Question

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

• A. 30 cm left
• B. infinity
• C. 1 cm to the right
• D. 18 cm to the left

Answer 1

Answer: (A)

30 cm left

Answer 2

$\begin{array}{l} \mu_{1}(\text { air })=1 \\\ \mu_{2} \text { (glass) }=1.5 \\\ u =-15 cm \\\ R =30 cm \\\ \frac{\mu_{2}-\mu_{1}}{1.5-1}=\frac{\mu_{2}}{ v }-\frac{\mu_{1}}{4} \\\ \frac{1.5}{30}-\frac{1}{15} \\\ v =-30 \end{array}$
Ans. $30 cm$ towards the left.