Q. A coil of resistance $400\Omega$ is placed in a magnetic filed. If the magnetic flux $\phi(wb)\ $linked with the coil varies with time t (sec) as $\phi = 50t^{2} + 4$. The current in the coil at $t = 2$ sec is
A) $0.5\ A$
B) $0.1\ A$
C) $2\ A$
D) $1\ A$
Explanation
(a) Induced e.m.f. $\varepsilon = \frac{d\phi}{dt} = - (100t)$
Induced current $i$ at $t = 2\ sec$
$= \left| \frac{\varepsilon}{R} \right| = + \frac{100 \times 2}{400} = + 0.5\ Amp$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.