Question

If instantaneous current is given by $i = 4\cos(\omega t + \varphi)$ 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

Answer 1

Answer: (B)

$2\sqrt{2}$ amperes

Answer 2

$i_{r.m.s.} = \frac{i_{o}}{\sqrt{2}} = \frac{4}{\sqrt{2}} = 2\sqrt{2}\mspace{6mu} ampere$