(A) We can solve the problem by using Ohm's law, which states:
[tex]V=IR[/tex]
where
V is the potential difference across the electrical device
I is the current through the device
R is its resistance
For the heater coil in the problem, we know [tex]V=220 V[/tex] and [tex]R=220 \Omega[/tex], therefore we can rearrange Ohm's law to find the current through the device:
[tex]I= \frac{V}{R}= \frac{220 V}{220 \Omega}=1 A [/tex]
(B) The resistance of a conductive wire depends on three factors. In fact, it is given by:
[tex]R= \rho \frac{L}{A} [/tex]
where
[tex]\rho[/tex] is the resistivity of the material of the wire
L is the length of the wire
A is the cross-sectional area of the wire
Basically, we see that the longer the wire, the larger its resistance; and the larger the section of the wire, the smaller its resistance.
