Question

Two charged particles, placed at a distance d apart in vacuum, exert a force F on each other. Now, each of the charges is doubled. To keep the force unchanged, the distance between the charges should be changed to_____
Fill in the blank with the correct answer from the options given below.

• A. 4d
• B. 2d
• C. d
• D. $\frac{d}{2}$

Answer 1

Answer: (B)

2d

Answer 2

According to Coulomb’s law, $F = \frac{k q_1 q_2}{d^2}$​​. When charges are doubled, the distance must increase by a factor of 2 to keep the force constant.