Question

Calculate the potential at a point due to a charge of $4\times {10}^{-7}C$ located at $0.09m$ away from it.

• A. $4\times {10}^{-4}V$
• B. $4\times {10}^{4}V$
• C. $7\times {10}^{4}V$
• D. $4\times {10}^{2}V$

Answer 1

Answer: (B)

$4\times {10}^{4}V$

Given,
$q_1=4\times {10}^{-7}C$, $r=0.09m$
Therefore, the potential due to the charge $q_1$ at the point is
$V=\frac{1}{4\pi {\epsilon }_0}\frac{q_1}{r}$
$=\frac{9\times {10}^9\times 4\times {10}^{-7}}{0.09}=4\times {10}^{4}V$