Three point charges $q, q$ and $-2 q$ are placed at the corners of an equilateral triangle of side '$L$'. Calculate work done by extemal force in moving all the charges far apart without acceleration
Medium
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(a)
$U=\frac{k(q)(-2 q)}{L}+\frac{k(q)(q)}{L}+\frac{k(q)(-2 q)}{L}$
$U=\frac{-3 k q^2}{L}$
$U_{\infty}=0$
$W_{\text {ost }}=U_{-}-U=\frac{3 k q^2}{L}$
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