What are capacitors?

If a charged capacitor is connected in parallel to a chargeless capacitor of double capacitance, what will be the total loss of energy ?

Why is an insulator sometimes called a dielectric? What is the main difference between free and bound charge? Generally one of the two plates of a Capacitor System is earthed, why? Derive the expression for the energy stored in a charged capacitor.

Find an expression for the energy of a charged capacitor.

A charged capacitor is connected to an inductor at an instant of time t=0.If the capacitor and the inductor are taken to be pure, write down the equation of effective potential difference across the combination at any instant of time t and solve it for instantaneous current through I the combination.Explain brefly the exchange of electric and magnetic energy between the capacitor and the inductor.

Calculate the total capacity when three capacitors connected in series and parallel.