Electric Charges and Fields Class 12 Physics 2026-27 | Chapter 1
Electric Charges and Fields is Chapter 1 of CBSE Class 12 Physics and the opening chapter of Unit I — Electrostatics. This chapter hub brings the complete study path together: notes, important questions, MCQs, numericals, case-based questions, assertion–reason practice, PYQs, quick revision and a chapter test.
Use the sequence Learn → Practise → Solve → Revise → Test instead of studying the chapter from a single page. Each resource below serves a different stage of CBSE board-exam preparation.
You are on the Chapter 1 hub. Use the Physics hub for the full Class 12 chapter map, or continue directly to Chapter 2 after finishing this chapter.
Open Class 12 Physics Hub → · Go to Chapter 2 →CBSE 2026–27 Syllabus Scope
The official CBSE 2026–27 Physics curriculum lists the following Chapter 1 content. Chapters 1 and 2 together form Unit I — Electrostatics, which carries 16 marks at the unit level; the curriculum table does not assign a separate fixed mark allocation to Chapter 1.
Electric charges and their basic properties, including the conservation of charge.
Force between two point charges, dependence on charge and separation, and the vector nature of electrostatic force.
Force due to multiple point charges and the superposition principle, including continuous charge distributions.
Electric field, field due to a point charge, and the representation of an electric field using field lines.
Electric dipole, electric field due to a dipole, and torque on a dipole placed in a uniform electric field.
Electric flux through a surface and the physical meaning of flux in an electric field.
Statement of Gauss's theorem and its use for calculating electric field for suitable symmetric charge distributions.
Electric field due to an infinitely long straight wire, an infinite plane sheet and a uniformly charged thin spherical shell, including inside and outside the shell.
Chapter Resources
All nine Chapter 1 resources are live on Learn Revise Hub. Choose the resource that matches your next study task, then move forward through the chapter sequence.
Recommended Study Sequence
Exam-Focus Checklist
For board preparation, make sure you can move between the concept, formula, diagram and application—not just recall the final equation.
Charge properties, Coulomb's law, superposition, electric field, field lines, electric dipole, electric flux and Gauss's theorem.
Point-charge field, dipole-related relations, electric flux and standard Gauss-law field results within the prescribed syllabus.
Multiple-charge systems, dipole in a uniform field, and Gauss-law applications for a long straight wire, infinite plane sheet and thin spherical shell.
Write SI units, identify vectors and directions, state the Gaussian surface used, and show the key reasoning before the final numerical result.
High-Priority Formula Map
| Concept | Key relation | What to watch |
|---|---|---|
| Coulomb's law | F = (1/4πε0) |q1q2|/r2 | Force is a vector; direction depends on whether charges attract or repel. |
| Electric field | E = F/q0 | Define the field using a positive test charge; do not confuse field with force. |
| Point-charge field | E = (1/4πε0) q/r2 | Direction is radial and depends on the sign of the source charge. |
| Dipole moment | p = qd | Direction is from negative charge to positive charge. |
| Torque on dipole | τ = pE sinθ | Torque is zero when the dipole is parallel or antiparallel to the field. |
| Electric flux | Φ = E·A = EA cosθ for a uniform field and flat surface | θ is the angle between E and the area vector. |
| Gauss's theorem | ∮E·dA = qenclosed/ε0 | Choose a Gaussian surface that matches the symmetry of the charge distribution. |
What Students Commonly Mix Up
- Force vs electric field: force depends on the test charge; electric field is defined per unit positive test charge.
- Field vs flux: electric field is a vector; electric flux is a scalar quantity for a specified surface and field configuration.
- Field lines vs actual paths: field lines are a representation of the field direction and strength; they are not physical wires or particle trajectories.
- Dipole moment direction: remember that p points from the negative charge toward the positive charge.
- Gauss's theorem vs symmetry: Gauss's theorem is general, but the standard direct field calculations require a sufficiently symmetric charge distribution and an appropriate Gaussian surface.
- Enclosed charge: in Gauss's law, the net charge enclosed by the closed Gaussian surface appears on the right-hand side.
- Inside a spherical shell: for the ideal uniformly charged thin spherical shell in electrostatic conditions, the field inside is zero.
Gauss's Theorem — Application Checklist
When a numerical asks you to use Gauss's theorem, think about the symmetry before writing equations.
Use a cylindrical Gaussian surface coaxial with the line charge so the field magnitude is constant over the curved surface.
Use a pillbox-style Gaussian surface crossing the sheet and exploit the planar symmetry.
Use a spherical Gaussian surface centered on the shell. The enclosed charge determines the outside field.
A Gaussian surface inside the shell encloses no charge, giving zero electric field for the ideal uniformly charged thin shell.
Chapter 1 Preparation Checklist
- I can state Coulomb's law and identify the direction of electrostatic force.
- I can apply superposition to more than one charge.
- I can calculate the electric field due to a point charge.
- I can interpret the basic rules of electric field lines.
- I can define electric dipole moment and calculate torque in a uniform field.
- I can calculate electric flux for a simple uniform-field/surface arrangement.
- I can state Gauss's theorem correctly.
- I can identify when Gauss's theorem can be used efficiently for a symmetric distribution.
- I can apply the standard field results for the infinite line, infinite plane sheet and thin spherical shell within the syllabus scope.
- I can solve a timed chapter test without relying on the answer key.
Continue to Chapter 2
After completing Electric Charges and Fields, continue with electric potential, potential energy, dielectrics, capacitors and capacitor combinations.
Open Chapter 2 Hub →Official CBSE Resources
Use the official curriculum as the primary source for the current syllabus scope.
View official CBSE Physics 2026–27 curriculum →Use the official SQP and marking scheme resources to understand the current board-exam format and marking expectations.
Open official CBSE Class XII SQP & MS page →After Chapter 1, continue with Chapter 2, or return to the complete Physics resource hub to choose another chapter.
Chapter 2 — Electrostatic Potential and Capacitance → · Class 12 Physics Hub →
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