Electricity and Magnetism: Key Concepts and Devices for Physics Students

Charging by Contact

The process of transferring charge by touching or rubbing two objects together. Charging by Friction / The transfer of electrons from one uncharged object to another by rubbing the objects together. Charging by Induction / The rearrangement of electrons on a neutral object caused by a nearby charged object without physical contact.

Ohm's Law

The relationship between voltage, current, and resistance, stated as V = I \times R.

Current

The net movement of electric charges in a single direction through a conductor.

Amperes

The unit used to measure electric current ($A$).

Ohms

The unit used to measure electrical resistance ($\Omega$).

Resistance

The tendency for a material to oppose the flow of electrons, changing electrical energy into thermal energy and light.

Potential Difference

The difference in electrical potential energy between two places in an electric circuit; also known as voltage.

Voltage

A measure of the electrical potential energy provided by an electric source, measured in Volts ($V$).

Parallel Circuit

An electric circuit with two or more paths through which charges can flow.

Series Circuit

An electric circuit with only one path through which charges can flow.

Alternating Current

Electric current that reverses its direction of flow in a regular pattern.

Direct Current

Electric current that flows in only one direction through a wire.

Capacitor

A device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator.

Electromagnetic Induction

The process of creating a current in a circuit by changing a magnetic field.

Magnetic Domains

Groups of atoms with aligned magnetic poles.

Transformer

A device that increases or decreases the voltage of an alternating current.

Faraday Cage

An enclosure used to block electromagnetic fields.

Electromagnet

A temporary magnet made by wrapping a wire coil carrying a current around an iron core.

Motor

A device that converts electrical energy into mechanical energy.

Generator

A device that converts mechanical energy into electrical energy by rotating a wire coil in a magnetic field.