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MHT CET 2026 (12 May, Shift 1) · Electrostatic Potential Energy

Electrostatic Potential Energy question from MHT CET 2026 (12 May, Shift 1)

Q7MHT CET 2026 · 12 MAY · SHIFT 1Medium

Electrostatic Potential Energy

The equal charges (say 'q') are placed at a distance of 4r4r and a third charge (−2q)(-2q) is placed at a mid-point. The potential energy of the system is (ϵ0=\epsilon_0 = permittivity of free space)

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Answer: (c)

  1. Pairs: (q,q)(q, q) at 4r4r; two pairs (q,−2q)(q, -2q) at 2r2r.
  2. U=k[q24r−2q22r−2q22r]=−7kq24rU = k\left[\dfrac{q^2}{4r} - \dfrac{2q^2}{2r} - \dfrac{2q^2}{2r}\right] = -\dfrac{7kq^2}{4r}
  3. U=−7q216πϵ0rU = -\dfrac{7q^2}{16\pi\epsilon_0 r}. So the answer is (c).
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