Question

In the arrangement shown, separation between observer and object as seen by observer is :-

• A. $60cm$
• B. more than $60cm$
• C. less than $60cm$
• D. depends upon $\mu$

Answer 1

The correct option is A $60cm$

$\begin{array}{c}\frac{{\mu }_1}{V}-\frac{{\mu }_2}{u}=\frac{{\mu }_1-{\mu }_2}{R}\\ \text{in}u=R\\ \frac{{\mu }_1}{V}-\frac{{\mu }_2}{-R}=\frac{{\mu }_1-{\mu }_2}{-R}\\ \frac{{\mu }_1}{V}=\frac{{\mu }_1}{R}\Rightarrow V=R\end{array}$

In the given case the object is

kept at Radius of curvature w.r.t all

refracting surfaces

the object and image will be at

Same place.

So Distance $=20+10+10+10+10$

$=60cm$

option $A$ is correct-