10. A 1.50-m cylindrical rod of diameter 0.500 cm is connected to a power supply that maintains a constant potential difference of 15.0 V across its ends, while an ammeter measures the current through it. We observe that at room temperature (20.0 C) the ammeter reads 18.5 A, while at 92.0 C it reads 17.2 A. We can ignore any thermal expansion of the rod. Find a. the resistivity at 20.0 C and b. the temperature coefficient of resistivity at 20.0 C for the material of the rod