Q. Self-inductance of a coil is $50\ mH$. A current of $1\ A$ passing through the coil reduces to zero at steady rate in $0.1\ \sec$., the self-induced $emf$ is
A) 5 volts
B) 0.05 volts
C) 50 volts
D) 0.5 volts
Explanation
(d) $L = 50 \times 10^{- 3}H$
$\frac{dI}{dt} = \frac{(1 - 0)}{0.1} = 10$
$\varepsilon = \frac{L.dI}{dt} = 50 \times 10^{- 3} \times 10 = 50 \times 10^{- 2} = 0.5\ volt$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.