試題詳解

18. When a switch is closed to complete a DC series RL circuit,
(A) the magnetic field outside the wires increases to a maximum value,
(B) the electric field in the wires increases to a maximum value,
(C) the rate of change of the electric and magnetic fields is greatest at the instant when the switch is closed,
(D) all of the above are true,
(E) only ( A ) and ( C ) above are true.