Part A The figure (Figure 1) shows a simplified circuit for a How long does it t
ID: 1659531 • Letter: P
Question
Part A The figure (Figure 1) shows a simplified circuit for a How long does it take to charge the capacitor to 6.0 V? Express your answer using two significant figures. photographic flash unit. This circuit consists of a 9.0-V battery, a 50.0-kOresistor, a 140 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 Submit My Answers Give Up Figure 1of 1 9.0 V 50.0 k 140FExplanation / Answer
The Voltage across capacitor at any time t is given by:
V = Vo*[1 - e^-(t/RC)]
6/9 = [1 - e^-(t/RC)]
3/9 = e^-(t/RC)
ln (1/3) = -t/RC
t = RC* ln 3.
= 50e3*140e-6 * ln 3
= 7.7 s answer