Methods of Charging Class 12

    In this blog post, we will discuss Electric Charge and its types. We will also know about Methods of Charging like charging by friction, charging by conduction, and charging by induction. This article "Methods of Charging Class 12" will be the most helpful for class 12th students.

Methods of Charging

Electrostatics

    

    “Electrostatics is a branch of physics in which static charges and their effects are studied.”

Electric Charge 

    “Charge is that property of a substance, due to which it produces and experiences electric and magnetic effects.”

    Charge is an intrinsic property of the fundamental particles (or material) due to which it exerts or experiences electric and magnetic effects.

    When a charged particle is at rest, it only produces an electric field around itself. When a charged particle moves with a uniform velocity, it produces both an electric field and a magnetic field. If a charged particle is accelerated, it produces an electromagnetic wave.

`\star`    Protons are positively charged.

`\star`    Electrons are negatively charged.

`\star`    Neutrons have zero charge.

Basic Properties of Electric Charge

(i) The number of electrons and protons in an atom are equal, due to which atoms are electrically neutral.

(ii) A body gets a positive charge due to a lack of electrons.

(iii) An object gets a negative charge due to excess of electrons.

(iv) Like charges repel each other.

(v) Unlike charges attract each other.

Methods of Charging Class 12

(vi) Repulsion is a sure test of electrification.

(vii) Charge is a scalar quantity.

(viii) Electricity can be transferred from one object to another through the transfer of electric charge.

(ix) Charge is always linked with mass.

(x) Charge is always linked with mass. It cannot exist without mass.

(xi) Charge is conserved it means charge can neither be created nor be destroyed.

(xii) Total charge is quantized.

(xiii) “One coulomb is the quantity of charge transferred in one second.”

S.I. unit of charge is Coulomb (C). 

`\text{Coulomb} = Ampere \times sec`

`Q = I t`

(ivx) Dimensional formula of electric charge `q = [A^1 T^1]`

Types of Charge

What are the 2 types of electric charge?

There are two types of charges -

(i) Positive charge - 

    Positive charge shows the deficiency of electrons on a substance. If a substance has + 1 charge, it means that the substance is lacking one electron, and if a substance has +2 charge, it means that the substance is lacking two electrons.

(ii) Negative charge - 

    A negative charge shows the excess of electrons on a substance. If a substance has a -1 charge, it means that the substance has an excess of one electron and if a substance has a -2 charge, it means that the substance has an excess of two electrons.

Methods of Charging

There are three methods of charging

(i)    Charging by Friction

        If we rub two objects together, frictional electricity is generated, and there is a transfer of electrons between the two objects. The object giving up the electron acquires a positive charge, and the object receiving the electron acquires the same negative charge. For example, if we rub a glass rod with silk, the rod becomes positively charged and the silk becomes negatively charged.

Charging by Friction

Charging by Friction

        The cause of charging is the actual transfer of electrons from one material to the other.

        When an object is charged, there is a transfer of electrons and electrons have some mass of their own, so when an object loses an electron, it acquires a positive charge and the loss of an electron causes the mass of that object to drop. Some mass is also reduced, in the same way when an object accepts an electron, a negative charge comes on that object, and due to the acceptance of the electron, some mass of the object increases.

Sr. Number	+ ive charged materials	-ive charged materials
1	Glass Rod	Silk cloth
2	Fur or cat skin	Plastic rod and Ebonite rod
3	Woolen Cloth	Amber, Ebonite, Plastic, Rubber

        If we rub a copper rod with a woolen cloth, the copper rod gets charged, and then its entire charge goes to the earth through our body, due to which the copper rod does not get charged, if we use the handle of non-conductive material, then the conductor gets charged.

(ii)    Charging by Conduction

    When two objects are in contact, the charge is directly transferred from one to the other. In charging by conduction, the charged object comes in contact with the neutral object. Let us consider a positively charged conducting plate in contact with a neutral metal sphere. The neutral metal sphere gets charged due to contact with the charged plate.

Charging by Conduction

    Consider two conducting objects placed on an insulating stand. Let one of them be charged, and the other neutral. When we let them come in contact with each other (it can be positively or negatively charged), the charge gets redistributed on both conductors due to their repulsion. Thus, both conductors have the same type of charge. This means that even an uncharged conducting body gets charged. This is called charging by conduction (contact).

(iii)    Charging by Induction

Charging by Induction

 

       A metallic ball is placed on an insulated stand. When we take a negatively charged rod near it (without touching it), then the free electrons in the metallic ball move to the right due to the repulsion from the rod. These electrons cannot go out of the metallic ball, because the ball is placed on an insulator. Also, on the left of the ball, there is a decrease in the same amount of negative charge (not positive charge). These charges are called induction charges. The ball remains in its electrically neutral state.

    If the right surface of the ball is earthed by a conducting wire, then the negative charge flows to the earth. Not, if the contact with earth is broken and the charged rod is removed, then only a positive charge remains on the ball. In this process, there is no change in the charge on the rod. Earth gets that amount of negative charge which is equal to the magnitude of positive charge induced on the ball.

    We can charge the ball with a negative charge by taking a positively charged rod near the conducting ball and following the above-stated steps.

Points Related to the Charging of a Body

`\star` Two identical metallic balls of equal masses are taken. One of it has been given a positive charge Q whereas the other, has the same amount of negative charge. Theoretically, their masses will be different after charging. The mass of the negatively charged ball will be more. This is due to the fact that a negatively charged ball gets electrons which increase its mass whereas the positively charged ball A.

`\star` It is repulsion and not attraction which confirms the electrification because attraction can also perform between a charged and an uncharged body.

`\star` The value and detection of charge can be done by gold leaf electroscope, electrometer, voltameter, and ammeter.

`\star` When X-rays fall on a metallic surface, then electrons from the metal are emitted. Thus, the surface becomes positively charged.

Important Questions with Answers

Is Electric Charge a Vector Quantity?

Answers -    Electric charge is a scalar quantity because it has magnitude but no direction. A physical quantity that has no direction is known as a scalar quantity.

Define electric Charge.

Answers -    Electric charge is a property of matter that produces and experiences electric and magnetic effects.

What happens when a charged particle is at rest?

Answers -    When a charged particle is at rest, it produces only an electric field around itself.

When does a charged particle produce both electric and magnetic fields?

Answers -    A charged particle produces both electric and magnetic fields when it moves with a uniform velocity.

Is the charge conserved?

Answers -    Yes, the charge is conserved. It means charge cannot be created or destroyed.

What happens when a charged particle is accelerated?

Answers -    When a charged particle is accelerated, it produces an electromagnetic wave.

Name the materials that become positively charged when rubbed.

Answers -    Glass rod, fur, or cat skin.

Name two materials that become negatively charged when rubbed.

Answers -    Silk cloth, plastic rod, and ebonite rod.

What happens when a negatively charged rod is brought near a metallic ball on an insulated stand?

Answers -    Electrons in a ball move away, inducing a positive charge on one side and the other side will be negatively charged.

How can the charge on the ball be neutralized?

Answers -    We can neutralize the charge of the ball by earthing the ball through a conducting wire.

What effect do X-rays have on a metallic surface?

Answers -    X-rays will be the cause emission of electrons, resulting in a positively charged surface.

Related Questions

1. What is electrostatics?
2. What is electric charge? or Define electric charge.
3. What are the two types of electric charge?
4. Why are atoms electrically neutral?
5. What happens to the mass of a negatively charged ball compared to a positively charged ball?
6. What is an insulator in terms of electric charge?
7. Describe the law of conservation of charge.
8. Give an example of a conductor.
9. What is meant by the term "Charging by friction"?
10. How does a body acquire a negative charge?
11. Explain the process of charging by conduction.
12. Explain the process of charging by induction.
13. What is the SI unit of electric charge?
14. What is the dimensional formula of electric charge?
15. What is the charge of an electron?
16. What is the elementary charge?
17. Describe the charge of a proton.
18. What is meant by a neutral object?
19. Can two objects with the same type of charge attract each other? Why or why not?
20. Describe the behavior of charges on an insulator when it is charged by friction.
21. How does the movement of electrons differ between conductors and insulators?
22. Is charge always linked with mass?
23. Which test is sure test of electrification?
24. How does a body acquire a negative charge?
25. What happens when an object losses an electron?

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Chapter  1:  ELECTRIC CHARGE AND FIELDS

PHYSICS NOTES

• Electric Charge, Basic Properties of Electric Charge, Conductors and Insulators, and Methods of Charging
• Continuous Charge Distribution
• Coulomb's Law, Electroscope, Properties of Charge, Quantization of Charge.
• Coulomb's Law in Vector Form
• Principle of Superposition of Charges
• Electric Field and Field Lines, Types of Electric Field, Electric Field Due to a Point Charge, Electric Filed Due to a System of Charges, Electric Field lines and their Properties
• Gauss's Law of Electrostatic, Definition of Gauss's Law, Formula, Electric Charge and its Four Properties, Applications of Garss's Law, Gauss's Law, and Important Points
• Prove of Gauss Theorem in Electrostatics
• Electric Field due to Conducting Sphere
• Electric Field due to Conducting Hollow Sphere
• Electric Field due to Non-Conducting Sphere
• Electric Field due to Infinitely Long Charged Wire
• Electric Field due to Infinite Conducting Sheet of Charge..
• Electric Field due to Non-Conducting Plane Sheet
• Electric Flux
• Definitions of Electric Dipole, Electric Field due to Electric Dipole on Axial Line..
• Electric Field Due to Electric Dipole on Equatorial Line
• Torque on a Dipole in Uniform Electric Field
• Work Done in Rotating a Dipole..
• Dielectric Constant