Question

The work done in placing a charge of $8\times {10}^{-18}$ coulomb on a condenser of capacity $100$ micro-farad is:

• A. $16\times {10}^{-32}$ joule
• B. $3.2\times {10}^{-26}$ joule
• C. $4\times {10}^{-10}$ joule
• D. $32\times {10}^{-32}$ joule

Answer 1

The correct option is D $32\times {10}^{-32}$ joule

Here the work done $=$ energy stored in capacitor $=\frac{Q^2}{2C}$
or, $W=\frac{(8\times {10}^{-18}{)}^2}{2\times 100\times {10}^{-6}}=32\times {10}^{-32}J$