A 1.60 cylindrical rod of diameter 0.550 is connected to a power supply that maintains a constant potential difference of 15.0 across its ends, while an ammeter measures the current through it. You observe that at room temperature (20.0 ) the ammeter reads 18.3 , while at 92.0 it reads 17.4 . You can ignore any thermal expansion of the rod.
Find the temperature coefficient of resistivity at 20 for the material of the rod.