Question

What is the electric potential at the centre of square of side $1$ m? The charges $1\times {10}^{-8}C,-2\times {10}^{-8}C,3\times {10}^{-8}C$ and $2\times {10}^{-8}C$ are placed at the corners of the square.

• A. $205V$
• B. $308V$
• C. $509V$
• D. $110V$

Answer 1

The correct option is C $509V$

$x=L\frac{\sqrt{2}}{2}=\frac{L}{\sqrt{2}}$

$=\frac{1}{\sqrt{2}}m$

potential $0:-\frac{K(q_1+q_2+q_3+q_4)}{x}$

$=\frac{K\times ({10}^{-8}+(-2)\times {10}^{-8})+(3\times {10}^{-8})+(2\times {10}^{-8})}{x}$

$=\frac{9\times {10}^9\times 4\times {10}^{-8}}{\frac{1}{\sqrt{2}}}$

$=509$ volt