Physics
Static Electricity
Static electricity is the build-up of electric charge on the surface of an object. It occurs when certain materials are rubbed together, causing electrons to be transferred from one material to the other. This imbalance of electric charge creates an electric field and can result in sparks or the attraction of small objects.
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10 Key excerpts on "Static Electricity"
No longer available |Learn more- (Author)
- 2014(Publication Date)
- Academic Studio(Publisher)
________________________ WORLD TECHNOLOGIES ________________________ Chapter 5 Static Electricity Lightning over Oradea in Romania ________________________ WORLD TECHNOLOGIES ________________________ Contact with the slide has left her hair positively charged so that the individual hairs repel one another. The hair may also be attracted to the negatively charged slide surface. Static Electricity refers to the build up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static Electricity can be contrasted with current (or dynamic) electricity, which can be delivered through wires as a power source. Although charge exchange can happen whenever any two surfaces come into contact and separate, a static charge only remains when at least one of the surfaces has a high resistance to electrical flow (an electrical insulator). The effects of Static Electricity are familiar to most people because we can feel, hear, and even see the spark as the excess charge is neutralized when brought close to a large electrical conductor (for example, a path to ground), or a region with an excess charge of the opposite polarity (positive or negative). The familiar phenomenon of a static 'shock' is caused by the neutralization of charge. ________________________ WORLD TECHNOLOGIES ________________________ Causes of Static Electricity The materials we observe and interact with are formed from atoms and molecules that are electrically neutral, having an equal number of positive charges (protons in the nucleus) and negative charges (electrons in shells surrounding the nucleus). The phenomenon of Static Electricity requires a separation of positive and negative charges. When two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other.
eBook - PDF- Michael Neidle(Author)
- 2016(Publication Date)
- Butterworth-Heinemann(Publisher)
Chapter 3 Static Electricity Static Electricity refers to electricity 'at rest' on an insulator in contrast to current electricity where the electrons are in continuous movement through a conductor. A common effect of Static Electricity occurs when a portion of insulation being stripped from a p.v.c.-insulated cable flies off and clings to a wall. If a fountain pen is rubbed, it is found to pick up small pieces of light materials such as paper, etc. During dry cold winters, office workers walking on nylon carpets have been known to feel a prickle and even see sparks coming from their fingers when approaching hot-water radiators. These are all simple examples of electric charges that have been built up. An understanding of them helps to explain electrical applications of great practical importance. 3.1. Charges The atoms which comprise all matter, i.e. everything which occu-pies space, are ultimately electrical in nature. The simple hydrogen atom indicates the general pattern. The inner core or nucleus contains the positively-charged proton ; orbiting round the nucleus is the single negatively-charged electron. Unimaginably small as is the atom—smaller than 10^ millimetres in diameter—its structure contains the neutron, which possesses no charge, and many other sub-atomic particles. Fortunately, most of our electrical theory can be explained in terms of the proton and electron parts of the atom alone. Normal materials, such as the book you are reading, are electric-ally neutral, i.e., they show no external electricity because the proton and electron charges exactly balance or cancel each other out. An atom is positively charged when electrons are lost and negatively charged when an atom possesses surplus electrons. Sometimes the process is known as ionisation. Atoms which are deficient in electrons are called positive ions and those which have gained electrons, negative ions.
eBook - PDF- Michael Neidle(Author)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
Chapter 3 Static Electricity Static Electricity refers to electricity 4 at rest' on an insulator in contrast to current electricity where the electrons are in continuous movement through a conductor. A common effect of Static Electricity occurs when a portion of insulation being stripped from a p.v.c.-insulated cable flies off and clings to a wall. If a fountain pen is rubbed, it is found to pick up small pieces of light materials such as paper, etc. During dry cold winters, office workers walking on nylon carpets have been known to feel a prickle and even see sparks coming from their fingers when approaching hot-water radiators. These are all simple examples of electric charges that have been built up. An understanding of them helps to explain electrical applications of great practical importance. 3.1. Charges The atoms which comprise all matter, i.e. everything which occu-pies space, are ultimately electrical in nature. The simple hydrogen atom indicates the general pattern. The inner core or nucleus contains the positively-charged proton ; orbiting round the nucleus is the single negatively-charged electron. Unimaginably small as is the atom—smaller than 10 6 millimetres in diameter—its structure contains the neutron, which possesses no charge, and many other sub-atomic particles. Fortunately, most of our electrical theory can be explained in terms of the proton and electron parts of the atom alone. Normal materials, such as the book you are reading, are electric-ally neutral, i.e., they show no external electricity because the proton and electron charges exactly balance or cancel each other out. An atom is positively charged when electrons are lost and negatively charged when an atom possesses surplus electrons. Sometimes the process is known as ionisation. Atoms which are deficient in electrons are called positive ions and those which have gained electrons, negative ions.
eBook - ePub- Christopher Nordstrom, George Rendel, Luke Baxter(Authors)
- 2016(Publication Date)
- CRC Press(Publisher)
Physics 1. Electricity 1.1 ElectrostaticsA material may be an electrical conductor, in which case it will easily disperse any electrical charge that it gathers. Other materials may be electrical insulators that do not disperse charge easily.If an insulator is rubbed it may become positively charged by losing electrons, or it may become negatively charged by gaining electrons. Friction causes the displacement of electrons.For instance, an acetate rod that is rubbed with a duster will lose electrons to the duster and become positively charged. A polythene rod that is rubbed with a duster will acquire electrons and become negatively charged (the duster will be positively charged).Charged objects with the same charge will be repelled from each other. Objects with different charges will be attracted to each other.Static Electricity is useful in some cases in industry, e.g. it can be used in spray painting. The object that needs to be painted is given a particular charge, and the paint droplets are given the opposite charge as they are released. This means the paint is attracted to the object and less is wasted.Static Electricity also poses a danger in some cases. Build-ups of charge may eventually be dissipated in the form of a spark. In certain scenarios, such a spark may ignite a fire. Hence certain precautions need to be taken, for instance, with vehicles that are used to transport flammable substances. Any charge that is built up as the vehicle travels needs to be discharged using an earth wire – this reduces the chance of a spark igniting a fire.1.2 Electric currentCurrent (I) is the flow of charge (usually electrons, although currents can be carried by other charged particles such as ions) through an electrical conductor. Its unit is the ampere (A)
eBook - PDF- Danuta Koradecka(Author)
- 2010(Publication Date)
- CRC Press(Publisher)
219 10 Static Electricity Zygmunt J. Grabarczyk 10.1 INTRODUCTION Static Electricity is the formation, accumulation, and disappearance of an unbal-anced electric charge Q . The unbalanced charge is usually formed on the surface of solid or liquid objects, which can be compact or broken up (e.g. dust and haze particles), of low electrical conductivity (dielectrics, semiconductors), and can con-duct objects insulated from the ground. Also, the external electric field induces the electric charge on the surface of conducting object. In the electrified object, there is at least a local lack of equilibrium between the number of elementary positive and negative charges. Gas particles can be electrified or ionised only by ionising radiation or electrical discharges. Gases (e.g. atmospheric air) carry aerosol particles, such as dust, smoke, ice crystals, or haze electrified by other mechanisms. The change in the charge is equivalent to the electric current flow. The intensity of the electric current flow is proportional to the speed of the charge change. The current pulse intensity during the electrostatic discharge (ESD) may be up to a few dozen amperes. The separation of positive and negative charges requires working against the coulomb (C) force. This work is converted into the potential energy of the electric field. When the unbalanced charge disappears, the energy of the field is converted into other forms, such as thermal (above 90% of the local energy), mechanical (e.g. acoustic), and electromagnetic (Gajewski 1987). The unbalanced charge can decay slowly and continuously (taking from millisec-onds to many hours and according to an exponential dependence on time) or rapidly (from tens of nanoseconds to a few hundred microseconds). In the first case, the neu-tralisation of excess charge via the conduction of a material is called the dissipation CONTENTS 10.1 Introduction ..................................................................................................
eBook - ePub- Samarendra Kumar Biswas, Umesh Mathur, Swapan Kumar Hazra(Authors)
- 2021(Publication Date)
- CRC Press(Publisher)
The process of electrification (e.g., by rubbing glass with silk) is caused by the movement of electrons. In an uncharged body, atoms are electrically neutral, i.e., the total negative charge on the electrons is equal to the total positive charge on the atomic nuclei. Electrons are free to move, for example, during rubbing or when a body is placed in an electric field. An excess of electrons in a body, relative to its neutral state, means that the body is negatively charged. Similarly, a deficit of electrons relative to a neutral state means that the body is positively charged. The magnitude of the charge is expressed in coulombs (C).When the properties of flowing (current) electricity were discovered, the term static came into use to distinguish an electric charge that was at rest from one that was in motion. Today the term Static Electricity is used to describe phenomena from an electric charge, regardless of whether the charge is at rest or in motion.3 Streaming current or charging current (expressed in amperes) is defined as the flow rate of charge into a given system per unit of time. It is the current caused by the rate of flow of charged material into a system; it should be distinguished from the rate of static charge generation within a batch system, such as during the rubbing of solids or stirring of liquids.Static Electricity involves high potentials, generally of the order of kilovolts, and very low currents, generally in the range of milliamperes (mA). Therefore, Static Electricity effects are associated with an electric field, but unlike current electricity, Static Electricity has no significant magnetic field effects.Earth is a near-infinite “reservoir” of electrons and is conventionally referred to as having zero potential. Therefore, if a charged conductor is electrically connected to the earth, its potential becomes zero. Earthing also removes all charge from a conductor unless there is another charged body in its vicinity that influences by induction.Bodies with unlike charges attract each other, and those with like charges repel. Based on Coulomb’s law, if two bodies (that are small compared to the distance between them), having charges Q 1 and Q 2 coulombs, are placed in vacuum at a distance of r (m) between them, then the force F
eBook - PDF- Albert Wang(Author)
- 2021(Publication Date)
- Wiley-IEEE Press(Publisher)
Charge conservation does not prohibit static charges from being generated or destroyed. But any gain in charges somewhere at a time will accompany with the loss of the same amount of charges somewhere else. Static charges are associated with electric charging and discharging for an object. Electric charging puts static charges into an object, while electric dis-charging removes static charges from an object. Electric charging and discharging are two opposite phenomena associated with static charges, which involve separation and neutralization of positive and negative charges of materials. Electric charging leads to Static Electricity. Static charge gen-eration requires separation of positive and negative charges through electric charging procedure. Normally, materials are electrically neutral because the atoms have same number of positive and negative charges. When two objects are in contact, electrons may move in between, which causes imbalance of positive or negative charges within each object. Then, when the two objects are sep-arated thereafter, they may retain the charge imbalance, i.e., containing net positive or negative charges. This completes a charging procedure. Therefore, the Static Electricity phenomena involve contact and separation of materials. There are many electric charging mechanisms. The most com-mon electrostatic charging phenomena observed in our daily life is the triboelectricity phenomena, which follow a contact-induced charge separation mechanism. When two objects with different electrical resistivity are in contact, electrons will exchange in between due to different binding force. Upon separation of the two objects, each object will be electrically charged containing either net positive or negative charges. Many magic and fun Static Electricity phenomena observed in our life follow the contact-induced charge separation procedure.
eBook - PDF- Günter Luttgens, Norman Wilson(Authors)
- 1997(Publication Date)
- Butterworth-Heinemann(Publisher)
Chapter 2 Origin of Static Electricity Man-made current electricity has been in existence now for about a hundred years and its use as a source of power in industry, commerce and in the home is widespread throughout the world. The origins of current electricity are to be found in Static Electricity - a phenomenon, which although known to man for thousands of years, is today still considered to be something of a mystery. A contemporary Englishman has succinctly described it thus: 'Static Electricity is an unpredictable phenomenon, here today and gone the next.' It is probably because of its unpredictability that Static Electricity is often, incorrectly, blamed as the cause of industrial accidents involving fire and explosion when no other plausible explanation can be found. Electricity is a manifestation associated with the fundamental electrical charge to be found within the atom, namely, the electron. A surplus of electrons, which are negative charges, results in a region of negative polarity. A deficiency of electrons signifies positive charges, and a region of positive polarity. In deciding how to approach the subject of charge formation we consider the analogy of someone going on holiday. The person would need to take with him a suitable map, e.g. in the case of a hiker, a map on which the contours and footpaths were shown in detail, and for a motorist, one on which the roads were given prominence. In a way a map can be regarded as a model of the Origin of Static Electricity 15 area to be explored. An analogy in electrostatics could be the exploration of the formation of Static Electricity. Some explorers might be interested in the fundamental quantum mechanics of charge transfer, as is described in the electron energy band model, while others would choose a phenomenological approach. For the practical cases which are dealt with in this book, the latter is considered to be the most useful and is described in the following section.
eBook - ePub- J. W. S. Hearle, W E Morton(Authors)
- 2008(Publication Date)
- Woodhead Publishing(Publisher)
23 Static Electricity 23.1 Introduction Some of the effects of Static Electricity were described by Thales in about 600 BC, and the first understanding of the nature of electricity came from the study of the phenomenon of Static Electricity in the 18th century. After the discovery of current electricity, however, the study of Static Electricity, with all its experimental difficulties, was neglected, but the increasing amount of trouble in industry that is due to static, resulting from the introduction of new materials, particularly synthetic fibres, led to a revived interest in it [ 1 – 3 ]. Holme et al. [ 4 ] have published a more recent review. Through its effects, static causes a variety of troubles in textile materials and processing. Similar charges repel one another. This causes difficulty in handling materials. The filaments in a charged warp will bow out away from one another. There will be ‘ballooning’ of a bundle of slivers. Cloth will not fold down neatly upon itself when it comes off a finishing machine and so on. Unlike charges attract one another. This has caused difficulty in the opening of parachutes. It will also cause two garments, oppositely charged, to stick to one another, and in movement one garment may ride up on the other and cause embarrassment to the wearer. Another consequence is the attraction to a charged material of oppositely charged particles of dirt and dust from the atmosphere (Fig. 23.1). After 15 days, the soiling of a cotton fabric held at + 1.2 kV was over twice as severe as at 0 kV. At –12 kV it was 13 times worse, but at + 12 kV it was 19 times worse owing to the preponderance of negatively charged dirt particles in the atmosphere [ 5 ]. This fine dirt adheres so firmly that it is difficult to remove and causes serious soiling. When this occurs on the portion of cloth in a loom that is left exposed overnight, it is known as ‘fog-marking’
eBook - PDF- Paul Peter Urone, Roger Hinrichs(Authors)
- 2012(Publication Date)
- Openstax(Publisher)
Electric Field 721 xerography: a dry copying process based on electrostatics Section Summary 18.1 Static Electricity and Charge: Conservation of Charge • There are only two types of charge, which we call positive and negative. • Like charges repel, unlike charges attract, and the force between charges decreases with the square of the distance. • The vast majority of positive charge in nature is carried by protons, while the vast majority of negative charge is carried by electrons. • The electric charge of one electron is equal in magnitude and opposite in sign to the charge of one proton. • An ion is an atom or molecule that has nonzero total charge due to having unequal numbers of electrons and protons. • The SI unit for charge is the coulomb (C), with protons and electrons having charges of opposite sign but equal magnitude; the magnitude of this basic charge ∣ q e ∣ is ∣ q e ∣ = 1.60×10 −19 C. • Whenever charge is created or destroyed, equal amounts of positive and negative are involved. • Most often, existing charges are separated from neutral objects to obtain some net charge. • Both positive and negative charges exist in neutral objects and can be separated by rubbing one object with another. For macroscopic objects, negatively charged means an excess of electrons and positively charged means a depletion of electrons. • The law of conservation of charge ensures that whenever a charge is created, an equal charge of the opposite sign is created at the same time. 18.2 Conductors and Insulators • Polarization is the separation of positive and negative charges in a neutral object. • A conductor is a substance that allows charge to flow freely through its atomic structure. • An insulator holds charge within its atomic structure. • Objects with like charges repel each other, while those with unlike charges attract each other. • A conducting object is said to be grounded if it is connected to the Earth through a conductor.
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