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Moderate

Current from a Discharging Capacitor

EANDM-N8@GWN

The capacitor charge, $Q_C$ as a function of time, $t$, while a capacitor is discharging is given by:

$$Q_C = Q_0 { e }^{ -\frac { t }{ \tau } }$$

...where $Q_0$ is the initial charge on the capacitor and $\tau$ is the time constant.

What is the current in the discharge circuit at $t=3 \:\text s$ if $\tau = 1.8 \:\text s$ and $Q_0 = 57 \:\text {mC}$?

A

$0 \:\text A$

B

$6.0 \:\text A$

C

$10.3 \:\text {mA}$

D

$5.98 \:\text {mA}$

E

$34.2 \:\text {mA}$