Question

1. By an aluminum cable passes a current of .3618 A to 12 volts, its temperature is 20.0 oC. The cable is then put in a place where its current changes to 0.4884 A at an unknown temperature. The resistivity of aluminum is and the temperature coefficient is 0.00429 oC-1. What's that unknown temperature?

Answer 1

(1) calculate the resistance of wire at T = 20 degree celcius by ohm's law;

V = IR;

resistance at unkown temperature T'

Resistance is varying with temperature as;