Question

There is a small air bubble at the centre of a solid glass sphere of radius 'r' and refractive index ${}^{\prime }{\mu }^{\prime }$. What will be the apparent distance of the bubble from the centre of the sphere, when viewed from outside?

• A. r
• B. $\frac{r}{\mu }$
• C. $r\left(1-\frac{1}{\mu }\right)$
• D. Zero

Answer 1

The correct option is D Zero

$\begin{array}{c}\frac{{\mu }_1}{u}-\frac{{\mu }_2}{v}=\frac{{\mu }_1-{\mu }_2}{R}\\ \text{Here}\\ \frac{1}{k}-\frac{{\mu }_1}{v}=\frac{1-{\mu }_1}{R}\\ -\frac{{\mu }_1}{v}=-\frac{{\mu }_1}{k}\\ v=R\\ \text{so the bubble will be at center when}\\ \text{viewed from air.}\\ \text{so apparent distance}=R-R\\ 0\\ \text{So (D) zero is the right option}\end{array}$