The current in a certain wire at 20. 0°C is 2. 40 A when the potential difference between the ends of the wire is 1. 50 V. If the wire is heated to 80. 0°C and the potential difference remains the same, the current decreases to 2. 00 A. (a) What is the resistance of the wire at 20. 0°C? At 80. 0°C? (b) What is the temperature coefficient of resistivity for the material of which this wire is made?