Question

From a point source a light falls on a spherical glass surface $(\mu = 1.5$ and radius of curvature $= 10\, cm$). The distance between point source and glass surface is $50 \,cm$. The position of image is

• A. $25\,cm$
• B. $50\,cm$
• C. $100\,cm$
• D. $150\,cm$

Answer 1

Answer: (B)

Using, $\frac{\mu_{2}}{v}-\frac{\mu_{1}}{u}=\frac{ \mu_{2}-\mu_{1}}{R}$
Here, $\mu_{1}=1, \mu_{2} = 1.5, u = -50 \,cm $
$ \therefore \frac{1.5}{v} - \frac{1}{\left(-50\right)} $
$ = \frac{\left(1.5-1\right)}{10}$
$\Rightarrow \frac{1.5}{v} $
$= 0.05 - 0.02 = 0.03 $
$ \Rightarrow v = 50 \,cm$