33, then its focal length will be around (Refractive index of lens material is 1.5)

[RPMT 1997; EAMCET (Med.) 1995]

Options:

A) R

B) 2R

C) 4R

D) R / 2

Show Answer

Answer:

Correct Answer: C

Solution:

$ \frac{f _{l}}{f _{a}}=\frac{ _{a}{\mu _{g}}-1}{ _{l}{\mu _{g}}-1} $

Therefore $ f _{l}=4R $



NCERT Chapter Video Solution

Dual Pane