The immediate cause of many deaths is ventricular fibrillation, an uncoordinated

Question

The immediate cause of many deaths is ventricular fibrillation, an uncoordinated quivering of the heart, as opposed to proper beating. An electric shock to the chest can cause momentary paralysis of the heart muscle, after which the heart will sometimes start organized beating again. A defibrillator is a device that applies a strong electric shock to the chest over a time of a few milliseconds. The device contains a capacitor of a few microfarads charged to several thousand volts. Electrodes called paddles, about 8 cm across and coated with conducting paste, are held against the chest on both sides of the heart. Their handles are insulated to prevent injury to the operator, who calls. "Clear!" and pushes a button on one paddle to discharge the capacitor through the patient's chest. Assume an energy of 315 W s is to be delivered from a 26.0 µF capacitor. To what potential difference must it be charged?

=________ V

Explanation / Answer

If 1 Joule of energy is supplied in 1 second, then by definition, the rate of supply of energy is 1 Watt.
Therefore, 1 watt-second = 1 Joule.
So, in your Q., 315 Watt-seconds = 315 Joules.

Now when a capacitor of capacitance of F Farads is charged to an electric potential of V volts, the energy stored in that capacitor, E = (1/2).C.V

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