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# Charging and Discharging a Capacitor

EANDM-WHKAM7

In the RC circuit below the switch is connected to A, at time $t = 0$, after being connected to B for a long time. The capacitor charges for $45 \:\text s$, then the switch is moved quickly to B ($t’ = 0$) and the capacitor begins to discharge.

The circuit parameters are: $\Delta V = 9 \:\text V$, $R_1 = 100 \:\text k \Omega$, $R_2 = 60 \:\text k \Omega$, and $C= 880 \: \mu \text F$.

What is the charge on the capacitor after $60 \:\text s$ of discharging ($t’ = 60\:\text s$)?

A

$0.0072 \:\text {mC}$

B

$0.72 \:\text {mC}$

C

$1.41 \:\text {mC}$

D

$1.60 \:\text {mC}$

E

$2.07 \:\text {mC}$