Question

In a medium of refractive index 1.6 and having a convex surface has a point object in it at a distance of 12 cm from the pole. The radius of curvature is 6 cm. Locate the image as seen from air

• A. A real image at 30 cm
• B. A virtual image at 30 cm
• C. A real image at 4.28 cm
• D. A virtual image at 4.28 cm

Answer 1

The correct option is B A virtual image at 30 cm

Using the relation $\frac{{\mu }_2}{\nu }-\frac{{\mu }_1}{\mu }=\frac{{\mu }_2-{\mu }_1}{R}$

where ${\mu }_1=1.6$, ${\mu }_2=1$ and $R=-6cm$

Let the image distance be $\nu$.

Object distance $u=-1.2cm$
$\frac{1}{\nu }-\frac{1.6}{-12}=\frac{1-1.6}{-6}$

$\frac{1}{\nu }+\frac{1.6}{12}=0.1$

$\nu =-30cm$

Since $\nu$ is $-ve$, so virtual image will be formed.