試題詳解

17. A coil with an inductance of 1.5 H and a resistance of 0.6 Ω is suddenly connected to a 12-V battery. Determine the time it takes for the current in the coil to reach 0.63 of its final value.
(A) 0.5 s,
(B) 1.0 s,
(C) 2.5 s,
(D) 4 s,
(E) 5 s.