A 50 Hz alternating current is flowing in a 28 mH coil. The reactance of the coil is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 8.8\,\Omega \)
The opposition of a coil to an alternating current is its inductive reactance, which grows in proportion to the frequency.
\( X_L = \omega L = 2\pi \nu L \)
\( L = 28\,\mathrm{mH} = 28\times10^{-3}\,\mathrm{H} = 0.028\,\mathrm{H} \)
\( X_L = 2 \times 3.14 \times 50\,\mathrm{Hz} \times 0.028\,\mathrm{H} = 314 \times 0.028\,\Omega \)
\( X_L = 8.79\,\Omega \approx 8.8\,\Omega \)
Note: NTA picked this question from an NCERT (2026-27) example and changed the figures. Do not ignore NCERT while practising numericals.
NCERT (2026-27):
AC Voltage Applied to an Inductor – …
