Question

A wire of diameter D= 2 mm and uniform temperature T has an electrical

resistance of 0.01Ω /m and a current flow of 20 A.

a) What is the rate at which heat is dissipated per unit length of wire? What is

the heat dissipation per unit volume within the wire?

b) If the wire is not insulated and is in ambient air and large surroundings for

which T∞= Tsur= 20oC, what is the temperature T of the wire? The wire

has an emissivity of 0.3, and the coefficient associated with heat transfer

by natural convection may be approximated by an expression of the form,

h= C[(T- T∞)/D]1/4, where C= 1.25 W/m7/4 K

5/4

.

Answer 1

The answer to your question is provided below