NEET 2019 · PhysicsCoulomb forcePrevious Year Question
Two point charges A and B, having charges +Q and −Q respectively, are placed at a certain distance apart and the force acting between them is F. If 25% of the charge of A is transferred to B, then the force between the charges becomes
Answer: (B) 9F/16. Answer: (b) Solution: Original force: F = k·Q·Q/d² = kQ²/d².
- A.F
- B.9F/16✓
- C.16F/9
- D.4F/3
Correct Answer
(B) 9F/16
Solution & Explanation
Answer: (b) Solution: Original force: F = k·Q·Q/d² = kQ²/d². Transfer 25% of A's charge (0.25Q) to B: New charge on A = Q − 0.25Q = +0.75Q New charge on B = −Q + 0.25Q = −0.75Q New force magnitude: F' = k·(0.75Q)(0.75Q)/d² = k·0.5625Q²/d² = (9/16)·kQ²/d² F' = (9/16)F.
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