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 $Q_0 = 57 \:\text {mC}$?