Final answer:
The correct answer to the phenomenon of heat being absorbed or evolved due to current flowing in a conductor with a temperature gradient is the Thermoelectric effect, specifically the Peltier effect.
The phenomenon in which heat is absorbed or evolved when current flows in a conductor with a temperature gradient is known as:
a. Joule heating
Step-by-step explanation:
The phenomenon where heat is absorbed or evolved when current flows in a conductor with a temperature gradient is known as the Thermoelectric effect. This effect encompasses both the Peltier and Seebeck effects.
The Peltier effect refers to the heating or cooling of an electrical junction of two different conductors when a current is passed through it.
It's observed that good conductors of electricity, which include metals like copper and aluminum, are generally also good conductors of heat due to the kinetic energy transfer between colliding particles — energy that eventually manifests as heat within the material when electrons moving through the conductor collide with the particles of the material.
When current flows in a conductor with a temperature gradient, heat is either absorbed or evolved. This phenomenon is known as Joule heating. It occurs due to the resistance encountered by the electrons as they move through the conductor, resulting in the transfer of kinetic energy and an increase in temperature.