Q1. A certain car battery with a 14.0 V emf has an initial charge of 195 A•h. Assuming that the potential across the terminals stays constant until the battery is completely discharged, for how long in hours can it deliver energy at the rate of 184 W?
Q2. The immediate cause of many deaths is ventricular fibrillation that is an uncoordinated quivering of the heart. An electric shock to the chest can reason for momentary paralysis of the heart muscle, after which heart sometimes resumes its proper beating. One type of defibrillator (photo below) applies a strong electric shock to the chest over a time interval of a few milliseconds. This device contains a capacitor of numerous microfarads, charged to several thousand volts. Electrodes called paddles are held against the chest on both sides of the heart, and capacitor is discharged through the patient's chest. Suppose energy of 270 J is to be delivered from a 30.0-µF capacitor. To what potential difference must it be charged?