Q 12-02-013NEETNEET 2021Top questionEasy
Two charged spherical conductors of radius $R_1$ and $R_2$ are connected by a wire. Then the ratio of surface charge densities of the spheres ($\sigma_1/\sigma_2$) is :
Answer: (C) $\dfrac{R_2}{R_1}$
Concept. Connected conductors share a potential: $q \propto R$; $\sigma = \dfrac{q}{4\pi R^2}$.
Step 1. Ratio. $\dfrac{\sigma_1}{\sigma_2} = \dfrac{R_1}{R_2} \cdot \dfrac{R_2^2}{R_1^2} = \dfrac{R_2}{R_1}$.
Answer. $\dfrac{R_2}{R_1}$ (Option C).
Solution by Sreeraj P, M.Sc Physics