6 mm diameter power line carries 40 A current and the resistanceof one meter is 0.02 ohms. Find the surface temperature of the wireon a day when the wind temperature is 10 ° C, the wind speed is 40km / h and it crosses the wire. Air characteristics: p = 1.246 kg /m3. k = 0.02439 W / m ° C. Pr = 0.7336, v = 1.426x10 m / s.(Electrical power, P = 1 * R).
