Q. A motor having an armature of resistance $2\Omega$ is designed to operate at $220\ V$ mains. At full speed, it develops a back e.m.f. of $210\ V$. When the motor is running at full speed, the current in the armature is
A) $5A$
B) $105A$
C) $110A$
D) $215A$
Explanation
(a) $i = \frac{E - e}{R} = \frac{220 - 210}{2} = \frac{10}{2} = 5A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.