The current voltage (I – V) graphs for a given metallic wire at two different temperatures T1 and T2 are shown in figure. If follows from the graphs that
It is clear from figure that at a given voltage V0 the current I1 in the wire at temperature T1 is greater than the current I2 in the wire at temperature T2, Therefore the resistance of the wire at temperature T1 is less than that of temperature T2. This can happen if T1 is less than T2 because the resistance of wire increases with increase in temperature