Question: A tungsten wire has a radius of 0.070 mm and is heated from 20.0 to 1405 oC. The temperature coefficient of resistivity is α = 4.5 x 10-3 (Co)-1. When 150 V is applied across the ends of the hot wire, a current of 1.8 A is produced.
Question 1: How long is the wire?
I need help to find how long is the wire and neglect any effects due to thermal expansion of the wire.