The current in a coil changes from \(3 \mathrm{~A}\) to \(1 \mathrm{~A}\) in \(0.1 \mathrm{~s}\) in a coil…
The current in a coil changes from \(3 \mathrm{~A}\) to \(1 \mathrm{~A}\) in \(0.1 \mathrm{~s}\) in a coil of self-inductance \(8 \mathrm{mH}\). The emf induced in the coil is
\(16 \mathrm{~V}\)
\(1.6 \times 10^{-2} \mathrm{~V}\)
\(16 \times 10^{-2} \mathrm{~V}\)
\(2 \mathrm{~V}\)
Solution
Change in currents in the coil
\(\Delta I=(3-1) \mathrm{A}=2 \mathrm{~A}\)
Time interval, \(\Delta t=0.1 \mathrm{~s}\)
Self induction, \(L=8 \mathrm{mH}=8 \times 10^{-3} \mathrm{H}\)
\(\therefore\) Induced emf in the coil,
\(e=L \frac{d I}{d t}=L \frac{\Delta I}{\Delta t}=8 \times 10^{-3} \times \frac{2}{0.1}=16 \times 10^{-2} \mathrm{~V}\)