Exam-style question
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If the distance between two charges is doubled, how does the force between them change according to Coulomb's law?.
- A.The force doubles.
- B.The force quadruples.
- C.The force halves.
- D.The force decreases to a quarter of its original value.
Model answer
What a good answer should say
- The force decreases to a quarter of its original value.
Explanation
Why this works
According to Coulomb's law, the force is inversely proportional to the square of the distance between the charges. If the distance is doubled, the force becomes 1/(2^2) = 1/4 of its original value.
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