Q. Current in a coil changes from 5 A to 10 A in 0.2 s. If the coefficient of self-induction is 10 H, then the induced emf is
A) 112 V
B) 250 V
C) 125 V
D) 230 V
Explanation
(b) Induced emf in the coil is given by
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ e = \frac{L\ dI}{dt}$
Or $\ \ \ \ \ \ \ \ \ \ \ e = 10 \times \frac{(10 - 5)}{0.2}$
$\Rightarrow \ \ \ \ \ \ \ \ \ \ \ \ e = 250\ V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.