Question

Q: A 2-mm-diameter electrical wire is insulated by a 2-
mm-thick rubberized sheath (k = 0.13 W/mK), and the
wire/sheath interface is characterized by a thermal
contact resistance of Rc = 3 X 10-4 m2K/W. The
convection heat transfer coefficient at the outer surface of
the sheath is 10 W/
m2K, and the temperature of the
ambient air is 20°C. If the temperature of the insulation
should not exceed 50°C, what is the maximum allowable
electrical power that may be dissipated per unit length of
the conductor? What is the critical radius of insulation?​

Answer 1

Answer:

such a very difficult question...