Coulomb's law gives the electrostatic force between two point charges as:
- F = k q₁ q₂ / r
- F = k q₁ q₂ / r²
- F = k (q₁ + q₂) / r²
- F = k q₁ q₂ r²
Show answer and solution
Correct answer: B. F = k q₁ q₂ / r²
1. F = k q₁ q₂ / r², where k = 1 / (4πε₀) ≈ 9 × 10⁹ N m² C⁻².
2. Inverse square in r, same as Newtonian gravity.
3. Force is along the line joining the charges; repulsive for like signs.
_Source: syllabus Physics Ch 1 §1.5 Coulomb's Law_