Question

An alternative voltage given by $V=140\left(\sin 314t\right)$ is connected across a pure resistor of $50\Omega$. Find
(i) The frequency of the source.
(ii) The rms current through the resistor.

Answer 1

(i)
If $V=140\sin 314t$
Comparing it with $V=V_0\sin \omega t$
$\omega =314$or $2\pi f=314$
or $f=314/2\pi =314/(2\times 3.14)=50Hz$
(ii)
$I_0=V_0/R=140/50=2.8A$
therefore $I_{rms}=I_0/\sqrt{2}=2.8/\sqrt{2}=1.98A$