Q. When the speed of a dc motor increases the armature current
A) Increases
B) Decreases
C) Does not change
D) Increases and decreases continuously
Explanation
(b) With the increasing speed, $\omega$ increases. Thus current reduces due to increase in the back e.m.f.
Moreover $i = \frac{V - K\omega}{R}$. More $\omega$ will lead to the lesser current
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.