Two point charges of 3 μC and 5 μC are placed 0.6 m apart in air. Taking N m²/C², what is the force between them?
Answer and explanation
Correct answer: C. 0.375 N
- Step 1: Coulomb's law gives N. Answer: 0.375 N. Why not the others: 0.225 N: multiplies by r instead of dividing by r². 0.135 N: forgets to divide by r². 1/24 N: uses k = 10^9 instead of 9 × 10^9.
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