Static Electricity Class 8 Questions and Answers Notes Basic Science Chapter 10 Kerala Syllabus

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Class 8 Basic Science Chapter 10 Static Electricity Question Answer Notes

Class 8 Basic Science Chapter 10 Notes Kerala Syllabus Static Electricity Question Answer

Static Electricity Class 8 Questions and Answers Notes

Let’s Assess

Question 1.
Assume you are given an object with a positive charge. Write down a suitable method to charge a metal sphere using this.

Object	Charge to be gained	Suitable charging method
Metal sphere	Positive
Metal sphere	Negative

Answer:

Object	Charge to be gained	Suitable charging method
Metal sphere	Positive	Charging by Conduction
Metal sphere	Negative	Charging by Induction

Question 2.
At petrol pumps, the nozzle used for filling petrol is earthed. Why?
Answer:
To prevent sparks and fire.

• Reason: As petrol (a highly flammable liquid) flows quickly through the pipe and nozzle, friction can build up a significant amount of static electricity on both the nozzle and the vehicle.
• If this static charge becomes large enough, it can discharge as a spark to the car’s body.
• A spark in the presence of petrol fumes will cause a dangerous fire or explosion.
• Earthing the nozzle provides a continuous path for any static charge to flow safely into the ground, neutralizing it and preventing any sparks from forming.

Question 3.
A plastic pen can be easily charged by rubbing it on hair. However, this is not possible when a steel spoon is used instead of this. What is the reason?
Answer:
The reason is the difference between insulators and conductors.

• Plastic Pen: Plastic is an insulator). When you rub it, the static charge builds up on its surface and stays there because it cannot flow easily.
• Steel Spoon: Steel is a conductor. Your hand and body are also conductors. When you rub the steel spoon, charges are indeed separated. However, they immediately flow through the spoon, through your hand and body, and safely into the Earth.
• Because the charge cannot accumulate, the spoon remains neutral and doesn’t show any static electric effects.

Question 4.
If a positively charged metal object comes into contact with another negatively charged metal object of equal magnitude, determine the charge on both objects.
Answer:
The charge on both objects will be zero (0). They will become electrically neutral.

When the two objects touch, the excess electrons from the negatively charged object flow to the positively charged object, which has a corresponding deficit of electrons. Since the charges were of equal magnitude, this transfer perfectly balances the charges, resulting in no net charge on either object. This is called neutralization.

Question 5.
Poorly earthed lightning conductors are more harmful than beneficial. What is the reason?
Answer:
A lightning conductor is designed to attract a lightning strike by using induction at its sharp point. Its only job is to provide a safe, low-resistance path for the massive electrical charge to go directly into the Earth.

• If it is “poorly earthed” (meaning the connection to the ground is broken, loose, or not deep enough), it will still attract the lightning strike.
• However, the charge will not have a safe path to the ground. Instead, the lightning will find the next easiest path, which will be the building itself (through its metal pipes, wiring, or concrete).
• This will cause a massive surge of electricity through the building, leading to major fires, explosions, and destruction. A poorly earthed rod essentially invites the lightning to strike the building and provides no protection.

Basic Science Class 8 Chapter 10 Question Answer Kerala Syllabus

Textbook Page No : 167 & 168

Question 1.
How might the teacher have resolved the children’s doubt (about anti-static gloves)?
Answer:
The teacher would explain that the anti-static gloves are used to avoid static electricity. They prevent the static charge that accumulates on a person (e.g., from clothes rubbing) from transferring to and damaging sensitive electronic components inside devices like mobile phones.

Question 2.
Can you see the hairs being attracted to the balloon?
Answer:
Yes, the hairs are attracted to the balloon.

Question 3.
What do you observe? (Plastic pen near paper before rubbing)
Answer:
There is no observable attraction.

Question 4.
What difference do you notice? (Plastic pen near paper after rubbing)
Answer:
The pen now attracts the piece of paper.

Question 5.
Is there any change for the water stream? (Plastic scale near water before rubbing)
Answer:
No, there is no change for the water stream

Question 6.
What do you observe? (Plastic scale near water after rubbing)
Answer:
The water stream is attracted to and deflected towards the rubbed plastic scale.

Question 7.
What can you infer from the activities done so far?
Answer:
Rubbed objects gain a charge and thus gain the ability to attract other objects.

Question 8.
Table 10.1 Completion (Attracts small pieces of paper / Doesn’t attract (X))

Answer:

Question 9.
Do all objects gain the ability to attract when rubbed?
Answer:
No. Only some pairs of objects gain this ability when rubbed against each other.

Textbook Page No : 169 & 170

Question 10.
What are the main particles in an atom?
Answer:
Protons, Neutrons, and Electrons.

Question 11.
What are the main particles in the nucleus?
Answer:
Protons and Neutrons.

Question 12.
What is the charge of each of these particles?
Answer:
Protons: Positive charge (+).
Neutrons: No charge (Neutral).
Electrons: Negative charge (-).

Question 13.
Electrons revolve around the nucleus. What is the charge of electrons?
Answer:
The charge of electrons is negative (-). Electrons are the subatomic particles that revolve around the nucleus of an atom. They carry a fundamental unit of negative electric charge.

Question 14.
Table 10.2: Find the Charge
Answer:

No. of Protons	No. of Electrons	Charge (Positive/Negative/Neutral)
26	26	Neutral
26	24	Positive
17	16	Positive

Answer the questions given below based on the table
Question 15.
What is the reason for an atom to be electrically neutral?
Answer:
An atom is electrically neutral because it has an equal number of positive protons and negative electrons.

Question 16.
What is the charge obtained if the number of electrons in an atom is greater than the number of protons?
Answer:
The atom obtains a negative charge.

Question 17.
What is the charge obtained if the number of protons in an atom is greater than the number of electrons?
Answer:
The atom obtains a positive charge.

Question 18.
Table 10.3: Charging by Rubbing

Answer:

Textbook Page No : 171 & 172

Question 19.
What charge do balloons gain when rubbed with wool?
Positive / Negative
Answer:
Negative charge (Rubber gains electrons from wool).

Question 20.
What charge does the wool gain after rubbing?
Positive / Negative
Answer:
Positive. (Wool loses electrons to the balloons).

Question 21.
Is attraction or repulsion the most suitable indication to confirm the charge of an object?
Answer:
Repulsion

Question 22.
If two objects attract each other, can it be confirmed that both are charged? What if they repel?
Answer:
If they attract, it cannot be confirmed that both are charged (since a charged object attracts a neutral object). If they repel, it can be confirmed that both are charged with the same type of charge

Question 23.
Can static electricity light up a bulb?
Answer:
No. Static electricity means the charge “remains in the same place.” A light bulb needs a continuous flow of charge (electric current) to light up. A static discharge (like a small spark) is a very brief flow and is not enough to light a standard bulb.

Textbook Page No : 171

Question 24.
Complete the observation table: Answer:
Answer:

After touching the glass rod	Observations (Attraction / Repulsion)
Between the pith balls	Repulsion (Both balls gain the same charge).
Between the pith balls and glass rod	Repulsion (Both have the same charge).

Question 25.
What charge does a glass rod acquire when rubbed with a silk cloth?
Answer:
Positive charge.

Question 26.
What is the charge of the pith balls (after touching the glass rod)?
Answer:
Positive charge (They repel the positively charged rod). Yes, the pith balls were charged by contact (conduction).

Textbook Page No : 174

Question 27.
The method of charging a metal sphere using a negatively charged glass rod is shown in the picture. Observe the picture and write down the different steps.

Answer:

Step	Action	Short Result
1. Induction	Bring the negatively charged rod near the neutral sphere.	Positive charge is attracted to the near side, negative charge is repelled to the far side.
2. Earthing	Touch the far side of the sphere to the ground while the rod is still near.	Repelled negative charge flows into the Earth.
3. Remove Earthing	Remove the ground connection first.	The positive charge is trapped on the sphere.
4. Remove Rod	Remove the charged rod.	The trapped positive charge spreads evenly, leaving the sphere permanently positively charged.

Question 28.
What is the charge of the paint droplets?
Answer:
Negative (-)

Question 29.
What is the charge of the part to be painted?
Answer:
Positive

Question 30.
Why do paint droplets stick to the charged surface?
Answer:
Unlike charges attract each other.

Textbook Page No : 175 & 176

Photocopier (Fig 10.14):

Question 31.
What is the charge given to the toner particles here?
Answer:
Negative (-).

Question 32.
What causes the toner particles to stick to the drum as it rotates?
Answer:
The negative toner is attracted to the positive areas on the drum (where the image is).

Question 33.
What is the charge given to the paper?
Answer:
Negative

Question 34.
What is the charge of the paint droplets?
Answer:
Positive (+) (A stronger positive charge than the drum).

Question 35.
Why do the toner particles stick to the paper?
Answer:
The negative toner is more strongly attracted to the positively charged paper and transfers from the drum to the paper.

Question 36.
Image 10.16 (Person touching a doorknob): Discuss the reasons for small sparks.

Answer:
Friction (e.g., from walking) causes a static charge to accumulate on the person’s body. When the person touches the metallic doorknob (grounded conductor), the stored charge discharges rapidly, creating a spark as it flows to the Earth.

Question 37.
Damage to Electronic Components (Fig. 10.17)

Answer:
Yes, the rapid flow of high voltage from the human body (Electrostatic Discharge or ESD) can damage or destroy the delicate, small-scale electronic components in the circuit.

Question 38.
Charged Pen/Scale Touched to the Ground
Answer:
It will no longer attract pieces of paper. The object becomes neutralized because the Earth, being an “electron bank,” transfers electrons to or from the object.

Question 39.
Neutralization by Earthing (Fig. 10.19 a & 10.19b)

Answer:

• Negatively Charged Object (Excess Electrons): The excess electrons flow from the object to the Earth (down arrow).
• Positively Charged Object (Deficient Electrons): Electrons flow from the Earth to the object (up arrow).

Textbook Page No : 177 & 178

Child on Slide (Fig 10.20):

Question 40.
How did the charge accumulate in the hair?
Answer:
Through friction between the child’s body/hair and the plastic slide.

Question 41.
Can you suggest a method to neutralise the charge?
Answer:
Earthing. The child can touch the ground, or a metal part of the slide structure that is connected to the ground.

Question 42.
Write about the earthing mechanism in dangerous situations.
Answer:
In situations where static electricity is dangerous (e.g., handling sensitive electronics), earthing is used to neutralize accumulated charge. The Earth acts as an “electron bank” and allows any excess charge on the object/person to flow safely to the ground. This prevents a sudden, damaging Electrostatic Discharge (ESD).

Question 43.
What will happen if a negatively charged rod is placed near a metal sphere?
Answer:
A redistribution of charges takes place in the metal sphere, a process called electrostatic induction.

Textbook Page No : 179 & 180

Question 44.
The metal sphere is earthed. Now, remove the earthing and then the charged rod. Won’t the metal sphere acquire a permanent charge?
Answer:
Yes, the sphere will acquire a permanent positive charge. This is achieved by:

1. Earthing while the rod is nearby: Repelled electrons flow from the sphere into the Earth.
2. Removing the earthing (trapping the positive charge).
3. Removing the rod (allowing the positive charge to spread).

Question 45.
Write down the parts of an electroscope.
Answer:

• Metal sphere
• Glass jar
• Metallic conductor (Rod)
• Golden leaves (or Aluminum foil leaves)

Question 46.
What do you observe? What is the reason?
Answer:
The aluminum foil leaves will diverge (move apart).
Reason: The charged rod induces the same type of charge onto both leaves through induction. Since like charges repel, the leaves push each other apart.

Question 47.
Bring a neutral object nearby. Do the leaves diverge now?
Answer:
No, neutral objects cause no movement in the leaves.

Question 48.
When plate A is positively charged, observe the induction of charges in B. What if plate B is earthed?
Answer:

• Induction on B: Plate A’s positive charge attracts negative charges to the near side of B and repels positive charges to the far side of B.
• Plate B Earthed: Electrons flow up from the Earth to neutralize the repelled positive charges on plate B, trapping the net negative charge on the near side.

Question 49.
Draw the distribution of charges (Fig. 10.28).

Answer:

1. Plate A: Positively charged (+).
2. Plate B: Negatively charged (-).

Textbook Page No : 181 & 182

Question 50.
How are charges distributed on a metal surface?
Answer:

1. In electrical conductors, the charge is distributed only on the surface.
2. The amount of charge will be very high at the sharp edges (or points) of the conductor.

Question 51.
How does the cloud get charged?
Answer:
Various air currents cause friction (rubbing) between ice crystals and water droplets, leading to the accumulation of electric charges in the clouds.

Question 52.
What types of charges are accumulated in clouds?
Answer:
Both positive and negative charges.

Question 53.
Why are the objects on Earth oppositely charged?
Answer:
Due to electrostatic induction. The highly charged cloud induces an opposite charge on objects directly below it on the Earth’s surface.

Question 54.
What all can we do to protect ourselves from lightning?
Answer:

• Do not seek shelter under tall or isolated trees.
• Do not attempt to operate electrical appliances.
• Stay inside a fully enclosed building or a car.

Question 55.
Why is a positive charge induced at the sharp points of the lightning conductor when clouds are negative?
Answer:
Reason: The high concentration of charge at sharp points and the principle of induction cause the opposite charge (positive) to be strongly induced and discharged into the atmosphere.

Question 56.
What if the clouds have a positive charge?
Answer:
A negative charge will be induced at the sharp points of the lightning con¬ductor, following the rule that opposite charges are induced.

Question 57.
First Aid if a Person is Struck by Lightning
Answer:

• Lay the person flat in a well-ventilated area.
• Massage the entire body to warm it up (to help with circulation).
• Provide artificial respiration
• Apply intermittent pressure on the chest (CPR) if you are trained.
• Call for emergency medical help immediately.

Class 8 Basic Science Chapter 10 Question Answer Extended Activities

Question 1.
Seat a child on a plastic chair in such a way that both their feet do not touch the ground. Charge the chair using a woolen cloth. Let the child hold one terminal of a Neon bulb, and make another person touch the other terminal. What do you observe? Write down the observations.
Answer:
Setup: A child sits on a plastic chair (insulator) with feet off the ground (isolated from Earth). You charge the plastic chair by rubbing it with wool. This charges the child’s body by induction. (For example, if the chair becomes negative, it will repel electrons in the child’s body to their hands/head).

Observation: When the child holds one terminal of the neon bulb and another person (who is earthed/standing on the ground) touches the other terminal, the neon bulb will flash briefly.

Reason: The child has a high static charge (potential). The other person is at Earth’s potential (zero). The neon bulb creates a path for the static charge to discharge from the child, through the bulb, to the other person, and into the Earth. This tiny, quick flow of current is enough to make the neon gas inside the bulb light up for a moment.

Question 2.
Prepare and present a seminar on Van de Graff generator.
Answer:
Van de Graaff Generator

A Van de Graaff generator is a machine designed to build up an extremely high static electric charge on a large metal sphere. It works by using a moving belt to physically carry charges from a source at the bottom and deposit them onto the sphere at the top. It is famously used in science demonstrations to make a person’s hair stand on end when they touch it (for the same reason the balloon makes hair stand up, just on a much larger scale!).

Static Electricity Class 8 Notes

Class 8 Basic Science Static Electricity Notes Kerala Syllabus

Static Electricity (സ്ഥിത വൈദ്യുതി)
When you rub a balloon on dry hair, your hair is attracted to the balloon. Similarly, a plastic pen rubbed on hair can attract small pieces of paper. This ability of objects to attract after being rubbed is due to electric charge.

Static electricity is the result of an imbalance of electric charges on the surface of an object.

“If electric charge remains in the same place without being able to flow, such electricity is called static electricity.”
Example: Rubbing a balloon on dry hair causes the hair to be attracted to the balloon.
ഒരു വസ്തുവിൽ ഉണ്ടാകുന്ന വൈദ്യുത ചാർജു കൾ ഒരിടത്ത് തന്നെ തങ്ങിനിൽക്കുന്നതിനെയാണ് സ്ഥിത ർജുകൾക്ക് ആകർഷിക്കാനുള്ള കഴിവുണ്ട്. ഉദാ ഹരണത്തിന്, ഒരു പ്ലാസ്റ്റിക് പേന മുടിയിൽ ഉര സി ചെറിയ കടലാസ് കഷണങ്ങൾക്ക് അടുത്തേ ക്ക് കൊണ്ടുവരുമ്പോൾ അവ ആകർഷിക്കപ്പെടു ന്നു. ഇത് സ്ഥിത വൈദ്യുതി മൂലമാണ്.

The Atom (ആറ്റം)
All matter is made of tiny particles called atoms. The charges we observe come from the particles inside the atom.

An atom has two main parts:
1. Nucleus (the center): Contains:
Protons (have a positive charge ‘+’)
Neutrons (have no charge / are neutral)

2. Orbits (the paths around the nucleus): Contain:
Electrons (have a negative charge ‘-‘)

An object gets charged by the transfer of electrons. Protons do not move.
എല്ലാ പദാർത്ഥങ്ങളും ആറ്റങ്ങൾ എന്നറിയപ്പെടുന്ന അതിസൂക്ഷ്മ കണങ്ങളാൽ നിർമ്മിതമാണ്. ഒരു ആറ്റത്തിന്റെ കേന്ദ്രഭാഗമാണ് ന്യൂക്ലിയസ്. ഇതിൽ പോസിറ്റീവ് ചാർജുള്ള പ്രോട്ടോണുകളും (‘+’) ചാർജില്ലാത്ത ന്യൂട്രോണുകളും അടങ്ങിയിരിക്കു ന്നു. ന്യൂക്ലിയസിന് ചുറ്റുമുള്ള പാതകളിൽ നെഗ റ്റീവ് ചാർജുള്ള ഇലക്ട്രോണുകൾ (‘-‘) കറങ്ങി ക്കൊണ്ടിരിക്കുന്നു.

• Loses electrons (e-) → Positively charged
  (ഇലക്ട്രോൺ നഷ്ടപ്പെട്ടാൽ പോസിറ്റീവ് ചാർജ്).
• Gains electrons (e-) → Negatively charged
  (ഇലക്ട്രോൺ നേടിയാൽ നെഗറ്റീവ് ചാർജ്).

Electric Charge

• Electrically Neutral Object: Contains an equal number of protons and electrons (net charge is zero).
• Positively Charged Object: Has a deficiency of electrons (more protons than electrons).
• Negatively Charged Object: Has an excess of electrons (more electrons than protons).

Characteristics of Electric Charges
1. Like Charges Repel: Objects carrying the same type of charge (e.g., two positive charges or two negative charges) will push each other away.

when two balloons are rubbed with the same piece of wool, they both gain the same type of charge (negative charge, as rubber gains electrons from wool). When brought near each other, they move apart.
സജാതീയ ചാർജുകൾ (Like Charges): ഒരേത രം ചാർജുകൾ (പോസിറ്റീവും പോസിറ്റീവും, അ ല്ലെങ്കിൽ നെഗറ്റീവും നെഗറ്റീവും) പരസ്പരം വികർ ഷിക്കുന്നു. (ഉദാ: കമ്പിളിയിൽ ഉരസിയ രണ്ട് ബല ണുകൾ പരസ്പരം അകന്നുപോകുന്നു).

2. Unlike Charges Attract: Objects carrying opposite charges (one positive and one negative) will pull each other closer.
The wool (which lost electrons) is now positively charged. The balloon (which gained electrons) is negatively charged. When the wool is brought near the balloon, the balloon is attracted to it.

സജാതീയ ചാർജുകൾ (Like Charges): ഒരേത രം ചാർജുകൾ (പോസിറ്റീവും പോസിറ്റീവും, അ ല്ലെങ്കിൽ നെഗറ്റീവും നെഗറ്റീവും) പരസ്പരം വികർ ഷിക്കുന്നു. (ഉദാ: കമ്പിളിയിൽ ഉരസിയ രണ്ട് ബല ണുകൾ പരസ്പരം അകന്നുപോകുന്നു).

3. Charged Objects Attract Neutral Objects: A charged object can induce temporary charge separation in a neutral object, resulting in a net attractive force.

A charged object (like the acrylic sheet) can also attract a neutral, uncharged object (like the thermocol balls).

ചാർജുള്ള ഒരു വസ്തുവിന് ചാർജില്ലാത്ത (netural) വസ്തുക്കളെയും ആകർഷിക്കാൻ കഴിയും.

A charged object can attract a neutral object. Therefore, repulsion is the sure test to confirm if an object is charged.
ആകർഷണം (attraction) ചാർജുള്ള വസ്തു വും ചാർജില്ലാത്ത വസ്തുവും തമ്മിലും നടക്കാം. എന്നാൽ വികർഷണം (repulsion) ഒരേതരം ചാർജുള്ള വസ്തുക്കൾ തമ്മിൽ മാത്രമേ നടക്കൂ. അതിനാൽ, ചാർജ് ഉണ്ടോ എന്ന് ഉറപ്പിക്കാനുള്ള മാർഗ്ഗം വികർഷണമാണ്.

Methods of Charging (ചാർജ് ചെയ്യുന്ന രീതികൾ)

1. Charging by Friction (ഘർഷണം): Charging by rubbing two objects together (e.g., glass rod and silk).
2. Charging by Conduction (ചാലകം വഴിയുള്ള ചാർജിംഗ്)
   • “Charging by conduction is the method of charging an object by direct physical contact with a charged object.”
   • The object gets the SAME charge. (തൊടുമ്പോൾ, അതേ ചാർജ് ലഭിക്കുന്നു.)
3. Charging by Induction (പ്രവേശനം):
   • “Charging by induction is the method of charging an object without direct physical contact of a charged object.”
   • The object gets the OPPOSITE charge. (തൊടാതെ അടുത്ത് കൊണ്ടുവരുമ്പോൾ, വിപ രീത ചാർജ് ലഭിക്കുന്നു).

Applications of Static Electricity (സ്ഥിത വൈദ്യുതിയുടെ ഉപയോഗങ്ങൾ)

We can use the properties of static electricity (like charges repel, unlike charges attract) in useful ways.
A. Electrostatic Spray Painting
This method is used in workshops to paint vehicles efficiently.

□ Process:

1. The nozzle of the spray gun gives the tiny paint droplets a negative charge (-).
2. The car body (or object to be painted) is given the opposite positive charge (+).

□ Result: Because unlike charges attract, the negative paint droplets are strongly attracted to the positive car body. This method reduces paint waste and ensures the paint covers the surface evenly, even “wrapping around” edges.
‘വിപരീത ചാർജുകൾ ആകർഷിക്കും’ (Unlike charges attract) എന്ന തത്വം ഇവിടെ ഉപ യോഗിക്കുന്നു. പെയിന്റ് കണങ്ങൾക്ക് നെഗറ്റീവ് ചാർജും കാറിന് പോസിറ്റീവ് ചാർജും നൽകുന്നു. ഇത് പെയിന്റ് പാഴാകാതെ കാറിൽ കൃത്യമായി പ റ്റിപ്പിടിക്കാൻ സഹായിക്കുന്നു.

B. Photocopier Machine
Photocopiers also use static electricity to create a copy.

□ Process:

1. A special drum inside is given a positive charge (+) in the exact shape of the letters or images on the original paper.
2. The toner (a fine black powder) is given a negative charge (-).
3. The negative toner is attracted to the positive areas of the drum.
4. A sheet of paper is then given a stronger positive charge (+) than the drum.
5. The negative toner is pulled from the drum onto the paper because of this stronger attraction.
6. Finally, the paper is heated to melt the toner and make the copy permanent.

Situations where static electricity is harmful (സ്ഥിത വൈദ്യുതി ദോ ഷകരമാകുമ്പോൾ)

While useful, a sudden discharge of static electricity can be a problem.

Electric Shock : When you walk on a carpet or slide across a car seat, friction can build up a large static charge on your body. When you touch a metal doorknob or the car door, this charge suddenly discharges as a spark, giving you a small, sharp shock.

Damaging Electronics : This same sudden discharge (spark) is very dangerous for sensitive electronic components, like those inside a mobile phone or computer. A person with a static charge on their hand can permanently damage a circuit board just by touching it. This is why technicians wear antistatic gloves.
ഘർഷണം മൂലം നമ്മുടെ ശരീരത്തിൽ സ്ഥിത വൈദ്യുതിയുടെ ചാർജ് അടിഞ്ഞുകൂടാം. ഇത് ഒരു ലോഹ വസ്തുവിൽ തൊടുമ്പോൾ ഒരു ‘സ്പാ ർക്ക്’ ആയി ഡിസ്ചാർജ് ചെയ്യപ്പെടുന്നു (ഇതാണ് നമുക്ക് ചെറിയ ഷോക്ക് അടിക്കുന്നത്. ഈ ഡി സാർജ് ഇലക്ട്രോണിക് ഉപകരണങ്ങളിലേക്കാ ണെങ്കിൽ, അത് ആ ഉപകരണത്തെ നശിപ്പിക്കാൻ സാധ്യതയുണ്ട്.

Earthing (എർത്തിംഗ്) grounding
Earthing is the process of connecting a charged object to the Earth to neutralize it.

“The Earth is an electron bank. Due to its size and conductivity, the Earth can donate and receive electrons. Therefore, charged objects are neutralised when earthed.”

How it works:

• A positively charged object pulls electrons (e-) from the Earth.
• A negatively charged object pushes excess electrons (e-) to the Earth.

• Petrol pump nozzles are earthed to prevent sparks (from friction) that could cause a fire.

ചാർജുള്ള ഒരു വസ്തുവിനെ ഭൂമിയുമായി ബന്ധി പ്പിച്ച് അതിനെ നിർവീര്യമാക്കുന്ന (neturalize) പ്രക്രിയയാണ് എർത്തിംഗ്.

പോസിറ്റീവ് ചാർജുള്ള വസ്തുവിനെ എർത്ത് ചെ യുമ്പോൾ, ഭൂമിയിൽ നിന്ന് ഇലക്ട്രോണുകൾ ആ വസ്തുവിലേക്ക് പ്രവഹിച്ച് അതിനെ നിർവീര്യമാ ക്കുന്നു.

നെഗറ്റീവ് ചാർജുള്ള വസ്തുവിനെ എർത്ത് ചെ യുമ്പോൾ, ആ വസ്തുവിൽനിന്നും അധികമുള്ള ഇലക്ട്രോണുകൾ ഭൂമിയിലേക്ക് പ്രവഹിക്കുന്നു.

Charging by Induction (പ്രവേശനം വഴിയുള്ള ചാർജിംഗ്)



Process (Figs 10.22, 10.23, 10.24):

1. Step 1 : A negatively charged rod is brought near (not touching) a neutral metal sphere.
2. Step 2 : (Electrostatic Induction): The negative rod repels the free electrons (-) in the sphere, causing them to move to the far side. The side of the sphere near the rod becomes positive (+) due to a lack of electrons. This separation is called redistribution of charges.
3. Step 3: While the rod is still held nearby, the sphere is earthed. The repelled electrons get an escape path and flow from the sphere into the Earth.
4. Step 4: The earthing is removed first. The sphere is now left with an overall positive charge, which is still held near the rod.
5. Step 5: The rod is removed. The positive charges (which were crowded near the rod) now spread out evenly over the surface of the sphere.
   • The sphere has become permanently positively charged. Notice that the charge it gained is opposite to the charge of the rod used (negative rod → positive sphere).

പ്രേരണ മുഖേനയുള്ള ചാർജിംങ് : ചാർജുള്ള ഒരു വസ്തുവിനെ (rod) മറ്റൊരു വസ്തുവിന്റെ (sphere) അടുത്തേക്ക് (തൊടാതെ) കൊണ്ടുവന്ന് ചാർജ് ചെയ്യുന്ന രീതിയാണിത്.

1. നെഗറ്റീവ് ദണ്ഡ് അടുത്ത് വരുമ്പോൾ, ഗോള ത്തിലെ ഇലക്ട്രോണുകൾ വികർഷിച്ച് ദൂരേക്ക്മാറുന്നു.
2. ഈ സമയത്ത് ഗോളത്തെ എർത്ത് ചെയ്യു മ്പോൾ, ഈ ഇലക്ട്രോണുകൾ ഭൂമിയിലേക്ക് ഒഴുകിപ്പോകുന്നു.
3. ആദ്യം എർത്തിംഗ് മാറ്റുക. അതിനുശേഷം ദണ്ഡ് മാറ്റുക.
4. ഇപ്പോൾ ഗോളത്തിന് സ്ഥിരമായ പോസിറ്റീവ് ചാർജ് (ഇലക്ട്രോണുകളുടെ കുറവ് ലഭിക്കു ന്നു. ഇൻഡക്ഷൻ വഴി ലഭിക്കുന്ന ചാർജ്, ഉപ യോഗിച്ച ദണ്ഡിന്റെ ചാർജിന് വിപരീതമായി രിക്കും.

Electroscope
An electroscope is a scientific instrument used to detect the presence of electric charge on an object.

Parts (Fig 10.25): It consist’s of a metal sphere (or disc) on top, a metal rod, and two very thin, lightweight “leaves” (often gold or aluminium foil) at the bottom, all enclosed in a glass jar to protect from air currents.

How it Works (Working Principle):

1. Bring a charged object (e.g., a positively charged rod) near the top metal sphere.
2. By induction, electrons (-) from the leaves and rod are attracted upwards towards the positive rod.
3. This leaves both the leaves at the bottom with a deficit of electrons, so both leaves become positively charged.
4. Since like charges repel, the two positive leaves move apart, or “diverge”.
5. If you bring a neutral object near the electroscope, nothing happens because it does not cause the charges to separate.

ഒരു വസ്തുവിന് ചാർജുണ്ടോ എന്ന് കണ്ടെത്താനു ള്ള ഉപകരണമാണ് ഇലക്ട്രോസ്കോപ്പ്. ചാർജുള്ള ഒരു വസ്തു ഇതിന്റെ മുകളിലെ ലോഹഗോളത്തിന ടുത്ത് കൊണ്ടുവരുമ്പോൾ, ഇൻഡക്ഷൻ മൂലം താഴെയുള്ള നേർത്ത ഇലകൾക്ക് (leaves) ഒരേത രം ചാർജ് ലഭിക്കുന്നു. സജാതീയ ചാർജുകൾ വികർഷിക്കുന്നതിനാൽ (like charges repel), ഈ ഇലകൾ പരസ്പരം അകലുന്നു (diverge).

Capacitor
A capacitor is a device used for storing electric charge.


How it Works (Fig 10.27, 10.28): A simple capacitor consists of two metal plates placed very close together, separated by an insulator.

• When one plate (A) is given a charge (e.g., positive), it induces an opposite charge (negative) on the near side of the second plate (B).
• If plate B is earthed, the repelled positive charges flow to the Earth, “locking” the negative charges on plate B. This allows even more positive charge to be stored on plate A.
  • Capacitance: The ability of a capacitor to store charge is called capacitance. Its SI unit is the Farad (F).
  • Dielectric: The insulating material between the plates (like paper, air, or polyester) is called a dielectric. It helps to increase the capacitance.

വൈദ്യുത ചാർജ് സംഭരിച്ചുവെക്കാൻ (store eletcric charge) ഉപയോഗിക്കുന്ന ഒരു ഉപകരണമാ ണ് കപ്പാസിറ്റർ. ഇതിന്റെ ചാർജ് സംഭരിക്കാനുള്ള കഴിവിനെ കപ്പാസിറ്റൻസ് എന്ന് പറയുന്നു. ഇതി ന്റെ യൂണിറ്റ് ഫാരഡ് (F) ആണ്. ഫാനുകളിലും മോട്ടോറുകളിലും മറ്റ് ഇലക്ട്രോണിക് ഉപകരണങ്ങ ളിലും ഇത് വ്യാപകമായി ഉപയോഗിക്കുന്നു.

Distribution of Electric Charges ((ചാർജുകളുടെ വിതരണം))
Where do charges stay on a conductor?

1. On the Surface: In electrical conductors, charge is always distributed only on the outer surface.
2. At Sharp Edges: The amount of charge (charge density) will be much higher at the sharp edges or pointed parts of a conductor.

ഒരു ചാലകത്തിന് (conductor) ചാർജ് നൽകു മ്പോൾ, ആ ചാർജ് അതിന്റെ പ്രതലത്തിൽ (surface) മാത്രമാണ് വിതരണം ചെയ്യപ്പെടുന്നത്. ചാ ലകത്തിന്റെ കൂർത്ത അഗ്രങ്ങളിൽ (sharp edges) ചാർജിന്റെ അളവ് വളരെ കൂടുതലായിരിക്കും. (ഇടിമിന്നൽ രക്ഷാചാലകം അഥവാ lightning conductor പ്രവർത്തിക്കുന്നത് ഈ തത്വമനുസരി ച്ചാണ്).

Lightning and Lightning Conductor (ഇടിമിന്നലും രക്ഷാചാലകവും)
Lightning
Lightning is a massive-scale natural example of static electricity and electrostatic discharge.
How does lightning occur?

1. Charging the Clouds: Cloud friction generates massive static charge (+ & -).
2. Induction on Earth: Charged cloud induces opposite charge on the Earth’s surface.
3. Electric Discharge: WExcessive charge discharges through the air to the Earth as a giant spark (lightning).
1. മേഘങ്ങളിൽ ഘർഷണം (friction) മൂലം വൻതോതിൽ വൈദ്യുത ചാർജ് (പോസിറ്റീവും നെഗറ്റീവും) ഉണ്ടാകുന്നു.
2. ചാർജ് ചെയ്ത മേഘം, ഇൻഡക്ഷൻ (induction) വഴി ഭൂമിയുടെ ഉപരിതലത്തിൽ വിപരീത ചാർജ് (opposite charge) ഉണ്ടാക്കുന്നു.
3. ചാർജിന്റെ അളവ് വളരെ കൂടുമ്പോൾ, അത് വാ യുവിലൂടെ ഭൂമിയിലേക്ക് ഒരു ഭീമൻ സ്പാർക്കാ യി ഡിസാർജ് ചെയ്യുന്നു. ഇതാണ് ഇടിമിന്നൽ.
□ Charge Distribution: On a conductor, charge stays on the surface and is most concentrated at sharp points. (കുർത്ത അഗ്രങ്ങളിൽ ചാർജ് കേന്ദ്രീകരിക്കുന്നു).

Lightning Conductor (Arrester)
A metal rod installed on the top of tall buildings and connected by a thick wire to a metal plate deep in the ground.

• Function: It provides a safe, low-resistance path for the lightning strike’s current to flow directly into the Earth, protecting the structure from damage.
• Note: The charge naturally concentrates and discharges from the sharp points of the conductor, neutralizing the cloud’s charge gradually. A poorly earthed conductor is dangerous as it cannot safely handle the massive current.

Lightning Arrester vs. Lightning Conductor

• Lightning Conductor (രക്ഷാചാലകം) protects the building structure from a direct hit.
• Lightning Arrester is a different device used to protect the electrical system (like transformers at a KSEB substation, Fig 10.35) from sudden high-voltage surges caused by lightning.

Personal Safety Measures During Lightning

• Do not stand under tall, isolated trees.
• Do not touch electrical appliances or metallic objects.
• The safest places are inside a fully enclosed building or a car (the metal body acts as a Faraday cage).

First Aid for Lightning Strike

• If a person is struck, follow these steps:
• Lay the person flat in a Well-ventilated area.
• Massage the entire body to warm it up.
• Provide artificial respiration.
• Apply intermittent pressure on the chest.