Category: Basic Physical Concepts

Basic Physical Concepts

Nonelectrical Energy

Nonelectrical Energy

In electricity and electronics, there are phenomena that involve other forms of energy besides electrical energy. Visible light is an example. A light bulb converts electricity into radiant energy that you can see. This...

Electromotive Force

Electromotive Force

Current can only flow if it gets a “push.” This can be caused by a buildup of static electric charges, as in the case of a lightning stroke. When the charge builds up, with...

Static Electricity

Static Electricity

Charge carriers, particularly electrons, can build up, or become deficient, on things without flowing anywhere. You’ve experienced this when walking on a carpeted floor during the winter, or in a place where the humidity...

Current

Current

Whenever there is movement of charge carriers in a substance, there is an electric current. Current is measured in terms of the number of electrons or holes passing a single point in 1 second....

Semiconductors

Semiconductors

In a semiconductor, electrons flow, but not as well as they do in a conductor. Some semiconductors carry electrons almost as well as good electrical conductors like copper or aluminum; others are almost as...

Resistors

Resistors

Some substances, such as carbon, conduct electricity fairly well but not really well. The conductivity can be changed by adding impurities like clay to a carbon paste, or by winding a thin wire into...

Insulators

Insulators

An insulator prevents electrical currents from flowing, except occasionally in tiny amounts. Most gases are good electrical insulators. Glass, dry wood, paper, and plastics are other examples. Pure water is a good electrical insulator,...

Conductors

Conductors

In some materials, electrons move easily from atom to atom. In others, the electrons move with difficulty. And in some materials, it is almost impossible to get them to move. An electrical conductor is...

Molecules

Molecules

When atoms of elements join together to form a compound, the resulting particles are molecules. above figure is an example of a molecule of water, consisting of three atoms put together. The natural form...

Compounds

Compounds

Different elements can join together to share electrons. When this happens, the result is a chemical compound. One of the most common compounds is water, the result of two hydrogen atoms joining with an...

Ions

Ions

If an atom has more or less electrons than protons, that atom acquires an electrical charge. A shortage of electrons results in positive charge; an excess of electrons gives a negative charge. The element’s...

Electrons

Electrons

Surrounding the nucleus of an atom are particles having opposite electric charge from the protons. These are the electrons. Physicists arbitrarily call the electrons’ charge negative, and the protons’ charge positive. An electron has...

Isotopes and Atomic Weights

Isotopes and Atomic Weights

For a given element, such as oxygen, the number of neutrons can vary. But no matter what the number of neutrons, the element keeps its identity, based on the atomic number. Differing numbers of...

Atoms

Atoms

All matter is made up of countless tiny particles whizzing around. These particles are extremely dense; matter is mostly empty space. Matter seems continuous because the particles are so small, and they move incredibly...