Question

The electric current in a circuit is given by $i=3\sin \omega t+4\cos \omega t$. The rms current is:

• A. $\frac{5}{\sqrt{2}}$
• B. $5$
• C. $\frac{4}{\sqrt{2}}$
• D. $\frac{3}{\sqrt{2}}$

Answer 1

The correct option is A $\frac{5}{\sqrt{2}}$

$i_{rms}=\sqrt{\frac{{i_1}^2+{i_2}^2}{2}}$

$=\sqrt{\frac{9+16}{2}}$

$=\sqrt{\frac{25}{2}}$

$=\frac{5}{\sqrt{2}}$