Question

What is the electric potential at a distance of 9 cm from 3 nC ?

• A. 270 V
• B. 3 V
• C. 300 V
• D. 30 V

Answer 1

Answer: (C)

Given: $r=9cm=0.09m$
Charge $Q=3nC=3\times 10^{-9}C$
Potential at a distance
$9cm,V=\frac{kQ}{r}$ where $k=9\times 10^9$
$\therefore V=\frac{9\times 10^9\times 3\times 10^{-9}}{0.09}=300V$