Q. A coil of inductance 0.2 H and 1.0 W resistance is connected to a 90 V source. At what rate will the current in the coil grow at the instant the coil is connected to the source?
A) 450 $As^{- 1}$
B) 4.5 $As^{- 1}$
C) 45 $As^{- 1}$
D) 0.45 $As^{- 1}$
Explanation
(a) From $e = L\ dI/dt$
$\frac{dI}{dt} = \frac{e}{L} = \frac{90}{0.2} = 450\ As^{- 1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.