Question

A charge of $-30\mu C$ is placed at $50cm$ from another charge of $+25\mu C$ in vacuum. The force between them is:

• A. $60N$
• B. $27N$
• C. $90N$
• D. $120N$

Answer 1

The correct option is B $27N$

$q_1=-30\times {10}^{-6}$, $q_2=25\times {10}^{-6}$ and $r=.5$

$F=\frac{k{q}_1{q}_2}{r^2}=27N$