Question

A piece of cloud having area $25\times {10}^6{m}^2$ and electric potential of ${10}^5$ volts. If the height of cloud is 0.75 km, then energy of electric field between earth and cloud will be

• A. 250 J
• B. 750 J
• C. 1225 J
• D. 1475 J

Answer 1

The correct option is D 1475 J

Energy $=\frac{1}{2}{ϵ}_0{E}^2\times (A\times d)=\frac{1}{2}{ϵ}_0\left(\frac{V^2}{d^2}\right)Ad$
$=\frac{1}{2}\times \frac{8.85\times {10}^{-12}\times ({10}^5{)}^2\times 25\times {10}^6}{0.75\times {10}^3}=1475J$