Question

Find the electric field and potential at the centre of a square of side $d=10cm$. Four identical charges of $q=2\mu C$ each are kept at the four corners of a square.

• A. ${10}^{6}V$.
• B. ${10}^{8}V$.
• C. ${10}^{7}V$.
• D. ${10}^{9}V$.

Answer 1

The correct option is A ${10}^{6}V$.

Electric field at centre due to each charge cancels the other, (see figure) so net electric field will be zero at the centre but,

As,

Potential is scalar quantity so it will be added so,

Potential at centre $=4\left[\frac{K\left(2\mu c\right)}{\frac{a}{\sqrt{2}}}\right]$

$=4\left[\frac{9\times {10}^9\times 2\times {10}^{-6}\times \sqrt{2}}{10\times {10}^{-2}}\right]$

$={10}^6$ Volt