Question

Calculate the potential at a point $P$ due to a charge of $4\times 10^{-7}$ C located $9cm$ away

• A. $8\times 10^{-5}V$
• B. $8\times 10^{4}V$
• C. $4\times 10^{4}V$
• D. $4\times 10^{-4}V$

Answer 1

Answer: (C)

$V=\frac{1}{4\pi {\epsilon }_0}\cdot \frac{Q}{r}$
$=9\times 10^{9}N{m}^{-2}{C}^{-2}\times \frac{4\times 10^{-7}}{0.09m}C$
$=4\times 10^{4}V$