Question

Two charges each of $1\mspace{6mu} coulomb$are at a distance $1km$ apart, the force between them is

• A. $9 \times 10^{3}\mspace{6mu} Newton$
• B. $9 \times 10^{- 3}\mspace{6mu} Newton$
• C. $1.1 \times 10^{- 4}\mspace{6mu} Newton$
• D. $10^{4}\mspace{6mu} Newton$

Answer 1

Answer: (A)

$9 \times 10^{3}\mspace{6mu} Newton$

Answer 2

$F = \frac{kQ^{2}}{r^{2}} = 9 \times 10^{9} \times 1^{2} \times \frac{1}{(1000)^{2}} = 9 \times 10^{3}N$