The total amount of charge that has entered a wire at time $t$ is given by the expression $Q=(20 \mathrm{C})\left(1-e^{-\mu(20 \mathrm{v})}\right),$ where $t$ is in seconds and $t \geq 0$.
a. Graph $Q$ versus $t$ for the interval $0 \leq t \leq 10$ s.
b. Find an expression for the current in the wire at time $t$.
c. What is the maximum value of the current?
d. Graph $I$ versus $t$ for the interval $0 \leq t \leq 10$ s.