To find the value of current through the resistor, we
apply Kirchhoff’s loop rule 
∑ε( )t =
0 (refer to Section
3 13), to the circuit shown in Fig 7 1 to get
=
vmsin
t
i R
ω
or   
vmsin
i
t
R
ω
=
Since R is a constant, we can write this equation as
msin
i
i
ωt
=
(7