Two point charges, +2 μC and +3 μC, are separated by 0.5 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. 0.216 N
Principle or equation
Coulomb's law: F = k |q1 q2| / r².
Why this answer is correct
F = (9×10⁹) * (2×10⁻⁶) * (3×10⁻⁶) / (0.5)² = (9×10⁹ * 6×10⁻¹²) / 0.25 = (54×10⁻³) / 0.25 = 0.216 N.
Example
For 1 μC and 1 μC at 1 m, F = 9×10⁻³ N.
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