Translations of Encyclopedia about Physics

Electricity and Magnetism

How are electricity and magnetism created?

Electricity has a direct relation to magnetism.

Both phenomena have their origin in the positive and negative charges of atoms.

Atoms maintain a neutral charge when in a static or calm state. In this case, the positively charged protons and negatively charged neutrons appear in the same number in atoms and their combined forces are balanced.

With the addition of energy, atoms can either release or gain new electrons, where the addition of energy creates a positive charge within the atom and a loss of energy creates a negatively charged atom. In such cases the atom is transformed into a charged ion. Ions which have few electrons attract to themselves loose electrons, where ions with an excess of electrons repel loose electrons. These phenomena are referred to as electrical charges.

The movement of electrically charged particles of a substance (conductor) is defined as electrical current. Not all substances have the ability to conduct electrical current, which means that not all substances enable to movement of free or loose electrons.

Substances which have the quality of being able to conduct electrical current are referred to as conductors, where those substances which are not able to conduct electrical current are referred to as non-conductors. All metals are considered good conductors, a characteristic which many non-metal compounds also have.

All electrical effects are created by electrical charges which affect one another through electrostatic forces. The area in which these forces act is called an electrical field. Charges with the same potential repel one another where charges with opposite potential are attracted to one another.

Besides this, each moving electrical charge creates a magnetic field. This principle does not apply only for the flow of current within a conductor but applies on an atomic level as well. Electrons which revolved around an atom’s nucleus generate a magnetic moment which, with many substances, makes the atoms behave as small rod magnets (elementary magnets).

With many substances, these elementary magnets are lined in the same direction and make the substance a constant magnet.

With other substances, such as iron, the elementary magnets balance under the influence of a magnetic field, as such increasing the strength of the that field. This effect is used with electromagnets. After removing such a substance from the magnetic field, the substance remains magnetic for only a short time.

If the elementary magnets within some object are uniformly oriented, the above stated effect repels an object with uniform orientation elementary magnets while attracting objects with non-uniform elementary magnet. A magnetic field exists around such objects.

Electricity and magnetism are presently used in many areas, where not only electrical and electronic appliances operate on the principle of electricity and magnetism but where radio, television and mobile transmitters use artificially generated electromagnetic waves. Today, we can find control and regulation units in almost all mechanical machinery, such as in automobiles, washing machines and microwave ovens.

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