The resistance of the
bulb is
(
)
2
2
220 V
484
100 W
V
R
=P
=
=
Ω
(b) The peak voltage of the source is
V
2
311
vm
V
=
=
(c) Since, P = I V
100 W
0 454A
220 V
�
�
�
P
I
V
 EXAMPLE 7 1
Rationalised 2023-24
181
Alternating Current
7 3 REPRESENTATION OF AC CURRENT AND VOLTAGE
BY ROTATING VECTORS — PHASORS
In the previous section, we learnt that the current through  a resistor is
in phase with the ac voltage