A copper cable (k = 395 W/m.K) 30 mm in diameter carries a current of 300 A, when exposed to air at 30°C with convection coefficient of 20 W/m 2 .K. The cable resistance is 5 × 10 –3 Ω/m. Determine...

A copper cable (k = 395 W/m.K) 30 mm in diameter carries a current of 300 A, when exposed to air at 30°C with convection coefficient of 20 W/m².K. The cable resistance is 5 × 10^–3
Ω/m. Determine the surface and centre temperature of the cable.