Question

The image formed by the converging beam after refraction through the curved surface is formed at

• A. $x=40 \, cm$
• B. $\text{x} = \frac{4 0}{3} \text{cm}$
• C. $\text{x} = - \frac{4 0}{3} \text{cm}$
• D. $\text{x} = \frac{1 8 0}{7} \text{cm}$

Answer 1

Answer: (A)

We know that;
$\frac{\text{μ}_{2}}{\text{v}} - \frac{\text{μ}_{1}}{\text{u}} = \frac{\text{μ}_{2} - \text{μ}_{1}}{\text{R}}$
$\frac{1}{\text{v}} - \frac{3}{2 \times 3 0} = \frac{1 - \frac{3}{2}}{+ 2 0}$
$\frac{1}{\text{v}} = - \frac{1}{4 0} + \frac{1}{2 0} = + \frac{1}{4 0}$
$v=40 \, cm$ .