Q. When the current changes from +2 A to -2 A in 0.05 s, an emf of 8 V is induced in a coil. The coefficient of self-induction of the coil is
A) 0.2 H
B) 0.4 H
C) 0.8 H
D) 0.1 H
Explanation
(d) Induced emf, $e = - L\frac{di}{dt} = - L\frac{( - 2 - 2)}{0.05}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ 8 = L\frac{(4)}{0.05}$
$\therefore\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ L = \ \frac{8 \times 0.05}{4} = 0.1\ H$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.