Question

A charge of $1 \, \mu C$ is divided into two parts such that their charges are in the ratio of $2:3$ . These two charges are kept at a distance $1 \, m$ apart in vacuum. Then, the electric force between them (in $N$ ) is -

• A. $0.216$
• B. $0.00216$
• C. $0.0216$
• D. $2.16$

Answer 1

Answer: (B)

$\frac{q_{1}}{q_{2}}=\frac{2}{3}$
$q_{1} \, + \, q_{2} \, = \, 1μC$
$\Rightarrow $ $q_{1} \, = \, \frac{2}{5}\mu C \, , \, q_{2}= \, \frac{3}{5}μC$
$F \, = \, \frac{K q_{1} q_{2}}{r^{2}}$
$\text{F} = \frac{9 \times 1 0^{9} \times \frac{2}{5} \times \frac{3}{5} \times 1 0^{- 1 2}}{\left(1\right)^{2}}$
$= 0.00216 \, \text{N}$