1) A 4.7-mu or micro FF capacitor is charged to 290 V. How much energy is stored in the capacitor?
2) How much additional energy is required to charge the capacitor from 290 V to 780 V?
U = 1.2*C*V2
The Attempt at a Solution
The first one I got right...
1) U = 1/2*(4.7 * 10-6)*290 = 1.975E-1
2) I thought to find this one you could use the change in energy would have to equal the change in potential? So I tried this...but its not right, can anyone tell me where I went wrong? thanks!
Uf - 1.975E-1 = .5*(4.7E-6)(780)2 - .5*4.7E-6*2902
Uf = 1.4297 J