The strong and weak nuclear forces, the electromagnetic — or electrical — force, and gravity are thought to govern the universe. Electrical and gravitational forces are the only two types of these forces that have a macro range and thus interact with matter on a large scale. Chemical reactions, light, vision, and virtually all matter interactions are all governed by electromagnetism. Almost all technology relies on electricity to function, and the electrical force has several important aspects and measurements. The movement of electrons and the interactions of positive and negative electrical charges form the foundation of this force.
Positive and negative electric charges can exist in matter particles. The protons that make up an atom’s nucleus have a positive charge, while the electrons that orbit it have a negative charge. Because opposite charges attract each other in an attempt to neutralize charge and like charges repel, putting the opposite poles of two magnets together causes the magnets’ ends to pull toward each other. At its most basic level, electricity is the movement of electrons from one location to another in a static discharge or an electronic circuit; electricity can only flow where a conductive path is available.
Because an electric current and a magnetic field can create each other, the electromagnetic force is named after them. Due to the repulsion of the electrical force, passing a magnet through a coil of wire causes the electrons in the wire to move away from the magnet. Similarly, due to electrical inertia, running an electric current through a coiled wire produces a magnetic field in the opposite direction of the current.
Most of the behavior that electricity exhibits when interacting with objects is governed by two main measurements of electrical force: voltage and resistance, from which the measurement for current is derived. Similar to the pressure built up inside an activated water hose, voltage is the amount of electrical potential that exists from one point to another. The greater the electrical pressure and the easier it is for current to flow between two points, the higher the voltage between them. The term “resistance” refers to an object’s ability to resist electrical current flow. The voltage divided by the resistance in ohms can be used to calculate the electrical current in amperes that flows from one point to another.
Alternating current and direct current are two types of electrical current. The difference is in the flow direction; alternating current with reversed polarities switches directions dozens of times per second. Because direct current maintains polarity, it can only flow in one direction, as in a battery.