3. Example No1:
A 1000W heating element is connected to a
250v AC supply voltage. Calculate the
resistance of the element when it is hot and
the amount of current taken from the supply.

4. Power =
I V
∴Current, I
=
P / V
=
1000 / 250
=
4 A

5. Resistance, R
=
V / I
=
250 / 4
=
62.5Ω

6. Example No2:
Calculate the power being consumed by a
100Ω resistor connected to a 240V supply.
As there is only one component connected to
the supply, the resistor, then VR = Vs.

7. Current, I
=
VR / R
=
240 / 100
=
2.4 A

8. Power consumed,P =
I2
R
=
2.4 2 x 100
=
576 W