MCQ
$A$ concave mirror is placed on a horizontal surface and two thin uniform layers of different transparent liquids (which do not mix or interact) are formed on the reflecting surface. The refractive indices of the upper and lower liquids are $\mu_1$ and $\mu_2$ respectively. The bright point source at a height $‘d’$ ($d$ is very large in comparison to the thickness of the film) above the mirror coincides with its own final image. The radius of curvature of the reflecting surface therefore is
- A$\frac{{{\mu _1}\,d}}{{{\mu _2}}}$
- B$\mu_1\mu_2d$
- C$\mu_1d$
- ✓$\mu_2d$
