Question

In $0.2$ s, the current in a coil increases from $2.0$ A to $3.0A$. If inductance of coil is $60mH$, then induced current in external resistance of $3\Omega$ will be

• A. $1A$
• B. $0.5A$
• C. $0.2A$
• D. $0.1A$

Answer 1

The correct option is D $0.1A$

The potential difference gained across the inductor $=L\frac{di}{dt}=60\times {10}^{-3}\times \frac{3-2}{0.2}=0.3V$

This potential difference applied across an external resistance of $3\Omega$ would give a current $I=\frac{V}{R}=\frac{0.3V}{3\Omega }=0.1A$