Question

A mark on the surface of a glass sphere of diameter 10 cm and refractive index 1.5. It is viewed through the glass from a portion directly opposite. The distance of the image of the mark from the center of the sphere will be

• A. 15 cm
• B. 17. 5 cm
• C. 20 cm
• D. 22.5 cm

Answer 1

The correct option is A 15 cm

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

$\frac{1}{\vartheta }-\frac{1.5}{(-10)}=\frac{1-1.5}{5}$

$\frac{1}{v}=\frac{1}{10}-\frac{1.5}{10}$

$\frac{1}{\vartheta }=\frac{-0.5}{10}$

$\vartheta =-20cm$

$d=20cm-5cm=15cm$