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MHT CET 2026 (13 May, Shift 1) · Electrostatic Potential Energy

Electrostatic Potential Energy question from MHT CET 2026 (13 May, Shift 1)

Q14MHT CET 2026 · 13 MAY · SHIFT 1Medium

Electrostatic Potential Energy

Three point charges $+q, -2q$ and $-2q$ are placed at the vertices of an equilateral triangle of side a. The work done by some external force to increase their separation to ' $2a$ ' will be $\left(K = \frac{1}{4\pi\varepsilon_0}\right)$

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Answer: (d)

Initial PE: $U_i = \frac{K}{a}\left[(q)(-2q) + (q)(-2q) + (-2q)(-2q)\right] = \frac{K}{a}(-2q^2 - 2q^2 + 4q^2) = 0$
At side $2a$ the same bracket gives $U_f = 0$ .
$W = U_f - U_i = 0$
So the answer is (d) zero.

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