An inductor, a resistor and a capacitor are joined in series with an ac source. The frequency of the source is slightly increased from a very low value. The reactance of the
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → inductor increases
The reactance of an inductor is \( X_L=\omega L \) and that of a capacitor is \( X_C=1/\omega C \). So the two change in opposite ways when the frequency is raised.
Option (1) inductor increases — Correct. \( X_L=\omega L \) grows in direct proportion to the frequency. So it increases as soon as the frequency is raised.
Option (2) resistor increases — Incorrect. A resistor has no reactance. Its resistance \( R \) does not depend on the frequency of the source.
Option (3) capacitor increases — Incorrect. \( X_C=1/\omega C \) becomes smaller when the frequency is raised.
Option (4) circuit increases — Incorrect. At a very low frequency \( X_C \) is much larger than \( X_L \). The net reactance \( X_C-X_L \) of the circuit therefore falls as the frequency rises from this value.
NCERT (2026-27):
AC Voltage Applied to an Inductor – “The inductive reactance is directly proportional to the inductance and to the frequency of the current.”