# To what potential difference must it be charged?

The immediate cause of many deaths is ventricular fibrillation, which is an uncoordinated quivering of the heart. An electric shock to the chest can cause momentary paralysis of the heart muscle, after which the heart sometimes resumes its proper beating. One type of defibrillator applies a strong electric shock to the chest over a time interval of a few milliseconds. This device contains a capacitor of several microfarads, charged to several thousand volts. Electrodes called paddles are held against the chest on both sides of the heart, and the capacitor is discharged through the patient's chest. Assume an energy of 320 J is to be delivered from a 30.0-µF capacitor. To what potential difference must it be charged?
V

asked Jan 27, 2012 in Physics

+1 vote

The formula for the potential energy of a capacitor is:

U = (1/2)*C*V^2  (where U = energy, C = capacitance, V =voltage)

Now solve for V:

V = squareroot (2*U / C)

plug in values and solve:

U = 320 J

C = 30*10^-6 F

V = squareroot (2*320 J / 30*10^-6 F)

V = 4618.8 V
answered Jan 28, 2012 by ~Expert~ (1,479 points)
selected Jan 28, 2012 by apush