Question

A cylindrical wire with a radius r has a thermal conductivity. The fluid outside the wire has a mean temperature

t and a heat transfer coefficient ℎ/h. The wire gets hot when it carries current due to its electrical conductivity.

Which property is responsible for the wire getting hot when carrying current?

a) Thermal conductivity
b) Fluid temperature
c) Wire radius
d) Heat transfer coefficient

Answer 1

The heat generation in a wire when carrying current is due to its electrical conductivity, which causes Joule heating due to electron collisions within the material.

Step-by-step explanation:

The property responsible for a wire getting hot when carrying current is its electrical conductivity. When an electrical current flows through a conductor, such as a cylindrical wire, the movement of electrons through the material causes collisions with the atomic lattice, which in turn generates heat due to increased kinetic energy of the atoms. This phenomenon is known as Joule heating or resistive heating. Although thermal conductivity affects the rate at which heat is dissipated from the wire to the surrounding environment, and the fluid temperature and heat transfer coefficient may influence the cooling of the wire, they are not responsible for the generation of heat when an electric current is present.