Q 220

A 2.0-μF capacitor that is initially uncharged is charged through a 50-kΩ resistor.How long does it take for the capacitor to reach 90% of its full charge?
A)0.90 s
B)0.23 s
C)2.2 s
D)2.3 s

Q 221

A fully charged 37-µF capacitor is discharged through a 1.0-kΩ resistor.If the voltage across the capacitor is reduced to 7.6 volts after just 20 ms,what was the original potential across the capacitor?
A)16 V
B)13 V
C)11 V
D)9.0 V
E)8.0 V

Q 222

A 2.0-μF capacitor is charged to 12 V and then discharged through a 4.0-MΩ resistor.How long will it take for the voltage across the capacitor to drop to 3.0 V?
A)8.0 s
B)11 s
C)22 s
D)24 s