Question

If the instantaneous value of current is $I=2\cos (\omega t+\theta )$ ampere in an A.C. circuit, the r.m.s. value of current in ampere will be :

• A. $2$
• B. $\sqrt{2}$
• C. $2\sqrt{2}$
• D. zero

Answer 1

The correct option is B $\sqrt{2}$

$I=2cos(\omega +\theta )$

$I_{rms}=\frac{I_o}{\sqrt{2}}=\frac{2}{\sqrt{2}}$

$=\sqrt{2}A$