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Static Electricity can be defined as an imbalance of electric charges in a body. This imbalance gets created when there is an unequal number of negative and positive charges present in a body.
- An electrically neutral body has an equal number of negative and positive charges.
- When two electrically neutral body is rubbed against each other, the transfer of negative charges or electrons takes place.
- The body which gains the electrons becomes a negatively charged body and the body that loses the electron becomes a positively charged body.
- These developed charges also known as the static electric charge will remain at rest on the surface as static electricity in the body until it is moved away by means of electric current or electric discharge.
- Electrostatic discharge or static shocks (electrostatic shocks) is the sudden flow of electric current between two electrically charged objects when brought in contact.
- On rubbing a balloon on hair, the balloon becomes negatively charged and the hair becomes positively charged. Hence, the hair gets pulled towards the hair.
- This accumulation of charge is called static electricity.
- A lightning strike is a natural phenomenon caused due to static charge accumulation in the clouds.
Read More: NCERT Solutions Chapter 3 Current Electricity
| Table of Content |
Key Terms: Static Electricity, Lightning, Static Charge, Electric Charge, Circuit, Static Electric Generator, Lightning Rod, Lightning Strike, generating static electricity, preventing static electricity
What is Static Electricity?
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The imbalance of electric charges in a body due to the varying number of positive and negative charges is called static electricity.
- The term ‘Static’ is because when electrons are displaced between insulating materials, they tend to stay stationary.
- When a glass rod is rubbed against a synthetic cloth, the glass, and the silk tends to stick together due to the generation of static electricity.
- Physical contact between objects causes the formation of static electricity.
- Electrons are loosely held in the atomic structure and can be displaced by simple actions like rubbing.
- Electron build-up occurs till there is a way to discharge the accumulated electrons.
- A lightning strike is a classic example of static electricity.
- Static charges can be on the surface, imparted by physical contact, or through extra ions present in the air.
- The potential energy of the collection of charges on a body is called electrostatic energy or electrostatic potential energy.
Glass Rod Rubbed against Silk
Discover about the Chapter video:
Current Electricity Detailed Video Explanation:
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Static Electricity Generation
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Static electricity occurs with the movement of electric charges whenever there is physical contact or friction between two bodies.
- An atom consists of positively charged protons, negatively charged electrons, and neutrons.
- If the number of electrons and protons in a body is equal, then the body is said to be electrically neutral.
- Whenever two objects make contact with one another or when there is friction between them, an electron is transferred from one material to another.
- Electrons move from the material with a weaker bond to the material with a stronger bond.
- Due to this movement, the object loses its electrical neutrality, and static electricity is accumulated.
- The electrically neutral object which gains the electrons becomes negatively charged and the neutral object which loses the electrons becomes positively charged.
- Protons are not responsible for the transfer of electric charges because protons and neutrons in the nucleus are bound by nuclear forces which are much stronger than the electrostatic force between electrons and the nucleus.
- The phenomenon in which electric charges are exchanged between the surfaces of two objects that come into contact with each other is called static buildup.
Read More: Current Density
Properties of Static Electricity
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Some of the interesting characteristic properties of static electricity are listed below:
- It is caused by the imbalance in positive and negative charges.
- Static electricity is seen in conductors and insulators.
- Static electricity is most prevalent during the dry season as moisture does not allow the transfer of electrons.
- Continuous electric current is not produced during static electricity.
- Charges produced are static through the forcefield and do not allow energy to get dissipated.
- The difference between static and current electricity is that static electricity is due to the accumulation of electric charges on the surface of a body and current electricity is due to the flow of electric charges.
- Grounding is an effective method for removing static electricity in conductors, such as metals
Examples of Static Electricity
- Rubbing nylon cloth against another fabric or the wearer’s skin causes the formation of static electricity.
- Dust particles in the air get polarised by the television screen and stick due to electrostatic interaction between dust particles and the TV screen.
- Electrostatic force (Static electricity) gets developed during winters between the fabric layer and human skin.
- Some of the use of static electricity are printers and photocopiers where static electric charges attract the ink, or toner, to the paper
- Bits of paper get stuck to the comb brought in contact with it immediately after combing.
- Static electricity accumulated in the clouds is the reason behind the lightning strike.
Read More: Earth Vs Neutral
Static Charge Build-up in the Clouds
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Given below is the formation of charges in the clouds due to static electricity.
- Water from the surface of the earth evaporates and reaches higher levels of the atmosphere.
- Warm droplets from the earth’s surface move upwards and cool water droplets drop down in the form of heavy rain clouds which cause rain.
- The opposing motion of the water droplets causes the transfer of electrons due to friction.
- Electron transfer causes the mixing up of air on the upper layers of the atmosphere.
- The top part of the clouds develops an excessive positive charge and the bottom part develops an equally excessive negative charge.
- The tiny droplets in the sky further freeze causing a greater amount of charge imbalance.
- This causes an overall charge imbalance in the cloud.
Lightning and Lightning Strike
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- Charge irregularity in the cloud due to the buildup of static charges continues to increase.
- Air regularly does not permit the progression of charges through it and thus the unevenness further increases.
- After a specific point, the cloud cannot deal with excessive charge unevenness.
- Charge tension is removed by opening up a channel of conduction.
- This channel is through the air which permits the charges to discharge reducing the tension.
- This channel of conduction is known as lightning.
- Lightning strike causes billions of electrons to escape through this tiny way causing excessive heating up of electric charges and making the path extend fiercely.
- This extension of air makes a boisterous thundering commotion commonly called thunder.
Lightning Strike due to Static Electricity
Also Read: Kirchhoff’s Rules
Protective Measures Against Lightning
- Tall structures, farmhouses, and other construction sites are prone to lightning strikes.
- To prevent this, they are regularly furnished with lightning poles or rods.
- A lightning rod is a pole made of metal that is mounted on the top of the structure and goes into the ground.
- The lightning rods stretch out over the structure, higher than the structure so the bar interacts with the charges first.
- The metal secures the direct exposure to the charges from the cloud away from the structure and into the ground thus protecting the structure from static charge and static electricity generation.
Lightning Rod
Also Read: Winds, Storms & Cyclones
Types of Electric Charges
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Electric charge is the property of a particle due to which it can apply force on other charged or uncharged particles.
There are two types of electric charges: positive charges, and negative charges.
- The electron has a negative charge, while the proton has a positive charge.
- In an electrically neutral material number of protons and electrons are identical.
- The force of attraction or repulsion between two charges is called electrostatic force or electric force.
- Like charges repel each other while unlike charges attract each other.
- The region or space around a charged body within which its influence can be felt by other small charges is called an electrostatic field or electric field.
- The SI Unit of Electric charge is Coulomb.
Positive and Negative Charge formation
Read Also: Physical Significance of Electric Field
Static Electricity Generator
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A static electricity generator is used to produce contact-based power. The friction is converted to electricity by a static electricity generator.
There are two procedures that are used for generating static charges:
- Triboelectric Effect: This occurs when the two objects come closer to each other and the charge gets transferred due to friction.
- Electrostatic Induction: Charging by induction redistributes charges on the surface of an object owing to the nearby charges or static electric field.
Static Electricity Generator
Also Read:
| Important Concepts Related to Current Electricity | ||
|---|---|---|
| AC Generator | Types of Current | Reactance and Impedance |
| Electrical Current | Resistor Colour Codes | Ampere |
| Circuit Diagram | Drift velocity | Unit of Current |
Things to Remember
- The imbalance of charges on an object produces static electricity.
- The excessive charge gets built up due to the increase in positive and negative charges on the top and bottom of the clouds.
- The excessive charges find a way of discharge through the air and thus cause lightning and lightning strikes to occur.
- A static electricity generator uses the mechanism of converting frictional energy into static electricity.
- Charges are classified as positive and negative charges.
- Triboelectric series- A rundown that positions different materials as per their inclination to acquire or lose electrons.
- Electrostatic Induction- Rearranging the charges on the outer layer of an item as a result of the close-by charges or static electric field.
Read Also: Electromotive Force
Previous Year Questions
- If now we hav.e to change the null point at 9th wire, what should we do?… [ DUET 2007 ]
- Find R between A and B...
- Find the current drawn from the battery just after the switch is closed…
- Five dry cells each of e.m.f. 1.5 V and internal resistance 1Ω1Ω are connected in parallel….
- In order that the bridge may be balanced is….
- When two resistances R1 and R2 are connected in series, they consume 12W power….[KEAM]
- Nichrome is used as electrical heating element because of its…[KEAM]
- In the figure shown below, the terminal voltage across E2 is…[KEAM]
- In a potentiometer of wire length ll, a cell of emf V is balanced at a...[KEAM]
- A potentiometer wire AB having length L and resistance 12r is joined to… [JEE Main 2019]
- A resistance is shown in the figure. Its value and tolerance are given respectively by ...[JEE Main 2019]
- The resistance between any two vertices of the triangle is...[JEE Main 2019]
- In the given circuit, an ideal voltmeter connected across the 10Ω resistance...[JEE Main 2019]
- In the experimental set up of metre bridge shown…..[JEE Main 2019]
Sample Questions
Q1. An equivalent plate capacitor, each with plate area A. besides, separation d, is charged to a potential differentiation V. The battery used to charge it stays related. A dielectric piece of thickness d and dielectric predictable k is right now situated between the plates. What change, expecting to be any, will happen in :
(i) charge on plates?
(ii) electric field power between the plates?
(iii) capacitance of the capacitor?
Legitimize your answer for every circumstance. (2010)
Ans: Given: Plate space of either plate or equivalent plate capacitor = A
Distance between the plates = d and
logical differentiation between the plates = V
∴ Initially capacitance, C = ε0Ad,
Charge on the plate, Q = CV
As the battery stays related all through, the normal qualification between the plates stays unaltered (V' = V) on putting a dielectric segment of thickness 'd' and dielectric steady 'k' between the plates.
(i) New charge on plates, Q' = C' V' = kCV = kQ
Thus, the charge changes to k events of its special worth.
(ii) Electric field power between the plates, E'=V'/d=V/d=E
Therefore, the electric field power between the plates of the capacitor stays unaltered.
(iii) New capacitance of the capacitor, C'=ke0A/d=kC
Q2. How is static electricity created? (2 marks)
Ans. Static electric charge can be created by rubbing two surfaces in contact that are at some distance. Moreover, at least one of the surfaces has a high resistance to electric current (and is, therefore, an electrical insulator). So, this is how static current is produced.
Q3. Which bearing of an electric dipole in a uniform electric field would identify with stable amicability? (All India 2008)
Ans:Right when the dipole second vector is compared to the electric field vector
P→ΙΙEΙΙ
Q4. In the unlikely event that the range of the Gaussian surface encasing a charge is parted, how does the electric progress through the Gaussian surface change? (2013)
Ans: Electric movement ΦE is given by
ΦE=Qε0
where [Q] is finished charge inside the shut surface
∴ On changing the scope of the circle, the electric movement through the Gaussian surface leftover parts same.
Q5. Characterize the term electric dipole snapshot of a dipole. Express its S.I. unit (2011)
Ans: τ = OE sin θ
Assuming E = 1 unit, θ = 90°, τ = P
Dipole second might be characterized as the force following up on an electric dipole, set opposite to a uniform electric dipole, set opposite to a uniform electric field of unit strength.
or then again Strength of the electric dipole is called dipole second.
|P→|=q|2a|
∴ SI unit is C-m.
Q6. In which direction, a dipole put in a uniform electric field is in a stable, temperamental balance? (Delhi 2010)
Ans: For stable harmony, a dipole is put corresponding to the electric field.
For unsteady harmony, a dipole is put anti-parallel to the electric field.
Q7. Is the electric field because of an accused design of all-out charge zero, fundamentally zero? Legitimize. (All India 2012)
Ans: No, it isn't really zero. On the off chance that the electric field because of an accused setup of absolute charge is zero in light of the fact that the electric field because of an electric dipole is non-zero.
Q8. What is a device that you can use to maintain a potential difference between the ends of a conductor? Also explain the process by which this device does so. (Board Term I, 2013)
Ans. A cell or a battery can be used in order to maintain a potential difference between the ends of a conductor. The chemical reaction within a cell generates the potential difference across the terminals of the cell, even when no current is drawn from it. When it is connected to a conductor, it produces electric current and, maintain the potential difference across the ends of the conductor.
Q9. What is electric current? (1/5, Board Term 1,2017)
Ans. Electric current can be defined as the amount of charge flowing through a particular area in unit time.
Q10. State the Ohm’s law. (AI 2019)
Ans. Ohm’s law states that the potential difference V, across the ends of a given metallic wire in an electric circuit is directly proportional to the current flowing through it, provided its temperature remains the same. Mathematically,
V ∝ I
V = RI
where R is resistance of the conductor.
Q11. What is static electricity generatot? (3 marks)
Ans. Static electricity can be produced with the use of an electrostatic generator. It generates static electricity by transforming friction into electricity.
There are two methods that are used for producing static charges:
- Triboelectric Effect: If two objects come closer and the charge is transferred between them due to friction is known as the triboelectric effect.
- Electrostatic Induction: It is the process of redistributing the charges on the surface of an object because of the nearby charges or static electric field.
Q12. Write two uses of static electricity. (2 marks)
Ans. The two uses of static electricity are:
- Pollution manage: Static electricity is used in pollutants management by making use of a static fee to dust particles in the air after which collecting those charged particles on a plate or collector of the opposite electriccharge.
- Smokestacks: Factories use static electricity in order to reduce pollutants coming from their smokestacks. They supply the smoke with an electric-powered charge. When it travels by electrodes of the opposite charge, most of the smoke particles cling to the electrodes. This maintains the pollutants from going out into the atmosphere.
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