When a switch is closed to complete a DC series RL circuit,
A) the electric field in the wires increases to a maximum value.
B) the magnetic field outside 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.

Question

Quizplus · Accepted Answer

When a switch is closed in a DC series RL circuit, the electric field in the wires indeed increases to a maximum value as current starts to flow. Simultaneously, the magnetic field outside the wires also increases to a maximum value due to the current. The rate of change of both the electric and magnetic fields is greatest at the instant the switch is closed because that's when the circuit transitions from no current (and thus no fields) to a state where current begins to flow, initiating the build-up of these fields. Therefore, all of the statements are true.

When a Switch Is Closed to Complete a DC Series