Question

A glowing bulb is placed at a depth of $d$ in a transparent medium having refractive index $\mu$. An opaque disc is placed over the surface so that the bulb is not visible from the surface then.

• A. $\frac{r}{d}=\frac{1}{\mu }$
• B. $\frac{r}{\mu }=\frac{1}{d}$
• C. $\frac{r}{d}=\sqrt{\frac{1}{{\mu }^2-1}}$
• D. $\frac{r}{d}=\sqrt{\frac{\mu }{{\mu }^2-1}}$

Answer 1

The correct option is C $\frac{r}{d}=\sqrt{\frac{1}{{\mu }^2-1}}$

Option C is correct