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For songs called Electricity is a property of Matter that results from the presence or movement of Electric Charge . Together with Magnetism , it constitutes the Fundamental Interaction known as Electromagnetism . Electricity is responsible for many well-known Physical phenomena such as Lightning , Electric Field s and Electric Current s, and is put to use in Industrial applications such as Electronics and Electric Power . CONCEPTS IN ELECTRICITY In casual usage, the term electricity is applied to several related concepts that are better identified by more precise terms:
HISTORY Ancient According to Thales Of Miletus , writing at around 600 BC , a form of electricity was known to the Ancient Greeks who found that rubbing Fur on various substances, such as Amber , would cause a particular Attraction between the two. The Greeks noted that the amber buttons could attract light objects such as Hair and that if they rubbed the amber for long enough they could even get a Spark to jump. An object found in Iraq in 1938 , dated to about 250 BC and called the Baghdad Battery , resembles a Galvanic Cell and is believed by some to have been used for Electroplating . Modern Italian physician the English scientist William Gilbert , in ''De Magnete'', expanded on Cardano's work and coined the Modern Latin word ''electricus'' from ''ηλεκτρον'' (''elektron''), the Greek word for "amber", which soon gave rise to the English words ''electric'' and ''electricity''. He was followed in 1660 by Otto Von Guericke , who invented an early Electrostatic generator. Other European pioneers were Robert Boyle , who in 1675 stated that electric attraction and repulsion can act across a vacuum; Stephen Gray , who in 1729 classified materials as Conductor s and Insulator s; and C. F. Du Fay , who first identified the two types of electricity that would later be called ''positive'' and ''negative''. The Leyden Jar , a type of Capacitor for electrical energy in large quantities, was invented at Leiden University by Pieter Van Musschenbroek in 1745 . William Watson , experimenting with the Leyden jar, discovered in 1747 that a discharge of static electricity was equivalent to an Electric Current . In June, 1752 , Benjamin Franklin promoted his investigations of electricity and theories through the famous, though extremely dangerous, Experiment of flying a Kite during a Thunderstorm . Following these experiments he invented a Lightning Rod and established the link between Lightning and electricity. If Franklin did fly a kite in a storm, he did not do it the way it is often described (as it would have been dramatic but fatal). It was either Franklin (more frequently) or Ebenezer Kinnersley of Philadelphia (less frequently) who created the convention of positive and negative electricity. Franklin's observations aided later scientists such as Michael Faraday , Luigi Galvani , Alessandro Volta , André-Marie Ampère , and Georg Simon Ohm whose work provided the basis for modern electrical technology. The work of Faraday, Volta, Ampere, and Ohm is honored by society, in that fundamental units of electrical measurement are named after them. Volta discovered that Chemical Reaction s could be used to create positively charged Anode s and negatively charged Cathode s. When a conductor was attached between these, the Difference In The Electrical Potential (also known as voltage) drove a Current between them through the conductor. The Potential Difference between two points is measured in units of Volt s in recognition of Volta's work. In 1800 Volta constructed the first device to produce a large electric current, later known as the Electric Battery . Napoleon , informed of his works, summoned him in 1801 for a command performance of his experiments. He received many medals and decorations, including the Legion Of Honor . By the end of the 19th century Electrical Engineer s had became a distinct profession, separate from physicists and inventors. They created companies that investigated, developed and perfected the techniques of electricity transmission, and gained support from goverments all over the world for starting the first worldwide electrical telecomunication network, the Telegraph Network . Pioneers in this field included Werner Von Siemens , founder of Siemens AG in 1847 , and John Pender , founder of Cable & Wireless. The late 19th and early 20th century produced such giants of electrical engineering as Nikola Tesla , inventor of the polyphase Induction Motor ; Samuel Morse , inventor of the telegraph; Antonio Meucci , an inventor of the telephone; Thomas Edison , inventor of the first commercial electrical energy distribution network; George Westinghouse , inventor of the electric Locomotive ; Charles Steinmetz , theoretician of alternating current; Alexander Graham Bell , another inventor of the telephone and founder of a successful telephone business. The rapid advance of electrical technology in the latter 19th and early 20th centuries led to commercial rivalries, such as the so-called War Of The Currents between Edison's direct-current system and Westinghouse's alternating-current method. Often, concurrent research in widely scattered locations led to multiple claims to the invention of a device or system. ELECTRIC CHARGE See Also: Electric charge Electric charge is a property of certain Subatomic Particle s (e.g., Electron s and Proton s) which interacts with Electromagnetic Fields and causes attractive and repulsive Force s between them. Electric charge gives rise to one of the four . ELECTRIC FIELD See Also: Electric field The concept of electric field was introduced by Michael Faraday . The electrical field force acts between two charges, in the same way that the Gravitational Field force acts between two Mass es. However, the electric field is a little bit different. Gravitational force depends on the masses of two bodies, whereas electric force depends on the electric charges of two bodies. While gravity can only pull two masses together, the electric force can be an attractive ''or'' repulsive force. If both charges are of same sign (e.g. both positive), there will be a repulsive force between the two. If the charges are opposite, there will be an attractive force between the two bodies. The magnitude of the force varies inversely with the square of the distance between the two bodies, and is also proportional to the product of the unsigned magnitudes of the two charges. ELECTRIC POTENTIAL See Also: Electric potential The electric potential difference between two s indicate the direction of heat flows. Similarly, there is an electric potential at every point in space, and its Gradient in the electric field indicates where charges move. ELECTRIC CURRENT See Also: Current (electricity) An Electric Current is a flow of Electric Charge , and its intensity is measured in Ampere s. Examples of electric currents include metallic conduction, where Electron s flow through a Conductor such as a metal Wire , and Electrolysis , where Ion s (charged Atom s) flow through liquids. The particles themselves often move quite slowly, while the Electric Field that drives them propagates at close to the Speed Of Light . See '' Electrical Conduction '' for more information. Devices that use charge flow principles in materials are called Electronic Devices . A Direct Current (DC) is a unidirectional flow, while an Alternating Current (AC) reverses direction repeatedly. The time average of an alternating current is zero, but its energy capability ( RMS value) is not zero. Ohm's Law is an important relationship describing the behaviour of electric currents, relating them to Voltage . For historical reasons, electric Current is said to flow from the most positive part of a circuit to the most negative part. The electric current thus defined is called '' Conventional Current ''. It is now known that, depending on the conditions, an electric current can consist of a flow of charged particles in either direction, or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation. If another definition is used - for example, "electron current" - it should be explicitly stated. Electrical energy is energy stored in an Electric Field or transported by an Electric Current . Energy is defined as the ability to do Work , and electrical energy is simply one of the many types of energy. Examples of electrical energy include:
ELECTRIC POWER See Also: Electric power Electric power is the rate at which electrical energy is produced or consumed, and is measured in Watt s (symbol: W). A Fossil-fuel or Nuclear Power Station converts heat to electrical energy, and the faster the station burns fuel, assuming constant efficiency of conversion, the higher its power output. The output of a power station is usually specified in megawatts (millions of watts). The electrical energy is then sent over Transmission Line s to reach the consumers. Every consumer uses appliances that convert the electrical energy to other forms of energy, such as Heat (in Electric Arc Furnace s and Electric Heater s), Light (in Light Bulb s and Fluorescent Lamp s), or motion, i.e. Kinetic Energy (in Electric Motor s). Like the power station, each appliance is also rated in watts, depending on the rate at which it converts electrical energy into another form. The power station must produce electrical energy at the same rate as all the connected appliances consume it. In electrical engineering, the concepts of Apparent Power and Reactive Power are also used. Apparent power is the product of RMS voltage and RMS current, and is measured in volt-amperes (VA). Reactive Power is measured in volt-amperes-reactive (VAR). Non-nuclear electric power is categorized as either green or brown electricity. Green power is a cleaner alternative energy source in comparison to traditional sources, and is derived from renewable energy resources that do not produce any nuclear waste; examples include energy produced from wind, water, solar, thermal, hydro, combustible renewables and waste. Electricity from coal, oil, and natural gas is known as traditional power or "brown" electricity. SI ELECTRICITY UNITS SEE ALSO Engineering Safety Electrical phenomena in nature
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