Question

The diagram shows a spherical surface which separates two media of refractive indices, $\mu _{1}$ and $\mu _{2}$ , respectively. Now, a point object is placed on the principal axis as shown in the figure. Then

• A. Real image will form if $\mu _{1}>\mu _{2}$ and for all values of $u$
• B. Real image for some values of $u$ if $\mu _{1}>\mu _{2}$
• C. Virtual image will form if $\mu _{1}>\mu _{2}$
• D. Virtual image will form if $\mu _{1} < \mu _{2}$

Answer 1

Answer: (C)

$\frac{\mu _{2}}{v}-\frac{\mu _{1}}{- u}=\frac{\mu _{2} - \mu _{1}}{R}$
$\Rightarrow v=\frac{u R \mu_{2}}{u\left(\mu_{2}-\mu_{1}\right)-R \mu_{1}}$
$\Rightarrow v=\frac{u R \mu_{2}}{u \mu_{2}-\mu_{1}(u+R)}$
We can see that $\mu _{1}>\mu _{2}$ then image distance is negative which means virtual image