Question

Two points A and B are located in diametrically opposite directions of a point charge of +2 $\mu$ C at distances 2 m and 1 m respectively from it. The potential difference between A and B is

• A. $3\times {10}^3$ V
• B. $6\times {10}^4$ V
• C. $-9\times {10}^3$ V
• D. $-3\times {10}^3$ V

Answer 1

Answer: (C)

$-9\times {10}^3$ V

Here $q=2\mu C=2\times {10}^{-6}C,r_A=2m,r_B=1m$
$\therefore V_A-V_B=\frac{q}{4\pi {\epsilon }_0}[\frac{1}{r_A}-\frac{1}{r_B}]=2\times {10}^{-6}\times 9\times {10}^9[\frac{1}{2}-\frac{1}{1}]V=-9\times {10}^{3}V$