- Ans B but isn't -4q charge in equilibrium?
Thatipelly Sathwik last edited by
At that instant only force on 4q is zero. Since the force on other charges is not zero, they start moving immediately and the force on 4q won't be 0 later. So, we can't say that 4q is in equilibrium.
We say that a body is in equilibrium if it does not accelerate. But in this situation as soon as we release the charges, the other two charges move immediately and change the net force acting on the charge 4q thus accelerating it.