Two point charges, +2 μC and +3 μC, are separated by 0.1 m in vacuum. What is the magnitude of the electrostatic force between them? (k = 9 × 10⁹ N·m²/C²)
Show the answer and explanation
Correct answer
A. 5.4 N
Principle or equation
Coulomb's law: F = k|q1q2|/r².
Why this answer is correct
q1 = 2×10⁻⁶ C, q2 = 3×10⁻⁶ C, r = 0.1 m. F = 9×10⁹ × (6×10⁻¹²) / (0.01) = 9×10⁹ × 6×10⁻¹⁰ = 5.4 N.
Example
Two 1 μC charges 0.1 m apart: F = 9×10⁹ × 10⁻¹² / 0.01 = 0.9 N.
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