A certain charge Q is divided into two parts q and Q-q . How the charge Q and q must be related so that when q and (Q-q) is placed at a certain distance apart experience maximum electrostatic repulsion?

Question

Quantrex Academy · Accepted Answer

Correct answer: A. Q=2 q

The electrostatic force of repulsion between the charge q and (Q-q) at separation r is given by F=(1)/(4 π _0) (q(Q-q))/(r^2)=(1)/(4 π _0) (q Q-q^2)/(r^2) If F is maximum, then ∂ F / ∂ q=0 i.e. (1)/(4 π _0) · ((Q-2 q))/(r^2)=0 As (1)/(4 π _0 r^2) is constant, therefore Q-2 q=0 or Q=2 q

A certain charge Q is divided into two parts q and Q-q . How the...

Options

Correct answer

Step-by-step solution

More from Electrostatics