Question

A point object $O$ is placed in front of a glass rod having a spherical end of the radius of curvature $30cm$ . The image would be formed at

• A. 30 cm left from the pole
• B. Infinity
• C. 1 cm to the right from the pole
• D. 18 cm to the left from the object

Answer 1

Answer: (A)

By using lens maker's formula,
$\frac{\mu ₂}{v}-\frac{\mu ₁}{u}=\frac{\mu ₂-\mu ₁}{R}$
$⟹\frac{1.5}{v}-\frac{1}{\left(-15\right)}=\frac{1.5-1}{+30}$
$⟹v=-30cm$