An inductor coil stores \(64\mathrm{J}\) of magnetic field energy and dissipates energy at the rate of \(640\mathrm{W}\)…

An inductor coil stores \(64\mathrm{J}\) of magnetic field energy and dissipates energy at the rate of \(640\mathrm{W}\) when a current of 8 A is passed through it. If this coil is joined across an ideal battery, find the time constant of the circuit in _______ seconds.

[JEE Main 2021, 26 Aug (Shift 1)]