My physics class is not a calculus based class; therefore, the formulas you see here will not be calculus. My problem states: A parallel-plate capacitor has 3.56 cm^2 plates that are separated by 6.08 mm with air between them. The permittivity of a vacuum is 8.85419e-12 C^2/Nm^2. If a 10.4 V battery is connected to this capacitor, how much energy dies it store. Answer in units of J. Capacitance between parallel plates: C = (epsilon * A)/d (epsilon is the permittivity of a vacuum.) Once you have capacitance, you can figure the stored energy using: U = 1/2CV^2 A = 3.56 cm^2 = 3.56e-4 m^2 d = 6.08 mm = .00608 m Epsilon = 8.85419e-12 C^2/Nm^2 V = 10.4 Plugging the above numbers into the formula: U = (1/2)((epsilon * A)/d)(V^2) I get 9.9811e-15 J, but the answer is wrong. Am I missing something here or just flat out working the problem wrong?