Question

A mark is made on the surface of a glass sphere of diameter $10cm$ 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. $15cm$
• B. $17.5cm$
• C. $20cm$
• D. $22.5cm$

Answer 1

The correct option is A $15cm$

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

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

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

$\frac{1}{\vartheta }=\frac{-1}{20cm}$

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