Two point charges of −4 μC and +2 μC are separated by 0.3 m. What is the magnitude of the force between them? Use k = 8.99 × 10⁹ N·m²/C².
A0.80 N
B0.24 N
C4.0 N
D80 N
Explanation
📌 F = k|q₁q₂|/d² = (8.99×10⁹)(4×10⁻⁶)(2×10⁻⁶)/(0.3)² = 71.92×10⁻³/0.09 = 0.80 N. Force is attractive (unlike charges).