What is the effect on the focal length of a convex lens when it is immersed in a liquid whose refractive index is equal to refractive index of the lens?
Answer & explanation
Correct answer: option 1
$\frac{1}{f} = (\frac{\mu_2}{\mu_1} - 1)(\frac{1}{R_2} - \frac{1}{R_1})$
Here $\mu_2 =\mu_1$
$\Rightarrow \frac{1}{f} = 0$
$f \rightarrow \infty$
A convex lens is dipped in a liquid whose refractive index is equal to the refractive index of the lens. Then its focal length will. become infinite.