Q 12-01-077JEE MainJEE Main 2023 (25 Jan, Shift 2)Easy
A point charge of $10\ \mu\text{C}$ is placed at the origin. At what location on the $X$-axis should a point charge of $40\ \mu\text{C}$ be placed so that the net electric field is zero at $x=2\ \text{cm}$ on the $X$-axis?
Answer: (A) $x=6\ \text{cm}$
The $40\ \mu\text{C}$ charge must be on the far side of $x=2\ \text{cm}$ at distance $d$ with
$$\frac{k(10)}{2^2}=\frac{k(40)}{d^2}\ \Rightarrow\ d=4\ \text{cm}$$
So it is at $x=2+4=6\ \text{cm}$.
Solution by Sreeraj P, M.Sc Physics