A defibrillator is a medical device that stores energy in the electric field of a capacitor; it can be used to stop the random contractions (cardiac fibrillation) in heart attack victims. When fibrillation occurs, the heart produces a rapid, irregular pattern of beats. A fast discharge of energy through the heart can return the organ to its normal beat pattern. Because the capacitor must charge between applications, a medical worker must wait before administering a second discharge.
Consider the following parameters for the RC circuit in a defibrillator: C = 30.5 µF and R = 48.4 kΩ. The circuitry in the charging system applies 5000 V to the RC circuit to charge it.
(a) Find the time constant of the circuit, the maximum charge on the capacitor, the maximum current in the circuit during the charging process, and the charge and current as a function of time.
(b) Find the energy stored in the capacitor when it is fully charged.