Question

A charge of $+2\mu C$ is placed at $x=0$ and a charge of $32\mu C$ at $x=60cm$. A third charge $Q$ is placed on the $x$-axis, such that it experiences no force. The distance of the point from $+2\mu C$ is (in $cm$ )

• A. 12
• B. 20
• C. 15
• D. 10

Answer 1

Answer: (A)

The coulombic ferce is ginen by:- $F=\frac{q_1{q}_2}{4\pi {\text{ tor }}^2}$ $r\to$ Dixtance of separati en
$q_1,q_2\to$ Magnitude of the two charges
to $\to$ Permittivity of free spare.
Let charge $Q$ be placed at a distavce ' $x$ ' from $2\mu C$ charge such that it experiences no force.
$<br/>\begin{array}{c}<br/>\therefore \frac{2\times 10^{-6}\times Q}{4\pi {\text{ to }}^2}=\frac{32\times 10^{-6}\times Q}{4\pi {\text{ fo }}_0(0.6-x{)}^2}\\ <br/>\text{ or, }16x^2=(0.6-x{)}^2\\ <br/>\text{ or, }4x=0.6-x\\ <br/>\therefore x=0.12m\\ <br/>\therefore x=12cm<br/>\end{array}<br/>$