An inductor with an inductance of L = 18.0 mH and a resistance of R = 4.33 12 is connected in series to the terminals of a battery with an EMF of E = 7.78 V (negligible internal resistance) and a switch that has been closed for a long time. At time t = 0, the battery is shorted to leave a discharging RL circuit. What is the time constant 7 for this RL circuit?