Circuits with capacitors
The figure (attached) shows a simplified circuit for a photographic flash unit. This circuit consists of a 9.0 V battery, an R = 45.0 k resistor, a 140 µF capacitor, a flashbulb, and two switches. Initially, the capacitor is uncharged and the two switches are open. To charge the unit, switch S1 is closed; to fire the flash, switch S2 (which is connected to the camera’s shutter) is closed. How long does it take to charge the capacitor to 5.5 V?