Work Problem 17.21 for the case of aluminum rather than copper. The resistivity of aluminum is 2:83    ohm-cm. Problem 17.21 Copper wire having a diameter of 3/16 in. is insulated with a 4-in. layer...

Work Problem 17.21 for the case of aluminum rather than copper. The resistivity of aluminum is 2:83
 ohm-cm.

Problem 17.21

Copper wire having a diameter of 3/16 in. is insulated with a 4-in. layer of material having a thermal conductivity of 0:14 Btu/h ft
F: The outer surface of the insulation is maintained at 70F: How much current may pass through the wire if the insulation temperature is limited to a maximum of 120F? The resistivity of copper is
 ohm-cm.