Electric field

An electric field is produced by electrically charged particles. Electric fields are discussed in two branches in physics, electrostatics and electrodynamics. Electrostatics concerns unchanging electric fields, while electrodynamics concerns variations in electric fields. In addition, electronic fields have an effect on magnetic current. Electrical currents can be used to create a magnetic field, and magnetic fields can be used to create an electrical current. The equation for the strength of an electric field is E = F/q, where E is the energy of the electric field, F is the force of the particle, and q is the charge of the particle. The strength of an electric field is measured in newtons per coulomb, the units named in honor of Isaac Newton and Charles-Augustin de Coulomb, respectively.

Background

Danish physicist and chemist Hans Christian Ørsted (1777–1851) first noticed electrical fields affecting magnetism while giving a lecture at University of Copenhagen. When he passed an electrified wire over a magnetic compass, he noticed the compass needle moving. He then conducted experiments confirming the relationship between electricity and magnetism, showing that electrical fields produce a magnetic influence.

Michael Faraday (1791–1867), a British scientist, built off of Ørsted’s work in the 1820s. He developed the equation that describes the relationship between changes in a magnetic field and the electromotive force it induces in a circuit. This is known as Faraday’s law. He was the first to build an electric motor, which he used in his further experiments in developing electromagnets.

Electrical fields and magnetic fields are intertwined. Faraday’s work was expanded upon by Scottish mathematician James Clerk Maxwell (1831–79), who elaborated on the relationship between electricity and magnetism. Building upon Faraday’s law, Maxwell’s equations explicitly state the relationship between magnetism and electricity and show how magnetism and electricity interact and affect each other. Maxwell’s equations are the cornerstone of electromagnetic theory.

A German physics professor, Heinrich Hertz (1857–94), experimentally confirmed the work of Maxwell and Faraday. His experiments conclusively proved the existence of electromagnetic waves mathematically shown to exist by Maxwell.

Albert Einstein (1879–1955) and his contemporaries worked on grand unified theories. Such a theory is also known as the “theory of everything,” which unites all scientific formulas, showing how the equations work together and influence each other. Modern scientists speculate that such a theory could explain the origins and ending of the universe and existence. Electric fields play a role in these theories. Enlarging upon the equations posited by Maxwell and proven by Hertz, modern scientists have tried to incorporate all of the fundamental forces, such as magnetism, electricity, gravity, and nuclear forces; however, as of yet, they have been unable to do so.

Electric Fields Today

Electric fields are used in biology, medicine, engineering, physics, and the military. Animals use electrical fields for navigation. The human body requires electrical fields to function. Broadcast entertainment would not exist without the use of electrical fields. The military uses electrical fields in order to produce radio or signal jammers.

Many animals use electric fields in order to navigate. These animals possess abilities known as “electroreception” and “electrolocation.” Electroreception is the ability to perceive and utilize electrical stimuli in the environment. Electrolocation is the ability to generate an electric field and to sense objects around the animal. These abilities are most commonly found in aquatic animals, though bees and cockroaches have them as well. Fish use this ability to hunt for prey. Bees have shown an ability find flowers through electric fields produced by the flower. Cockroaches use electrolocation in order to find food. Other animals, such as the platypus, use electric fields to find prey.

The human body uses electric fields. The heart is controlled by electrical impulses from the brain. When the heart is unable to regulate its own electric impulses, many different ailments can occur. One commonly used treatment for an irregular heartbeat is a pacemaker, which stimulates the heart with an electrical pulse. Nerves also rely on electrical fields. A person’s nerves allow the body to understand external stimuli. Pain, pressure, and temperature are examples of sensations the nervous system recognizes. When the external stimulus activates the nerve, the nerve cells send electrical signals to the brain. The brain converts these electrical stimuli to chemical stimuli. As a result, the brain can understand the effects felt by the nervous system.

Electric fields are used for sending and receiving radio and television transmissions. Radio and television function because of electric fields. Antennas receive electric fields and convert them into intelligible signals such that people can be entertained. An antenna connected to a transceiver is capable of both sending and receiving radio signals. When the transceiver is sending signals out, it moves electrical charges to generate radio waves. If the transceiver is receiving signals, the radio waves it intercepts induce corresponding electrical and magnetic fields in the transceiver’s antenna. These electrical fields are then converted by one of several means into audio signal and/or visual display.

Radio jammers, which are illegal in the United States, also utilize electrical fields. Antennas can only use intelligible signals. A jammer functions by producing an electrical field that interferes with the signals being sent out by the antenna. The jammer’s signal is stronger than the transmitting antenna’s signal. As a result, the receiving cell phone, global positioning system (GPS) device, or radio is unable to detect the correct radio frequency and can only receive the interference emanating from the jammer. The jammer is only effective in the region where it is producing the strong signal. As the jammer moves away from the receiving antenna, the power of the electrical field weakens because it is spreading out over a wider area.

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