Q. In 0.1 s, the current in a coil increases from 1A to 1.5 A. If inductance of coil is 60mH, then induced current in external resistance of $3\Omega$ will be
A) 1 A
B) 0.5 A
C) 0.2 A
D) 0.1 A
Explanation
(d) Induced emf,$|e| = L\frac{di}{dt}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \left( 60 \times 10^{- 3} \right) \times \frac{(1.5 - 1)}{0.1}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = \ \frac{60 \times 10^{- 3} \times 0.5}{0.1}$
= 0.3 V
Induced current,
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ i = \frac{e}{R} = \frac{0.3}{3} = 0.1\ A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.