Identify the correct statement(s) among the following.
A. In a d.c. circuit, a capacitor can conduct but not an inductor.
B. In a d.c. circuit, an inductor can conduct but not a capacitor.
C. In a d.c. circuit, both the inductor and capacitor cannot conduct.
D. An inductor has infinite resistance in a d.c. circuit.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → B only
For steady d.c. the frequency is zero. The reactances are \( X_L = \omega L \) and \( X_C = 1/\omega C \), so at \( \omega = 0 \) an inductor offers no reactance and a capacitor offers infinite reactance.
(A) In a d.c. circuit, a capacitor can conduct but not an inductor. — Incorrect. Once charged, a capacitor blocks steady current, because the gap between its plates is an insulator.
(B) In a d.c. circuit, an inductor can conduct but not a capacitor. — Correct. After the current becomes steady there is no induced emf in the inductor, and it acts as an ordinary conducting wire.
(C) In a d.c. circuit, both the inductor and capacitor cannot conduct. — Incorrect. The inductor does conduct.
(D) An inductor has infinite resistance in a d.c. circuit. — Incorrect. Its opposition to d.c. is only the small resistance of its wire (zero for an ideal inductor); the infinite value belongs to a capacitor.