Question

In a given coil of self-inductance of 5 mH, current changes from 4 A to 1 A in 30 ms. Calculate the emf induced in the coil.

Answer 1

Self inductance, L=5 mH=5×10⁻³ HChange in current,

 dI=(1−4)=−3 A

Change in time, ${\displaystyle dt=30 ms=30\times 10-3 s}$

The emf induced in the coil is given by ${\displaystyle e=-L\frac{dI}{dt}}$

${\displaystyle \Rightarrow e=\frac{(-5\times {10}^{-3})\times (-3)}{30\times {10}^{-3}}}$

${\displaystyle \Rightarrow e=0.5 V}$