Q 12-01-065JEE MainJEE Main 2024 (31 Jan, Shift 1)Easy
Two charges $q$ and $3q$ are separated by a distance $r$ in air. At a distance $x$ from charge $q$, the resultant electric field is zero. The value of $x$ is:
Answer: (C) $\dfrac{r}{1 + \sqrt3}$
For like charges the null point lies between them:
$$\frac{kq}{x^2} = \frac{k(3q)}{(r - x)^2} \Rightarrow r - x = \sqrt3\,x \Rightarrow x = \frac{r}{1 + \sqrt3}$$
Solution by Sreeraj P, M.Sc Physics