Question

Four point charges of $ +3 \mu C, +2 \mu C, + 3 \mu C $ and $ +2 \mu C $ are placed at the corners of a rectangle $ A, B, C $ and $ D $ . The electrical force will be least between the charges

• A. $ A $ and $ D $
• B. $ B $ and $ D $
• C. $ A $ and $ C $
• D. $ C $ and $ D $

Answer 1

Answer: (B)

Electrical force between two charges is given by $F=\frac{k\,q_{1}q_{2}}{r^{2}}$
Force will be least if the value $q_{1}q_{2}$ is small and separation between the two is large
For rectangle, $AD=BC; AB=CD; AC=BD$
Also, $AC>\, AD$ and $AC >\, AB$
$\therefore $ Electrostatic force will be least between the charges $B$ and $D$