A long wire with a diameter D = 1 mm is immersed in an oil bath with a temperature Tr = 25°C. The wire has
an electrical resistance per unit length of Re=0.01 $/m. If the current I = 100 A flows in
the wire and the convection coefficient is h = 500 w/m?.K, what is the temperature of the wire if the regime
is permanent? From the moment the current is applied, how long will it take
so that the wire temperature is within 1°C of the steady state temperature?
The properties of the wire are p = 8000 kg/m3, c= 500 J/kg.K and ^ = 20 W/m.K.