NCERT Class 12 Physics Physics Part-I: Chapter 2 — 1 I 2.1 I 2.1 I 2.1 I 2.1 INTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION
This chapter introduces Electrostatic Potential and Capacitance in NCERT Class 12 Physics Part-I. It builds upon the concept of potential energy from Class XI, explaining that work done against a conservative force, like the Coulomb force between charges, is stored as potential energy. The chapter defines electrostatic potential energy and potential energy difference, emphasizing that the work done by an electrostatic field depends only on the initial and final points, not the path taken. This path-independence is a key characteristic of conservative forces. The text uses an example of moving a test charge against a repulsive force to illustrate the storage of potential energy and its relation to work done by external forces.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 12 |
| Subject | Physics |
| Book | Physics Part-I |
| Chapter | Chapter 2 — 1 I 2.1 I 2.1 I 2.1 I 2.1 INTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 4 minutes |
| Word count | 766 |
Learning outcomes
- Understand the concept of potential energy in the context of conservative forces.
- Define and calculate electrostatic potential energy.
- Explain the concept of potential energy difference between two points.
- Recognize Coulomb force as a conservative force.
- Understand the path-independence of work done by electrostatic fields.
Vocabulary
| Word | Meaning |
|---|---|
| Potential energy | Energy stored in an object due to its position or configuration. |
| Conservative force | A force for which the work done in moving an object between two points is independent of the path taken. |
| Coulomb force | The electrostatic force of attraction or repulsion between two charged particles. |
| Test charge | A small charge used to measure an electric field without significantly disturbing the field itself. |
| Electrostatic field | A region around a charged object where another charged object experiences a force. |
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Practice questions
- What is the condition for a force to be conservative? Answer: A force is conservative if the work done by it in moving an object between two points is independent of the path taken.
- Give an example of a conservative force other than Coulomb force. Answer: Gravitational force is another example of a conservative force.
- How is potential energy related to the work done by an external force? Answer: The work done by an external force against a conservative force is stored as potential energy.
Practice MCQs
Q1. Which of the following is an example of a conservative force?
Explanation: Coulomb force between stationary charges is a conservative force, similar to gravitational force.
Q2. If work done by an electric field is negative, what does it imply about the work done by an external force?
Explanation: Work done by an external force is the negative of the work done by the electric field. If electric field work is negative, external work is positive.
Q3. The potential energy of a charge in an electric field is related to:
Explanation: Work done by an external force against the electrostatic repulsive force gets stored as potential energy.
Q4. Path independence of work done is a characteristic of:
Explanation: The fundamental characteristic of a conservative force is that the work done is independent of the path taken.
Frequently asked questions
What is potential energy?
Potential energy is the energy possessed by an object due to its position or configuration, especially when work is done against a force like gravity or a spring force.
Is Coulomb force a conservative force?
Yes, the Coulomb force between two stationary charges is a conservative force.
What does it mean for a force to be conservative?
A force is conservative if the work done by it in moving an object between two points is independent of the path taken.
How is potential energy difference defined?
Potential energy difference between two points is defined as the work required to be done by an external force in moving a charge between those points without acceleration.
Why is path independence important for potential energy?
Path independence ensures that potential energy is a well-defined property of a point in a field, solely dependent on the location and not the history of movement.
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NCERT Class 12 Physics — Physics Part-I — Chapter 2 — 1 I 2.1 I 2.1 I 2.1 I 2.1 INTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION NTRODUCTION. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.