A charge Q is divided into two charge q and Q-4 The value of q such that the force between them is maximum is

Explanation

Let q and `(Q-q)` be the charges on those bodies Force between the charges
`F= (1)/(4pi in_(0)) ((Q-q)q)/(r^(2))` For F to be maximum `(dF)/(dq)=0`
`(d)/(dq) (Q-q) q= 0 rArr (Q-q) + (-q) = 0`
`rArr Q -2q= 0, q= Q//2`. Thus the charge should be divided equally on teh objects.