Question

A point charge of $10\, \mu C$ is placed at the origin. At what location on the $X$-axis should a point charge of $40 \, \mu C$ be placed so that the net electric field is zero at $x=2 \, cm$ on the $X$-axis?

• A. $x=-4 \,cm$
• B. $x=4 \, cm$
• C. $x=8 \,cm$
• D. $x=6 \,cm$

Answer 1

Answer: (D)

$E_P=\frac{K \times 10}{2^2}-\frac{K \times 40}{\left(x_0-2\right)^2}=0$
$\frac{1}{2}=\frac{2}{x_0-2}$
$x_0-2=4$
$x_0=6\, cm$