Question

A parallel-plate capacitor has 1.67 cm2 plates that are separated by 4.55 mm with air between them. If a 15.0 V battery is connected to this capacitor, how much energy does it store?


I used this equations and cannot get it right:

C=keA/d =[1*8.85E-12*(1.67^2*.455)]/4.55E-6 = 2.47E-6

E=.5CV^2 = .5*2.47E-6*15^2 = 2.78E-4