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MHT CET 2024 (15 May, Shift 2) · Electric Charge & Coulomb's Law

Electric Charge & Coulomb's Law question from MHT CET 2024 (15 May, Shift 2)

Q29MHT CET 2024 · 15 MAY · SHIFT 2Medium

Electric Charge & Coulomb's Law

Two point charges +q1+q_1 and q2q_2 repel each other with a force of 100 N. q1100\text{ N}.\ q_1 is increased by 10%10\% and q2q_2 is decreased by 10%10\%. If they are kept at their original positions the change in the force of repulsion between them is

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Answer: (d)

  1. F∝q1q2F \propto q_1q_2 at fixed distance.
  2. F′=(1.1 q1)(0.9 q2) kr2=0.99F=99 NF' = (1.1\,q_1)(0.9\,q_2)\,\dfrac{k}{r^2} = 0.99F = 99\text{ N}
  3. Change =99−100=−1 N= 99 - 100 = -1\text{ N}. So the answer is (d) decreased by 1 N.
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