Q: Two conducting spheres of radii r_{1} and r_{2} are at the same potential. The ratio of their charges is

(a) $\large \frac{r_1^2}{r_2^2} $

(b) $\large \frac{r_2^2}{r_1^2} $

(c) $\large \frac{r_1}{r_2} $

(d) $\large \frac{r_2}{r_1} $

Ans: (c)

Sol: $\large V_1 = V_2$

$\large \frac{1}{4 \pi \epsilon_0} \frac{q_1}{r_1} = \frac{1}{4 \pi \epsilon_0} \frac{q_2}{r_2} $

$\large \frac{q_1}{q_2} = \frac{r_1}{r_2} $