How things work college course/Electricity and Field theory

For an introduction to the purpose and scope of this work see Talk:How_things_work_college_course/Electricity_and_Field_theory

Outline

 * Electricity
 * Electricity is the motion of charged particles (usually electrons)
 * Electrons have potential energy due to electric forces. Potential energy is associated with these forces, and the fact that energy is involved that makes electricity useful.
 * To understand energy we we need to introduce the concept of fields.


 * Fields
 * Wind velocity and air temperature are defined on Earth's atmosphere.
 * Three other important fields are electric potential, electric field, and magnetic field. The first two can be defined by analogy with gravity.
 * There are two ways to visually represent vector fields: A spatial distribution of vectors, and field lines.
 * The most common way to represent a scalar field is the use of contours.


 * The gravitationa analogy (first of two analogies)
 * F = mg like F=qE
 * PE = Fd if force is uniform and parallel to displacement
 * PEG = m(gh) = m&phi;, where &phi;=gh is gravitational potential.
 * PE = qEd = q(Ed), where V=Ed is gravitational potential (replace h=height by d=distance)
 * Inverse square
 * (advanced sum over sources)
 * Electric fields are rarely uniform. Need examples