Q. If instantaneous current is given by $i = 4\cos{(\omega t + \phi)}\ amperes$, then the $r.m.s$ value of current is
A) 4 amperes
B) $2\sqrt{2}$ amperes
C) $4\sqrt{2}$ amperes
D) Zero amperes
Explanation
(b) $i_{r.m.s.} = \frac{i_{0}}{\sqrt{2}} = \frac{4}{\sqrt{2}} = 2\sqrt{2}\ ampere$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.