Closing an RL circuit

An ideal source of $9.0\mathrm{V}$, a resistor of $3.0\mathrm{\Omega }$ and an ideal inductor of $0.15\mathrm{H}$ are connected in series, and the switch is closed at time $t=0$. Compute the time constant and the current at time $t=0.10\mathrm{s}$.