In a DC system, what is the effect of an inductor?

In a DC system, an inductor primarily influences the behavior of current flow over time. The most significant effect of an inductor in a DC circuit is that it opposes changes in current due to its property of inductance. When a DC source is first applied, the inductor temporarily acts like an open circuit; it resists the sudden change in current. However, once a steady state is reached and the current stabilizes, the inductor does allow full current flow through it, essentially acting as a short circuit after the initial transient period.

Thus, the correct answer highlights that during the initial moments when a DC voltage is applied to an inductor, it behaves as an open circuit due to the induced electromotive force opposing the change in current. This phenomenon can be critical in understanding how inductors function in circuits, particularly during switching or in transient conditions, before they settle into a steady state where current can flow freely.