Physics
Electricity
Electricity is a form of energy resulting from the movement of charged particles, such as electrons. It is a fundamental aspect of physics and plays a crucial role in various natural phenomena and technological applications. The study of electricity encompasses concepts like electric fields, electric currents, and electrical circuits, and is essential for understanding the behavior of matter at the atomic and molecular levels.
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11 Key excerpts on "Electricity"
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Learning Press(Publisher)
• Electric potential : the capacity of an electric field to do work on an electric charge, typically measured in volts. • Electromagnetism : a fundamental interaction between the magnetic field and the presence and motion of an electric charge. The most common use of the word Electricity is less precise. It refers to: • Electric power provided commercially by the electrical power industry. In a loose but common use of the term, Electricity may be used to mean wired for Electricity which means a working connection to an electric power station. Such a connection grants the user of Electricity access to the electric field present in electrical wiring, and thus to electric power. Electrical phenomena have been studied since antiquity, though advances in the science were not made until the seventeenth and eighteenth centuries. Practical applications for Electricity however remained few, and it would not be until the late nineteenth century that engineers were able to put it to industrial and residential use. The rapid expansion in electrical technology at this time transformed industry and society. Electricity's extraordinary versatility as a source of energy means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is the backbone of modern industrial society, and is expected to remain so for the foreseeable future. History Thales, the earliest researcher into Electricity Long before any knowledge of Electricity existed people were aware of shocks from electric fish. Ancient Egyptian texts dating from 2750 BC referred to these fish as the Thunderer of the Nile, and described them as the protectors of all other fish. Electric fish were again reported millennia later by ancient Greek, Roman and Arabic naturalists and physicians.
- Hozefa Ebrahim, David Ashton-Cleary(Authors)
- 2019(Publication Date)
- Cambridge University Press(Publisher)
Basic Electricity: Voltage, Current and Resistance The word ‘Electricity’ is derived from the Greek word for amber – elektron. This was initially used in the seventeenth century as a result of the Greeks noting that when rods of amber were rubbed against certain materials, they could then be used to attract other substances. This was the first recorded observation of static Electricity. Although this was the initial usage of the word Electricity, the earliest records of electri- city itself actually date back to the Ancient Egyptians, who recorded that certain Nile fish were able to shock wading fishermen. Electricity is a set of physical features that are associ- ated with the presence and flow of charge. The import- ance of Electricity to modern, everyday life is self- evident. Electricity is the movement of electrons through conducting materials of which the most obvi- ous group are metals, e.g. copper and aluminium. Protons, found in the nucleus of atoms, are fixed in position in metals; however, the electrons in these con- ductors are free to move. It is this movement of electrons which gives rise to their conducting properties, essential for Electricity. The SI unit in respect of Electricity is the ampere. This defines electrical current: the flow of elec- tric charge from one point to another. Electrical current is directly analogous to current in a fluid, the water molecules in a river equating to electrons in a copper wire. The faster the flow of water, the stronger the current. Similarly, the faster the movement of electrons down the wire, the higher the electrical current. This can be measured with a galvanometer. A galvanometer is any instrument which transduces current into a mech- anical movement, the most common application being the ammeter, which is used to quantify current. Other applications of galvanometers include steering mechan- isms for lasers, e.g.
eBook - PDF- G. G. Járos, B. J. Meyer(Authors)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
SECTION II Electricity This page intentionally left blank CHAPTER 4 The Origin of Electricity and the Flow of Electricity in Conductors Introduction Despite the fact that Electricity is used daily in all spheres of life, and that its fundamental principles are relatively simple, many people think of it as something mysterious. The study of Electricity deals mainly with the study of the behaviour of charged particles. The problem arises from the fact that man has no sense organ with which he can perceive charged particles. He can only sense the effects of their flow, as for example, when he puts his fingers into a wall plug, or turns on a light switch, or places the two poles of a battery on his tongue. In the first instance, his muscles will contract painfully, in the second, he will perceive light, while in the third instance he will experience an acid taste on his tongue. Until relatively recently we were unable to see viruses, but were nevertheless aware of their existence and of their effects on tissues, including the tissues of the human body. According to the symptoms and signs of diseases produced by viruses, certain properties of these viruses could be inferred. Today we have advanced in the technical field to such an extent that we are able to see viruses by means of very strong microscopes (incidentally microscopes that are based on the principles of Electricity). What is more, the viruses appear pre-cisely as was predicted from their properties. What applied to viruses, holds for Electricity today: we cannot see the structural units of Electricity, even with the most sensitive microscope, but we can infer certain details about them from their behaviour. Atoms and molecules All substances existing in nature can be divided into elements and compounds. There are over a hundred known elements. Each of these is represented by a symbol, e.g., hydrogen by H, oxygen by O, iron by Fe, etc. Compounds are formed by the chemical reaction between two or more elements.
eBook - PDFThe Electronics Companion
Devices and Circuits for Physicists and Engineers, 2nd Edition
- Anthony C. Fischer-Cripps(Author)
- 2014(Publication Date)
- CRC Press(Publisher)
1 Electricity 1 1. Electricity 1. Electricity Summary 2 2 1 d q q k F E q F 1 A Q k E 4 Force between two charges where Force on a charge in a field Electric field - point charge o 4 1 k 2 ˆ r r q k E EA ) ( ) ( 2 2 2 1 1 1 v n q v n q A I dt dq i Ed q W V 1 Electric field - point charge Electric flux Electric current Electric potential R I V R I VI P 2 A R l d A V Q C o l 2 o N A L 2 2 1 CV U 2 2 1 LI U 2 1 2 1 2 1 1 1 1 R R R R R R R R AB AB 2 1 R R R AB Ohm's law Power - resistor Resistivity Capacitance Inductance Energy - capacitor Energy - inductor Resistors - series Resistors - parallel 2 1 1.1 Electricity The Electronics Companion 2 Consider a circuit in which a battery is connected to a light bulb through a switch. Light & heat energy + Chemical energy Switch In this simple electrical system, chemical energy is converted into electrical energy in the battery. The electrical energy travels along the wires to the light bulb where it is converted into heat and light. The switch is used to interrupt the flow of electrical energy to the light bulb. Although such an electrical system may seem commonplace to us now, it Electrical energy was only invented about 100 years ago. For thousands of years before this, light and heat were obtained by burning oil or some other combustible fuel (e.g., wood). Although the concept of electric charge was known to the ancient Greeks, and Electricity as we know it was well-studied in the 19th century, it remained a scientific curiosity for many years until it was put to use in an engineering sense. In the early part of the 20th century, electrical engineering was concerned with motors, generators and generally large scale electrical machines. In the second half of the 20th century, advances in the understanding of the electronic structure of matter led to the emergence of the new field of l t i I iti ll l t i i it b ilt d l ti l l electronics.
eBook - PDF- Kevin Robinson(Author)
- 2020(Publication Date)
- Focal Press(Publisher)
Part I Electrical Theory 2 | Electricity Ke.scy.sc Co.scn.scc.sce.scp.sct.scs.sc i.scn.sc El.sce.scc.sct.scr.sci.scc.sci.sct.scy.sc This chapter introduces a number of key concepts. In so doing it provides a solid framework for the development of an understanding of the behaviour of electronic components and electrical circuits. In keeping with the stated aims of the book to avoid unnecessary levels of detail, the topics discussed here are presented in a relatively broad fashion, with the goal of facilitating a sufficient degree of understanding to guide the practical electronics to come. The technically inclined reader has at their disposal many more rigorous, academic textbooks to choose from if a deeper treatment is sought (see for example Horowitz and Hill, 2015; Sedra and Smith, 2014). The primary goal in this brief chapter is to provide a description of the importance of, and the relationships between, the following key concepts: Electric Charge – positively and negatively charged particles are the basis of Electricity Static and Current Electricity – charge can accumulate (static) or it can flow (current) Current and Circuits – a loop or circuit is generally needed in order for current to flow Direct and Alternating Current – the flow of current can be one way or bidirectional Voltage – the push that causes current to flow (voltage up → current up) Resistance – the opposition to the flow of current (resistance up → current down) Power – when current flows through a circuit work is done, dissipating power Electricity and Magnetism – the two mutually dependant aspects of electromagnetism Conductors and Insulators – materials through which current can and can not flow Electricity deals with the accumulation and movement of charged particles. Two of the key constituents of all matter are positively charged particles called protons, and negatively charged particles called electrons.
eBook - PDF- Richard L. Myers(Author)
- 2005(Publication Date)
- Greenwood(Publisher)
Electricity Introduction Whenever you flip a light switch, start a car, or use an appliance, you deal with some aspect of Electricity. Many of our daily activities use some form of Electricity. It is hard to imagine life in a world without Electricity. Yet, electrical power has only been common in the United States for the past century and still is a luxury in many parts of the world. While we tend to think of Electricity in terms of its practical appli- cations, Electricity also plays a primary role in the physiology of many animals includ- ing humans. Electrical impulses stimulate nerves and relay messages to the brain. Two hundred years ago it was recognized that Electricity and magnetism were related properties that could be unified under a single concept called electromagnetism. Before examining electromagnetism in the next chapter, this chapter will introduce the basic principles of Electricity and some of its applications in our lives. History The phenomenon called Electricity has been observed since the earliest days of humans. Lightning struck fear in our prehistoric ancestors and led to supernatu- ral explanations for the displays accepted today as natural atmospheric occurrences. The ancient Greeks observed that when a tree resin they called elektron hardened into amber, it possessed a special attractive property. When amber was rubbed with fur or hair, it attracted certain small objects. The Greek Thales observed this attrac- tive property and noted the same property existed in certain rocks. Thales' attractive rock was lodestone (magnetite), which is an iron-bearing mineral with natural magnetic properties. The modern study of Electricity commenced with the publication of William Gilbert's (1544-1603) De Magnete in 1600. Gilbert coined the word "Electricity" from the Greek elektron and proposed that the Earth acted as a giant magnet.
- S. B. Lal Seksena, Kaustuv Dasgupta(Authors)
- 2017(Publication Date)
- Cambridge University Press(Publisher)
Prerequisite knowledge Current Electricity of +2 standard Static Electricity of +2 standard 1.1 Introduction The recorded observations related to various electrical events and facts are found dating back to the fifth century BC. The lighting in a stormy night, or the attraction between a rubbed amber and cat’s fur have always provoked human curiosity. But, it was merely a subject of the philosopher’s mind, rather than the business of technology. It was only in the mid-sixteenth century that scientists developed techniques to store electrical charge. Suddenly, like a flash of thunder, everything was changed. We were able to convert a spontaneous event into a continuous operation. The technology had shifted from the era of the mechanical intentions to the era of electrical progression. We can call it a paradigm shift of technology. Like any other paradigm shift, this change did not occur overnight. We have achieved the great electrical inventions through gradual efforts by scientists. Different theories and formulae had made it possible. In this chapter, we are going to discuss these preliminary concepts and related theories to begin with, starting with static electrical charges to laws of current Electricity. We shall also observe that the application of these theories requires a great deal of measurement and quantification of various electrical parameters, such as electrical potential, current flow and resistance. Let us explore this world of Electricity from the perspective of an electrical engineer. 1.2 Charge Electrical charge is the fundamental concept of Electricity. In a mechanical system ‘the matter’ matters, for an electrical system the charge takes all the charges. We conceptualize our materialistic world as an accumulation of particles. In the electrical domain, it is the charge of a particle; we are more concerned about it. Every atom is constituted of a number of charges. There are two types of charges which play major roles in Electricity.
eBook - PDF- James Shipman, Jerry Wilson, Charles Higgins, Bo Lou, James Shipman(Authors)
- 2020(Publication Date)
- Cengage Learning EMEA(Publisher)
Here the towers run through a field of sunflowers. Copyright 2021 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 8.1 Electric Charge, Electric Force, and Electric Field 201 As you will learn in this chapter, electric charge is associated with certain particles that have interacting forces. With a force, there is motion of electric charges (current) as well as electrical energy and power. Understanding these principles makes the benefits of Electricity available to us. Electricity runs motors, heats food, provides lighting, pow- ers our televisions and stereos, and so on. But the electric force is even more basic than “Electricity.” It keeps atoms and molecules—even the ones that make up our bodies—together. It may be said that the electric force holds matter together, whereas the gravitational force (Chapter 3.5) holds our solar system and galaxies together. Closely associated with Electricity is magnetism. In fact, we refer to electromagnetism because these phenomena are basically inseparable. For example, without magnetism, there would be no generation of electrical power. As children (and perhaps as adults), most of us have been fascinated with the properties of small magnets. Have you ever wondered what causes magnets to attract and repel each other? This chapter introduces the basic properties of Electricity and magnetism. Examples of these exciting phenomena are everywhere around us.
eBook - PDFThe Silicon Web
Physics for the Internet Age
- Michael G. Raymer(Author)
- 2009(Publication Date)
- CRC Press(Publisher)
Electronic circuits are at the heart of computers. Each circuit carries out basic operations called logic operations. The opera-tion of such circuits is governed by the principles of Electricity and magnetism. More broadly, the world’s economy and the arts and entertainment industries run primarily on Electricity and magnetism. From lighting in homes and studios to computers used in making music, art, and videos, they are basic to almost every activity. 5.2 ELECTRIC CHARGE The key to understanding Electricity is to learn the basic properties of electric charge — the property of particles that determines electrical forces between them. Charge comes in two types, called positive ( + ) and negative ( − ). These are also called plus and minus . Negative electric charge is inherent in electrons . An electron is an elementary particle that carries a negative electric charge, denoted e . By elementary , we mean that the electron is not made up of any smaller parts, as far as we know. If we consider e to be the unit for charge, then the electron’s charge is equal to −1 e . Let us call the amount of charge on an electron an elementary unit of negative charge . Electrons are tiny, and every common object contains very many elec-trons. For example, the ink making up the period at the end of this sentence contains roughly 10 16 electrons. (The mass of an electron is very small: 0.00000000000000000 000000000000091 kg. In scientific notation, this is 9 1 10 31 . × − k g .) We know that like charges repel each other, and that opposite charges attract; that is, positive charge repels positive charge, negative repels negative, positive attracts negative, and negative attracts positive.
- Mark Z. Jacobson(Author)
- 2020(Publication Date)
- Cambridge University Press(Publisher)
C H A P T E R 4 Electricity Basics A 100 percent wind-water-solar (WWS) energy infra-structure involves electrifying or providing direct heat for all energy sectors and then providing the Electricity or heat with WWS. Because Electricity is such a large part of the solution, understanding how it works is important. In addition, WWS technologies convert either mechan-ical or solar energy into Electricity. This chapter provides the basic information for understanding those conversion processes, which are elaborated on in Chapters 5 (solar energy) and 6 (wind energy). This chapter discusses the basics of Electricity with a particular focus on electric power. It starts by examining different types of electri-city – static Electricity, lightning, and wired Electricity. It then covers voltage and Kirchoff ’ s laws of voltage and current. Next, it turns to power, resistance in series and parallel, and capacitors. This is followed by a discussion of electromagnetism, AC Electricity, and inductors. Both single-phase and three-phase AC Electricity, as well as generators, are then described. Finally, real and reactive power, transformers, and transmission, including high voltage AC and DC transmission, are covered. 4.1 Static Electricity, Lightning, and Wired Electricity Electricity is the free-fl owing movement of charged par-ticles, usually either negatively charged electrons, nega-tively charged ions, or positively charged ions. The fl ow of electric charge constitutes an electric current . The moving charged particles in a current are called charge carriers . Thus, charge carriers can either be electrons, negative ions, or positive ions. Electricity can travel in a wire or another medium, including the air. This chapter discusses primarily electri-city through wires with application to electric power systems. Two other types of Electricity are static Electricity and lightning.
eBook - PDFThe Sciences
An Integrated Approach
- James Trefil, Robert M. Hazen(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
20th Century Fox/The Kobal Collection/Art Resource C H A P T E R 5 Electricity AND MAGNETISM Electric Circuits Most people come into contact with electrical phenomena through electric circuits in their homes and cars. An electric circuit is an unbro- ken path of material that carries Electricity. Such materials are called electrical conductors. Copper wire is an example of a conductor. he luorescent light that you use to read this book, for example, is part of an electric circuit that begins at a power plant that generates Electricity many miles away. hat Electricity continues through power lines into your town and is distributed on overhead or underground wires until it inally gets to where you live. here the circuit, of which the light is a part, is made up of wires that run through the walls of your home. One set of these wires goes irst to a circuit breaker (to break the circuit in case of a dangerous overload of too much current), then to a switch, and inally to the bulb. When you turn on the switch, you complete an unbroken path that runs all the way from the generating plant to the bulb. When Electricity lows through the gas in the luorescent bulb, it excites the atoms and causes them to give of light. When you put the switch in the “of ” position, it’s like raising a drawbridge: the current is blocked from lowing into this part of the circuit, and none reaches the light. he room becomes dark. Every circuit consists of three parts: a source of energy like a battery, a closed path usually made of metal wire through which the current can low, and a device such as a motor or a light- bulb that uses the electrical energy (Figure 5-14). Ohm’s Law One way to think about electric circuits is to draw an analogy between electrons lowing through a wire and water lowing through a pipe. In the case of water, we use two quantities to characterize the low: the amount of water that passes a point each second, and the pressure behind that water.
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