PHYS 102 Lecture Notes - Electric Field, Joule Heating, Temperature Coefficient

• School: McGill University
• Department: Physics
• Course: PHYS 102
• Professor: Zaven Altounian

Document Summary

In metals, the valence electrons are very weakly attached to their parent atoms. These electrons can be considered to be free . If an electric field is applied, the free electrons will move in the direction of the force applied on them. The electric current is the rate of flow of charge across a surface. The direction of the electric current is defined as the direction of movement of a positive charge. For free electrons, this energy is transformed into kinetic energy. Typically, the free electrons acquire speeds of the order of 10^6 m/s. But the directions of the velocities are random i. e. no net movement of the charges. When an electric field is applied, the free electrons move in a direction opposite to the electric field with velocities of the order of 10^-3 m/s. The larger the potential difference, the larger the current inside the conductor.