Question: What is electricity?
Answer: electricity is a set of physical phenomena associated with the presence and movement of charged particles.
All materials are composed of one or more elements. An element is a material made up of one type of atom. Elements are often identified by the number of protons and electrons in one atom of the element. A hydrogen atom, for example, has only one electron and one proton. An aluminum atom has 13 electrons and 13 protons. An atom with an equal number of electrons and protons is electrically neutral.
Electrons in the outer band of an atom can be easily displaced by the application of external force. When an electron is forced out of an atom, the atom it leaves behind has more protons than electrons.
This atom now has a positive charge. Atoms or molecules of a material can also have an excess of electrons, giving the material a negative charge. A positive or negative charge is caused by an absence or excess of electrons. The number of protons remains constant.
Electrons can move easily from one atom to another in some materials. In other substances, it is difficult to get electrons to move. But in any case, we can move electrons a lot more easily than we can move protons. Electricity almost always results, in some way, from the motion of electrons in a material.
Electrons are much lighter than protons or neutrons. In fact, compared to the nucleus of an atom, the electrons weigh practically nothing.
The flow of free electrons in a material from one atom to the next atom in the same direction is referred to as current and is designated by the symbol I. The amount of current flowing is determined by the number of electrons that pass through a cross-section of a conductor in one second.
In an electrical conductor, the electrons “jump” from atom to atom, predominantly from negatively charged locations toward positively charged locations. In a typical electrical circuit, many trillions, quadrillions, or quintillions of electrons pass a given point every second.
It takes about 10^24 atoms to fill one cubic centimeter of a copper conductor. This means that trying to represent even a small value of current as electrons would result in an extremely large number.
The letter A is the symbol for amps. A current of one amp means that in one second about 6.24 x 10^18 electrons move through a cross-section of conductor.
The force required to make electricity flow through a conductor is called a difference in potential, electromotive force (emf), or voltage. Voltage is designated by the letter E or the letter V. The unit of measurement for voltage is the volt which is also designated by the letter V.
A voltage can be generated in various ways. A battery uses an electrochemical process. A car’s alternator and a power plant generator utilize a magnetic induction process. All voltage sources share the characteristic of an excess of electrons at one terminal and a shortage at the other terminal. This results in a difference of potential between the two terminals.
We can conclude that electricity is a type of energy fueled by the transfer of electrons from positive and negative points within a conductor.