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MHT CET 2021 (22 Sep, Shift 1) · Electric Charge & Coulomb's Law

Electric Charge & Coulomb's Law question from MHT CET 2021 (22 Sep, Shift 1)

Q55MHT CET 2021 · 22 SEP · SHIFT 1Easy

Electric Charge & Coulomb's Law

A point charge QQ is placed at the centre of the line joining two equal point charges +q+q and +q+q. The value of QQ if the system of the charges is in equilibrium, is

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Answer: (b)

  1. For an end charge +q+q (separation 2r2r): kq2(2r)2+kqQr2=0\dfrac{kq^2}{(2r)^2} + \dfrac{kqQ}{r^2} = 0.
  2. Q=−q4Q = -\dfrac{q}{4}
  3. So the answer is (b) −q4-\dfrac{q}{4}.
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