causes of static electricity

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Causes of static electricity

Materials are made of atoms that are normally electrically neutral because they contain equalnumbers of positive charges (protonsin theirnuclei) and negative charges (electronsin "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 materialto the other, which leaves an excess of positive charge on one material, and an equal negative

charge on the other. When the materials are separated they retain this charge imbalance.

Contact-induced charge separation

Triboelectric effect

Electrons can be exchanged between materials on contact; materials with weakly bound electrons

tend to lose them, while materials with sparsely filled outer shells tend to gain them. This isknown as thetriboelectric effectand results in one material becoming positively charged and the

other negatively charged. Thepolarityand strength of the charge on a material once they areseparated depends on their relative positions in thetriboelectric series. The triboelectric effect isthe main cause of static electricity as observed in everyday life, and in common high-school

science demonstrations involving rubbing different materials together (e.g., fur against an acrylic

rod). Contact-induced charge separation causes your hair to stand up and causes "static cling"(for example, a balloon rubbed against the hair becomes negatively charged; when near a wall,

the charged balloon is attracted to positively charged particles in the wall, and can "cling" to it,

appearing to be suspended against gravity).

Pressure-induced charge separation

Main article:Piezoelectric effect

Applied mechanical stress generates a separation of charge in certain types ofcrystalsandceramicsmolecules.

Heat-induced charge separation

Main article:Pyroelectric effect

Heating generates a separation of charge in the atoms or molecules of certain materials. All

pyroelectric materials are also piezoelectric. The atomic or molecular properties of heat and

pressure response are closely related.

Charge-induced charge separation

Main article:Electrostatic induction

A charged object brought close to an electrically neutral object causes a separation of charge

within the neutral object. Charges of the same polarity are repelled and charges of the opposite
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polarity are attracted. As the force due to the interaction of electric charges falls off rapidly with

increasing distance, the effect of the closer (opposite polarity) charges is greater and the twoobjects feel a force of attraction. The effect is most pronounced when the neutral object is an

electrical conductoras the charges are more free to move around. Careful grounding of part of an

object with a charge-inducedcharge separationcan permanently add or remove electrons,

leaving the object with a global, permanent charge. This process is integral to the workings of theVan de Graaf Generator, a device commonly used to demonstrate the effects of static electricity.

Removal and prevention of static electricity

Main articles:Antistatic agentandAntistatic device

Removing or preventing a buildup of static charge can be as simple as opening a window orusing ahumidifierto increase the moisture content of the air, making the atmosphere more

conductive.Air ionizerscan perform the same task.[2]

Items that are particularly sensitive tostatic dischargemay be treated with the application of anantistatic agent, which adds a conducting surface layer that ensures any excess charge is evenlydistributed.Fabric softeners and dryer sheetsused inwashing machinesandclothes dryersare an

example of an antistatic agent used to prevent and removestatic cling.[3]

Manysemiconductor devicesused in electronics are particularly sensitive to static discharge.

Conductiveantistatic bagsare commonly used to protect such components. People who work on

circuits that contain these devices often ground themselves with a conductiveantistatic strap.[4][5]

In the industrial settings such as paint or flour plants as well as in hospitals, antistaticsafety

bootsare sometimes used to prevent a buildup of static charge due to contact with the floor.

These shoes have soles with good conductivity. Anti-static shoes should not be confused withinsulating shoes, which provide exactly the opposite benefitsome protection against serious

electric shocksfrom themains voltage.[6]

Anetwork cardinside anantistatic bag. Anantistatic wrist strapwithcrocodile clip.
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Static discharge

This article needs additionalcitationsforverification. Please helpimprove this articleby

adding citations toreliable sources. Unsourced material may bechallengedandremoved.(September 2010)

Main articles:Electrostatic dischargeandCorona discharge

The spark associated with static electricity is caused by electrostatic discharge, or simply staticdischarge, as excess charge is neutralized by a flow of charges from or to the surroundings.

The feeling of an electric shock is caused by the stimulation of nerves as the neutralizing currentflows through the human body. The energy stored as static electricity on an object varies

depending on the size of the object and itscapacitance, the voltage to which it is charged, and the

dielectric constantof the surrounding medium. For modelling the effect of static discharge on

sensitive electronic devices, a human being is represented as acapacitorof 100picofarads,charged to a voltage of 4000 to 35000 volts. When touching an object this energy is discharged

in less than a microsecond.[7]While the total energy is small, on the order ofmillijoules, it canstill damage sensitive electronic devices. Larger objects will store more energy, which may bedirectly hazardous to human contact or which may give a spark that can ignite flammable gas or

dust.

[edit] Lightning

Natural static discharge

Main article: Lightning

Lightning is a dramatic natural example of static discharge. While the details are unclear and

remain a subject of debate, the initial charge separation is thought to be associated with contact

between ice particles within storm clouds. In general, significant charge accumulations can only

persist in regions of low electrical conductivity (very few charges free to move in thesurroundings), hence the flow of neutralizing charges often results from neutral atoms and

molecules in the air being torn apart to form separate positive and negative charges, which travel

in opposite directions as an electric current, neutralizing the original accumulation of charge. Thestatic charge in air typically breaks down in this way at around 10,000voltsper centimeter (10

kV/cm) depending on humidity. The discharge superheats the surrounding air causing the bright

flash, and produces a shock wave causing the clicking sound. The lightning bolt is simply ascaled up version of the sparks seen in more domestic occurrences of static discharge. The flash
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occurs because the air in the discharge channel is heated to such a high temperature that it emits

light byincandescence. The clap ofthunderis the result of the shock wave created as thesuperheated air expands explosively.

Electronic components

Manysemiconductor devicesused in electronics are very sensitive to the presence of static

electricity and can be damaged by a static discharge. The use of anantistatic strapis mandatoryfor researchers manipulating nanodevices. Further precautions can be taken by taking off shoes

with thick rubber soles and permanently staying with a metallic ground.

Static build-up in flowing flammable and ignitable materials

Discharge of static electricity can create severe hazards in those industries dealing with

flammable substances, where a small electrical spark may ignite explosive mixtures.[9]

The flowing movement of finely powdered substances or low conductivity fluids in pipes orthrough mechanical agitation can build up static electricity.

[10]Dust clouds of finely powdered

substances can become combustible or explosive. When there is a static discharge in a dust or

vapor cloud, explosions have occurred. Among the major industrial incidents that have occurred

are: agrain siloin southwest France, a paint plant in Thailand, a factory makingfiberglass

moldings in Canada, a storage tank explosion inGlenpool, Oklahoma in 2003, and a portabletank filling operation and a tank farm inDes Moines, Iowa andValley Center, Kansasin

2007.[11][12][13]

The ability of a fluid to retain an electrostatic charge depends on its electrical conductivity.

When low conductivity fluids flow through pipelines or are mechanically agitated, contact-

induced charge separation calledflow electrification occurs.[14]

Fluids that have low electricalconductivity (below 50picosiemensper meter), are called accumulators. Fluids having

conductivities above 50 pS/m are called non-accumulators. In non-accumulators, charges

recombine as fast as they are separated and hence electrostatic charge accumulation is notsignificant. In the petrochemical industry, 50 pS/m is the recommended minimum value ofelectrical conductivity for adequate removal of charge from a fluid.

Kerosines may have conductivity ranging from less than 1 picosiemens per meter to 20 pS/m.

For comparison, deionized water has a conductivity of about 10,000,000 pS/m or 10 S/m.[15]

Transformer oilis part of the electrical insulation system of large powertransformersand other

electrical apparatus. Re-filling of large apparatus requires precautions against electrostaticcharging of the fluid, which may damage sensitive transformer insulation.

An important concept for insulating fluids is the static relaxation time. This is similar to the time

constant (tau) within anRC circuit. For insulating materials, it is the ratio of the staticdielectric

constantdivided by the electrical conductivity of the material. For hydrocarbon fluids, this issometimes approximated by dividing the number 18 by the electrical conductivity of the fluid.

Thus a fluid that has an electrical conductivity of 1 pS/m has an estimated relaxation time of
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about 18 seconds. The excess charge in a fluid dissipates almost completely after four to five

times the relaxation time, or 90 seconds for the fluid in the above example.

Charge generation increases at higher fluid velocities and larger pipe diameters, becoming quite

significant in pipes 8 inches (200 mm) or larger. Static charge generation in these systems is best

controlled by limiting fluid velocity. The British standard BS PD CLC/TR 50404:2003 (formerlyBS-5958-Part 2) Code of Practice for Control of Undesirable Static Electricity prescribes pipe

flow velocity limits. Because water content has a large impact on the fluids dielectric constant,the recommended velocity for hydrocarbon fluids containing water should be limited to 1 meter

per second.

Bonding and earthing are the usual ways charge buildup can be prevented. For fluids with

electrical conductivity below 10 pS/m, bonding and earthing are not adequate for charge

dissipation, and anti-static additives may be required

Fueling Operations

The flowing movement of flammable liquids like gasoline inside a pipe can build up static

electricity. Non-polar liquids such asparaffin,gasoline,toluene,xylene,diesel,keroseneand

light crude oilsexhibit significant ability for charge accumulation and charge retention duringhigh velocity flow. Static electricity can discharge into afuelvapor.[16]When the electrostatic

discharge energy is high enough, it can ignite a fuel vapor and air mixture. Different fuels havedifferentflammable limitsand require different levels of electrostatic discharge energy to ignite.

Electrostatic discharge while fueling with gasoline is a present danger atgas stations. Fires have

also been started at airports while refuelingaircraftwith kerosene. New grounding technologies,the use of conducting materials, and the addition of anti-static additives help to prevent or safely

dissipate the build up of static electricity.

The flowing movement of gases in pipes alone creates little, if any, static electricity.[17]It is

envisaged that a charge generation mechanism only occurs when solid particles or liquid droplets

are carried in the gas stream.

Static discharge in space exploration

Due to the extremely low humidity in extraterrestrial environments, very large static charges canaccumulate, causing a major hazard for the complex electronics used in space exploration

vehicles. Static electricity is thought to be a particular hazard for astronauts onplanned missions

tothe MoonandMars. Walking over the extremely dry terrain could cause them to accumulate asignificant amount of charge; reaching out to open the airlock on their return could cause a largestatic discharge, potentially damaging sensitive electronics.[18]
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Ozone cracking

Ozone cracking innatural rubbertubing

A static discharge in the presence of air or oxygen can createozone. Ozone can attack rubberparts. Manyelastomersare sensitive toozone cracking. Exposure to ozone creates deep

penetrative cracks in critical components likegasketsandO-rings.Fuel linesare also susceptible

to the problem unless preventative action is taken. Preventative measures include adding anti-

ozonants to the rubber mix, or using an ozone-resistant elastomer. Fires from cracked fuel lineshave been a problem on vehicles, especially in the engine compartments where ozone can be

produced by electrical equipment.

Energies involved

The energy released in a static electricity discharge may vary over a wide range. The energy in

joules can be calculated from thecapacitance(C) of the object and the static potential Vin volts(V) by the formulaE= CV

2.[19]One experimenter estimates the capacitance of the human body

as high as 400picofarads, and a charge of 50,000 volts, discharged e.g. during touching a

charged car, creating a spark with energy of 500 millijoules.[20]

Another estimate is 100300 pF

and 20,000 volts, producing a maximum energy of 60 mJ.[21]

IEC 479-2:1987 states that a

discharge with energy greater than 5000 mJ is a direct serious risk to human health. IEC 60065states that consumer products cannot discharge more than 350 mJ into a person.

The maximum potential is limited to about 3540 kV, due tocorona dischargedissipating the

charge at higher potentials. Potentials below 3000 volts are not typically detectable by humans.Maximum potential commonly achieved on human body range between 1 and 10 kV, though inoptimal conditions as high as 2025 kV can be reached. Low relative humidity increases the

charge buildup; walking 20 feet (6.1 m) on vinyl floor at 15% relative humidity causes buildup

of voltage up to 12 kilovolts, while at 80% humidity the voltage is only 1.5 kV.[22][23]

As little as 0.2 millijoules may present an ignition hazard; such low spark energy is often below

the threshold of human visual and auditory perception.

Typical ignition energies are:

0.017 mJ forhydrogen

0.2-2 mJ forhydrocarbonvapors

150 mJ for fine flammable dust

401000 mJ for coarse flammable dust
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The energy needed to damage most electronic devices[specify] is between 2 and 1000

nanojoules.[24]

A relatively small energy, often as little as 0.22 millijoules, is needed to ignite a flammable

mixture of a fuel and air. For the common industrial hydrocarbon gases and solvents, the

minimum ignition energyrequired for ignition of vapor-air mixture is lowest for the vaporconcentration roughly in the middle between thelower explosive limitand theupper explosive

limit, and rapidly increases as the concentration deviates from this optimum to either side.Aerosols of flammable liquids may be ignited well below theirflash point. Generally, liquid

aerosols with particle sizes below 10 micrometers behave like vapors, particle sizes above 40

micrometers behave more like flammable dusts. Typical minimum flammable concentrations ofaerosols lay between 15 and 50 g/m3. Similarly, presence of foam on the surface of a flammable

liquid significantly increases ignitability. Aerosol of flammable dust can be ignited as well,

resulting in adust explosion; the lower explosive limit usually lies between 50 and 1000 g/m3;

finer dusts tend to be more explosive and requiring less spark energy to set off. Simultaneouspresence of flammable vapors and flammable dust can significantly decrease the ignition energy;

a mere 1 vol.% of propane in air can reduce the required ignition energy of dust by 100 times.Higher than normal oxygen content in atmosphere also significantly lowers the ignitionenergy.[25]

There are five types ofelectrical discharges:

Spark, responsible for the majority of industrial fires and explosions where static

electricity is involved. Sparks occur between objects at different electric potentials. Goodgrounding of all parts of the equipment and precautions against charge buildups on

equipment and personnel are used as prevention measures.

Brush dischargeoccurs from a nonconductive charged surface or highly charged

nonconductive liquids. The energy is limited to roughly 4 millijoules. To be hazardous,the voltage involved must be above about 20 kilovolts, the surface polarity is negative,

flammable atmosphere is present at the point of discharge, and the discharge energy is

sufficient for ignition. Due to maximum charge density on surface, an area of at least100 cm2 has to be involved. Not observed as a hazard for dust clouds.

Propagating brush discharge is high in energy and dangerous. Occurs when an

insulating surface of up to 8 mm thick (e.g. a teflon or glass lining of a grounded metalpipe or a reactor) is subjected to a large charge buildup between the opposite surfaces,

acting as a large-area capacitor.

Cone discharge, also called bulking brush discharge, occurs over surfaces of charged

powders with resistivity above 1010

ohms, or also deep through the powder mass. Conedischarges aren't usually observed in dust volumes below 1 m3. The energy involved

depends on the grain size of the powder and the charge magnitude, and can reach up to 20

mJ. Larger dust volumes produce higher energies.

Corona discharge, considered non-hazardous

Applications of static electricity
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Static electricity is commonly used inxerography,air filters(particularlyelectrostatic

precipitators), automotive paints, photocopiers,paint sprayers, theaters, flooring in operatingtheaters, powder testing, printers, static bonding and aircraft refueling.

Simple static electricity experiments

Static electricity is notable as a physical phenomenon that can be demonstrated using simple

experiments that can convey genuine understanding of the physics involved.[26]

Charged adhesive tape

Repulsion between lengths of tape with like charges

Attraction between lengths of tape with opposite charges

A simple and illuminating example of the effects of static electricity can be observed using

adhesive tape, charged by peeling. For example,Scotch tapeis on the negative side of the

triboelectric series, hence tends to gain electrons and acquire negative charge.[27]

If a length of tape adhered to a smooth surface is rapidly peeled off, the tape acquires an excess

negative charge (generallypolypropylenewith anacrylicadhesive.)[28][dead link] Do this with two

lengths of tape and they repel each other, which demonstrates that like charges repel. Each

individual length of tape is at least slightly attracted to almost any object, as the presence of the

excess negative chargeinduces a charge separationin nearby objects. Negative charges are

pushed farther away, while positive charges are attracted, and the strength of the attractive andrepulsiveforcesfalls offquite rapidly with distance. This effect is most pronounced in materials
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such asmetals, thatconduct electricity, as the negative charges are free to move within the

material.

Finally, try attaching two lengths of tape together, exhaling on them along the entire length to

neutralize the charge, then rapidly pulling them apart. There will be some imbalance in the

distribution of negative charge between the two pieces such that one is more positive and theother more negative; you should now find that the two lengths of tape attract each other,

demonstrating the fact that opposite charges attract. Attaching the adhesive side of one lengthof tape to the non-adhesive side of the other reduces the chance of tearing and increases the

charge imbalance, and hence the strength of the attractive force.

Static Electricity, the Silent Computer KillerComputer not booting, power light come on, fans are whirring themonitor on/off light turns from green to orange and signal not foundappears and yet the computer fails to respond!The chances are you have a build up of static electricity.All of us are familiar with walking across a rug, reaching out totouch a doorknob, and getting zapped by a charge of static electricity, what's technicallyknown as electrostatic discharge, or ESD. For most of us, it's annoying; for some,dangerous (fireworks and explosive makers have to take special precautions to avoidstatic sparks); and for the sensitive electronics inside a PC, static can be acomputerkiller.A little background: Static electricity is much more common than you might think, andmost of it is created by a process called triboelectrification, when two materials touch(your fingers and your PC keyboard, for example) and then move apart or rub. Electronsare exchanged, and one object becomes electrically positive; the other electricallynegative. When you touch another object with an opposite charge, or a ground (neutralcharge), electrons flow.Every time you plug a device into any computer system, static electricity can easily betransferred from any external device like the following examples.Digital cameras, I pods, Mobile phones, mice, keyboards, flash memory sticks, externalhard drives, speakers, network cables and the list goes on and on, basically if you needto plug it in, it can potentially cause damage.Low humidity in the computers environment helps the computer to build up staticelectricity. Central heating in homes is a major contributor of low humidity in the wintermonths as is air conditioning in the summer months.The average person can carry up to 25,000 volts of static charge at any given time. Thissounds like a lot, but because the current level is low, you usually won't notice it. Justbecause you touched the dog's nose and he didn't yelp, it doesn't mean you are safefrom ESD.Special care needs to be taken when working inside the computer system, to isolate
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static discharge. Wrist bands can be purchased that will give you a ground point, todischarge static as it builds up while working on the insides of a computer system. Antistatic mats can be purchased to stand the computer on and any tools that you areusing.Just putting your screwdriver down onto a worktop can cause static build up, which is

then passed into the computer system.To help keep static to a minimum, keep the computer off any carpets and rugs, alwaystell the computer that you are removing a USB device before pulling it out, keep thecomputer out of the cold and maintain humidity (Humidifiers are appropriate for thiswhere theres a lot of computers). Never work inside the computer without shielding yourself first. Please note: warranties will be voided by most companies if side panelsremoved on computer system. Keep it safe and let the experts fit your hardwaredevices, cheaper than buying a new computer at the end of the day.

Theoretical backgroundCavity QED induced photoelectric effect

Static electricity by the cavity QED induced photoelectric effect occurs by the

Two-step model that comprises contact and separation as illustrated in Fig.

1 (a) and (b), respectively.

Fig. 1 Static electricity: Two-step model(a)Contact (b) Separation

Fig. 1(a) shows rubbing contact produces clusters of atoms of Materials 1 and 2.

Each atom in the clusters contains low frequency IR radiation of magnitude


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3 x kT, the average energy of which may be represented by a harmonic oscillator

with a broad range of frequencies. The instant of separation is depicted in Fig. 1(b).

Briefly, the gap is a high frequency QED cavity, and therefore the low frequency

IR emission from each atom in the clusters is suppressed, a condition referred to as

inhibited cavity QED. To conserve energy, the inhibited IR energy is promptly

absorbed and accumulates to VUV levels in the atoms of the material surfaces

forming the gap.

Electrons are not liberated by the photoelectric effect unless the Planck energy of

the IR radiation accumulates to the threshold given by the work function of the

materials. If the materials have different work functions, the one with the lower

work function is the first to liberate electrons and acquire a positive charge, a

condition consistent with the proposal [4] that the material in the tribolectric series

with the lower work function charges positive and the material with a higher work

function charges negative. Fig. 1(b) depicts Material 2 having a work functionlower than Material 1. Hence, VUV radiation is shown liberating electrons from

Material 2, the electrons donated to Material 1. Material 2 acquires positive charge

and Material 1 negative charge.

Static electricity observed in the rubbing of materials, the rubbing comprising a

repetitive sequence of the gap between rubbed surfaces undergoing contact

and separation is proposed similar to a bubble collapsing and nucleating during

ultrasonic vibration in water. The IR radiation from suspended atoms and

molecules in both the gap and bubble inhibited by the respective high resonant

frequency QED cavities. Nucleation and collapse of bubbles in water is

discussed in Appendix A.

Inhibited IR Radiation And Accumulated IR Energy

The IR radiation inhibited in the cavity QED induced photoelectric effect

accumulates to VUV levels as clusters break away from surface of the rubbed

materials. Both attached and free clusters are illustrated in Fig. 2.


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Fig. 2 Cavity QED induced photoelectric effect - Inhibited IR radiation

Before separation, the attached cluster to the surface of Material 1 emits

uninhibited IR radiation, the wavelength of which exceeds the size of the gap gbetween the surfaces of the materials, i.e., >> g. However, at the instant ofseparating from the surface, the IR radiation from atoms in the free cluster is

suppressed by cavity QED, the wavelength constrained within the confines of thegap g. Assuming a spherical cluster of radiusRo, the inhibited IR energy

UIRis,

where, is the IR energy density, ~Ndofx kT/ 3, kis Boltzmanns

constant, Tis absolute temperature,Ndofis the number of degrees of freedom of

the atoms or molecules in the cluster, and is the solid density spacing between

atoms or molecules in the cluster, ~ 0.3 nm.

The momentary suppression of IR radiation from atoms and molecules within the

clusters is a loss of EM energy. But energy conservation requires thesuppressed EM energy be promptly released to the surrounding space, the energy

release taking the form of multi-IR photons that collectively combine to

VUV levels. In Fig. 2, the cluster rubbed from Material 1 is shown to move into

the evacuated space between the surfaces, the Planck energyEof the EM

radiation at a distanceR from the center of the cluster acting over the adjacent

rubbed surfaces comprised ofmolecules of dimension is,


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where,R ~ g/2. The optical band-gap of Material 2 is assumed less than that of

Material 1, and therefore the Material 1 is depicted in Fig. 2 to lose electrons

and acquire positive charge while Material 2 gains electrons and acquires negative

charge.

Photoelectric yield

In the cavity QED induced photoelectric effect, the numberNe of electrons

produced depends on the numberNp of photons and the photoelectric yield P of

electrons per photon,

Since the released EM radiation is coherent and comprised of multi-IR photons, the

numberNp of VUV photons having Planck energyEVUV may be written,

Most metals illuminated with visible and ultraviolet [9] light have low electron

yields ( P < 10-3 ) while reasonable yields ( P < 10-1) are only obtainedwith VUV light. Generally, the inhibited IR accumulates to VUV levels and so the

photoelectric yield is taken as, P < 0.1.Fig. 3 shows the numberNe of electron charges produced by a single cluster with

the multi-IR photons combining to a Planck energyEVUV~ 4.9 eV. The

radiusR0 is limited to 5 m because if the evacuated space of thicknessD is

treated as a 1D QED cavity, the EM resonant wavelength is, ~ 2D. Tosuppress most of the EM energy, Fig. A-1 shows < 20 m, and thereforeD < 10

m, or the largest cluster that can fit in the 1D space has a radiusR0 < 5m. Hence, static electricity by the cavity QED induced photoelectric effect may

be upper bound by a 5 m radius cluster. Taking a yield P < 0.1, the

electronic charge eNe ~ 3 nC.


14/14

Discovery Bay, Hong KongAbstract. Static electricity is generally thought produced during contact by electrons rubbed from one material bythe other, the rubbing described by the gap between the materials

undergoing a repetitive sequence of contact and separation. But the binding energy of electrons to atoms is far

greater than the van der Walls energy that binds the atoms to each other.Thus, contact during rubbing is likely to produce clusters of atoms from the surfaces of the materials rather than

separating electrons from atoms, the consequences of which lead to a new

explanation of static electricitythe cavity quantum electrodynamics (QED) induced photoelectric effect. During

contact, every atom in the clusters emits uninhibited infrared (IR)

radiation of magnitude 3/2 kT. But separation forms a gap that briefly may be considered a high frequency 1D

cavity, and therefore the low frequency IR radiation from atoms in those

clusters freely suspended in the gap is inhibited by cavity QED. Inhibited IR radiation from the clusters is energy

loss within the gap that is promptly conserved by a gain in IR radiation

absorbed by the atoms on the gap surfaces, the collective IR energy from all atoms in the clusters accumulating in

the surface atoms to vacuum ultraviolet (VUV) levels. Electrons are

produced from the VUV radiation by the photoelectric effect, the materials that lose and gain electrons acquiring

positive and negative charge, respectively.

causes of static electricity

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