I have several questions about capacitor's concepts. Q1)What does battery really do in charging a capacitor? Q2)Uncharged capacitor doesn't mean the plates don't have any charges? Q3)During charging,the developing electric field between the plates does have any effect in charging? Q4)When charging is progressed,battery has to do more and more work until the potential difference becomes same.Is this right? Energy stored in a capacitor of capacitance C:Let small work done dW to move a charge dq from one plate to another plate.Then at an instant let V be the potential difference of the capacitor and q be the charge in the plates. => dW=V.dq =>dW=q/C.dq =>Integrating the above equation by q=0 to q=Q,then we get W=(Q^2*C)/2 I don't understand this derivation. Does a charge actually move from one plate to another within capacitor? There is another derivation which also I cannot understand.It is about moving a plate by a small distance and calculating work.But I don't understand why someone moves that plate to move by about a small distance.Also it says electric field acting on one plate is σ/2ε and not σ/ε.Because one plate is held stationary and the other is moving .So it experiences attractive force of the other plate and it's own attraction to the other plate.And while determining the force, the latter term should be used right? I am sorry but I am pretty weak in Physics.