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MHT CET 2023 (11 May, Shift 1) · Electrostatic Potential Energy

Electrostatic Potential Energy question from MHT CET 2023 (11 May, Shift 1)

Q41MHT CET 2023 · 11 MAY · SHIFT 1Medium

Electrostatic Potential Energy

Three point charges +q,+2q+q, +2q and +Q+Q are placed at the three vertices of an equilateral triangle. If the potential energy of the system of three charges is zero, the value of QQ in terms of qq is

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Answer: (a)

  1. All three pairs are at the same distance aa, so U=ka(q⋅2q+2q⋅Q+q⋅Q)U = \frac{k}{a}(q\cdot 2q + 2q\cdot Q + q\cdot Q).
  2. U=0⇒2q2+3qQ=0U = 0 \Rightarrow 2q^2 + 3qQ = 0
  3. Q=−2q3Q = -\frac{2q}{3}
  4. So the answer is (a) Q=−2q3Q = -\frac{2q}{3}.
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