a charge Qis divided on two objects .what should be the values of charges on the object so that force between them is maximum.
Let q be the charge on first object and Q-q on other.
The electrostatic force, Fe = kq(Q-q)/r2.
To maximize the force, we must dFe/dq = 0
dFe/dq = kq(-1)/r2 + k(Q-q)/r2 = 0
q = Q - q
q = Q/2.
Hence to maximize the force, the should be one half on first and one half on other.