A charge of 4 is to be divided into two. The distance between the...

If after division, one of the charge is $q$ the other charge will be \left(4 - q\right)$. The force between them can be written as,</p><p>$F = \dfrac{Kq\left(4 - q\right)}{{d}^{2}}$</p><p>For the force between them to be maximum,</p><p>$\dfrac{dF}{dq} = 0 ⇒ \dfrac{K}{{d}^{2}}\left[4 - 2q\right] = 0$</p><p>$⇒ q = 2\mu C