Help with a capacitor question?

A capacitor is not the most efficient device for storing energy. Batteries can store more energy in much less space. For example, a typical 12 V automobile battery stores on the order of 1.00 * 10^6 J.

(a) Find the capacitance necessary to store 1.00 *10^6 J with a potential difference of 1.00 *10^4 V across the capacitor's terminals.

(b) Suppose that such a capacitor was made in the form of a parallel-plate capacitor with a vacuum between the plates and an electric field no greater than 7.00* 10^6 V/m. What is the minimum area of the plates?