Question
Find the time required for $50\,Hz$ alternating current to change its value from zero to maximum value.
✓
Answer
${\rm{I}} = {{\rm{I}}_0}{\rm{sin}}\,\omega {\rm{t}}$
$ \Rightarrow \mathrm{I}_{0}=\mathrm{I}_{0} \sin \omega \mathrm{t} $
$ \Rightarrow \sin \omega \mathrm{t}=1 $
$\Rightarrow \omega \mathrm{t}=\frac{\pi}{2}$
$ \Rightarrow 2 \pi \mathrm{ft}=\frac{\pi}{2} \Rightarrow \mathrm{t}=\frac{1}{200}, \mathrm{s}=5 \mathrm{\,ms} $
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