NCERT Class 12 Physics Physics Part-I: Chapter 1 — 1 INTRODUCTION
This chapter introduces the fundamental concept of electric charge and electrostatics. It begins by describing common experiences related to static electricity, such as sparks from synthetic clothes and lightning. Electrostatics is defined as the study of forces, fields, and potentials arising from static charges. The historical discovery of electric charge by Thales of Miletus is mentioned, with the term 'electricity' originating from the Greek word for amber. The chapter explains the two types of electric charge – positive and negative – and their interactions: like charges repel, and unlike charges attract. It details experiments with glass rods, silk, plastic rods, and cat's fur to illustrate these principles. The concept of electrification through rubbing and the neutralization of opposite charges are also discussed, establishing the basis for understanding electric phenomena.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 12 |
| Subject | Physics |
| Book | Physics Part-I |
| Chapter | Chapter 1 — 1 INTRODUCTION |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 4 minutes |
| Word count | 636 |
Learning outcomes
- Understand the concept of static electricity and electrostatics.
- Identify the two types of electric charges: positive and negative.
- Explain the interactions between like and unlike charges (repulsion and attraction).
- Recognize the historical context of electric charge discovery.
- Understand the process of electrification by rubbing and charge neutralization.
Vocabulary
| Word | Meaning |
|---|---|
| Electrostatics | The study of forces, fields, and potentials arising from static charges. |
| Electric charge | A fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. |
| Electrification | The process of acquiring an electric charge, typically by rubbing. |
| Positive charge | One of the two types of electric charge, conventionally assigned to charges like those on a glass rod rubbed with silk. |
| Negative charge | The other type of electric charge, conventionally assigned to charges like those on a plastic rod rubbed with cat's fur. |
| Neutral | An object that has no net electric charge. |
| Repel | To push back or drive away; like charges repel each other. |
| Attract | To draw towards; unlike charges attract each other. |
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Practice questions
- What is electrostatics? Answer: Electrostatics is the study of forces, fields, and potentials arising from static charges.
- What are the two types of electric charge? Answer: The two types of electric charge are positive and negative.
- What happens when two like charges are brought near each other? Answer: Two like charges repel each other.
- What happens when two unlike charges are brought near each other? Answer: Two unlike charges attract each other.
- From which Greek word is 'electricity' derived, and what does it mean? Answer: The word 'electricity' is derived from the Greek word 'elektron', which means amber.
Practice MCQs
Q1. What phenomenon is studied in electrostatics?
Explanation: Electrostatics specifically deals with the study of forces, fields, and potentials arising from static charges.
Q2. Which of the following pairs of charges will repel each other?
Explanation: Like charges repel each other. Therefore, two negative charges will repel each other.
Q3. The Greek word 'elektron' means:
Explanation: The term 'electricity' is derived from the Greek word 'elektron', which means amber.
Q4. When a glass rod is rubbed with silk, what kind of charge does the glass rod acquire?
Explanation: By convention, the charge acquired by a glass rod when rubbed with silk is called positive.
Q5. What happens to the electric charges when two charged bodies neutralize each other?
Explanation: When unlike charges come in contact, they neutralize or nullify each other's effect.
Frequently asked questions
What is electrostatics?
Electrostatics is the branch of physics that deals with the study of forces, fields, and potentials arising from static electric charges.
What are the two fundamental types of electric charge?
The two fundamental types of electric charge are positive and negative.
What is the rule for the interaction between electric charges?
Like charges repel each other, and unlike charges attract each other.
How did the term 'electricity' originate?
The term 'electricity' is derived from the Greek word 'elektron', which means amber, as amber was one of the first materials observed to attract light objects when rubbed.
What happens when an object is electrified by rubbing?
When an object is electrified by rubbing, it acquires an electric charge, either positive or negative.
What does it mean for an object to be electrically neutral?
An object is electrically neutral when it has an equal amount of positive and negative charge, resulting in no net charge.
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NCERT Class 12 Physics — Physics Part-I — Chapter 1 — 1 INTRODUCTION. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.