Looking for classes? Ksquare Career Institute, Bengaluru →
When a biconvex lens of glass having refractive index 1.47 is dipped in a liquid, it acts as a plane sheet of glass. This implies that the liquid must have refractive index
A
less than that of glass
B
equal to that of glass
C
less than one
D
greater than that of glass
Detailed Solution
$\frac{1}{f} = \left(\frac{\mu_2}{\mu_1} - 1\right)\left(\frac{1}{R_1} - \frac{1}{R_2}\right)$, where $\mu_2$ is for glass and $\mu_1$ for the liquid
A plane sheet has $f = \infty$, i.e. $\frac{1}{f} = 0$
$\frac{\mu_2}{\mu_1} - 1 = 0 \Rightarrow \mu_1 = \mu_2 = 1.47$
So the liquid has refractive index equal to that of glass.
A plane sheet has $f = \infty$, i.e. $\frac{1}{f} = 0$
$\frac{\mu_2}{\mu_1} - 1 = 0 \Rightarrow \mu_1 = \mu_2 = 1.47$
So the liquid has refractive index equal to that of glass.