The induced emf produced in a coil is 8 V, when the current in the coil changes from 2 A to 4 A in \( 0.05 \) s. The self-inductance of the coil is:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \( 0.2 \) H
A changing current in a coil induces an emf in the same coil (self-induction), proportional to the rate of change of current: \( |e| = L\,dI/dt \).
\( \displaystyle \frac{dI}{dt} = \frac{4\,\mathrm{A} - 2\,\mathrm{A}}{0.05\,\mathrm{s}} = 40\,\mathrm{A\,s^{-1}} \)
\( \displaystyle L = \frac{|e|}{dI/dt} \)
\( \displaystyle L = \frac{8\,\mathrm{V}}{40\,\mathrm{A\,s^{-1}}} \)
\( \displaystyle L = 0.2\,\mathrm{H} \)
Note: The same question was also asked in CUET (UG) 2023 on 13-06-2023 (Slot 1).