It is called root mean square (rms)
current and is donoted by I:
0 707
2
m
m
i
I
i
=
=
Similarly, the rms voltage is defined by
0 707
2
m
m
v
V
v
=
=
We have P = IV = I 2R
3 An ac voltage v = vm sin wt applied to a pure inductor L, drives a current
in the inductor i = im sin (wt – p/2), where im = vm/XL