Q114 / 150 · MHT CET 2023 (11 May Shift 1) · Physics
When a current of $1 \mathrm{~A}$ is passed through a coil of 100 turns, the flux associated with it is $2.5 \times 10^{-5} \mathrm{~Wb} /$ turn. The self inductance of the coil in millihenry is
- A$40$
- B$25$
- C$4$
- Correct answerD$2.5$
Solution
Given: $N=100, I=1 \mathrm{~A}$, $\phi=2.5 \times 10^{-5} \mathrm{~Wb} /$ turn
Self-inductance of coil,
$$
\begin{aligned}
\mathrm{L} & =\frac{\mathrm{N} \phi}{\mathrm{I}} \\
\therefore \quad \mathrm{L} & =\frac{100 \times 2.5 \times 10^{-5}}{1}=2.5 \times 10^{-3} \mathrm{H}=2.5 \mathrm{mH}
\end{aligned}
$$
Hence, the correct answer is option: 'D'.