Question

If point charges $Q_{1}=2 \times 10^{-7} C$ and $Q_{2}=3 \times 10^{-7} C$ are at $30 cm$ separation, then find electrostatic force between them

• A. $6\times 10^{-3} N$
• B. $2\times 10^{-3} N$
• C. $3\times 10^{-3} N$
• D. $8\times 10^{-3} N$

Answer 1

Answer: (A)

$\because$ Electrostatic force, $F=k \frac{Q_{1} Q_{2}}{r^{2}} $
$=9 \times 10^{9} \times \frac{2 \times 10^{-7} \times 3 \times 10^{-7}}{\left(30 \times 10^{-2}\right)^{2}}$
$=6 \times 10^{-3} N $