A positive and a negative charge are initially 50 mm apart. When they are moved close together so that they are now only 10 mm apart, the force between them will be________________?
Correct answer: D. 25 times larger than before
- A. 5 times smaller than before
- B. 5 times greater than before
- C. 10 times greater than before
- D. 25 times larger than before
Explanation
Coulomb's law gives force proportional to the inverse square of separation, F ∝ 1/r². Reducing the distance from 50 mm to 10 mm makes it five times smaller, so the force becomes 5² = 25 times greater.
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