The time constant for an RL circuit is given by:
[tex]\tau=\frac{L}{R}[/tex]In this case the inductance is 62 mH and the resistance is 25 Ohms, then we have:
[tex]\begin{gathered} \tau=\frac{62\times10^{-3}}{25} \\ \tau=2.48\times10^{-3} \end{gathered}[/tex]Therefoe, the atime constant is 0.00248 seconds
