Video narration
If you double the distance between two charges, does the force become half as strong? Not quite. Coulomb's Law gives the electrostatic force between two stationary point charges. Like charges repel; unlike charges attract. The formula gives magnitude; the signs give direction. F = k|q1q2|/r2. Force grows with either charge, but falls with the square of separation. In vacuum, k is approximately 9 × 109 N·m2/C2. Now the exam shortcut: double r, and force becomes F/4. Triple r, F/9. Double both charges, and force becomes 4F. That's the turn: the formula becomes a rapid NEET shortcut. Quick MCQ: if distance doubles, is the force double, half, one-fourth, or four times? Correct answer: one-fourth. Practise more on the Krita NEET JEE App. So no-doubling distance makes force one-fourth, because Coulomb's Law follows an inverse-square relationship.