Question

A glass sphere of radius $R=10cm$ is kept inside water. A point object $O$ is placed at $20cm$ from $A$ as shown in Fig. Find the position and nature of the image when seen from other side of the sphere. Given ${\mu }_g=\frac{3}{2}$ and ${\mu }_w=\frac{4}{3}$.

• A. $200cm$, virtual
• B. $100cm$, real
• C. $100cm$, virtual
• D. $300cm$, virtual

Answer 1

The correct option is C $100cm$, virtual

for first refracting surface

$u=-20$ ; $R=+10$

$\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{R}$

$\frac{3}{2v}-\frac{-4}{3\ast 20}=\frac{1}{60}$

$v=-30$ , no for the second refracting surface

$u=-50$ ; $R=-10$

$\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{R}$

$\frac{4}{3v}+\frac{3}{2\ast 50}=\frac{1}{60}$

$v=-100$, image is virtual

option $C$ is correct