Q. Electric charges of $+ 10\mu C, + 5\mu C,\ - 3\mu C\ and + 8\mu C$ are placed at the corners of a square of side $\sqrt{2}m.$ the potential at the centre of the square is
A) $1.8\ V$
B) $1.8 \times 10^{6}\ V$
C) $1.8 \times 10^{5}\ V$
D) $1.8 \times 10^{4}\ V$
Explanation
(c) [image:1_image279.wmf]Length of each side of square is $\sqrt{2}m$ so distance of it’s centre from each corner is $\frac{\sqrt{2}}{\sqrt{2}} = 1m$
Potential at the centre
$V = 9 \times 10^{9}\left\lbrack \frac{10 \times 10^{-}6}{1} + \frac{5 \times 10^{- 6}}{1} - \frac{3 \times 10^{- 6}}{1} + \frac{8 \times 10^{- 6}}{1} \right\rbrack$
$= 1.8 \times 10^{5}\ V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.