Question

Calculate the amount of work done required in moving $14\times {10}^{20}$ electrons across two points of a wire with a potential difference of $28V$.

• A. $3132J$
• B. $6227J$
• C. $6272J$
• D. $3136J$

Answer 1

The correct option is C $6272J$

Given:
Potential difference, $V=28V$
No. of electrons, $n=14\times {10}^{20}$
Magnitude of charge on an electron, $e=1.6\times {10}^{-19}C$

So total charge that has to be moved is:
$Q=ne$
$Q=14\times {10}^{20}\times 1.6\times {10}^{-19}C$
$Q=224C$

Work done in moving this amount of charge,
$W=VQ$
$W=28V\times 224C$
$W=6272J$