Electric Charges and Fields Class 12 Physics Chapter Test 2026-27

Electric Charges and Fields — Class 12 Physics Chapter Test
A 25-question board-style chapter test covering electric charge, Coulomb's law, superposition, electric field, dipole, flux and Gauss's law.

Class 12 Physics Chapter Test — Electric Charges and Fields

Use this test after completing the chapter resources. It is an original practice test designed around the concepts and application skills in the CBSE Class XII Physics 2026–27 Chapter 1 syllabus. It is not an official CBSE question paper.

Suggested test mode: Give yourself 35–40 minutes. Attempt all questions before opening the answer key. For numericals, write the formula, substitution, unit and final answer.

Section A — Multiple Choice Questions

Questions 1–15: Choose the most appropriate option.

Question 1

Two point charges are separated by distance r. If the distance is increased to 3r, the electrostatic force becomes:

(A) F/3 (B) F/6 (C) F/9 (D) 9F

Question 2

The SI unit of electric dipole moment is:

(A) C/m (B) C m (C) N/C (D) N m

Question 3

At the midpoint of two identical positive point charges, the electric field is:

(A) maximum (B) zero (C) infinite (D) directed towards either charge

Question 4

The electric field due to a point charge varies with distance r as:

(A) 1/r (B) 1/r² (C) 1/r³ (D) r²

Question 5

The direction of electric dipole moment is:

(A) positive to negative charge (B) negative to positive charge (C) perpendicular to the dipole axis (D) always opposite to the electric field

Question 6

Electric flux through a plane surface is maximum when the electric field is:

(A) parallel to the surface (B) perpendicular to the surface (C) at 45° to the surface (D) zero

Question 7

A closed surface encloses zero net charge. The net electric flux through the surface is:

(A) always positive (B) always negative (C) zero (D) infinite

Question 8

The electric field due to an ideal infinite uniformly charged plane sheet is:

(A) proportional to r (B) proportional to 1/r (C) proportional to 1/r² (D) independent of distance from the sheet

Question 9

Inside a uniformly charged thin spherical shell, the electric field is:

(A) zero (B) proportional to r (C) proportional to 1/r (D) proportional to 1/r²

Question 10

The torque on a dipole of moment p in a uniform field E is maximum when the angle between p and E is:

(A) 0° (B) 30° (C) 60° (D) 90°

Question 11

Which statement about electrostatic field lines is correct?

(A) They can intersect at a point.

(B) They form closed loops in electrostatics.

(C) Their tangent gives the field direction at a point.

(D) They always have uniform spacing.

Question 12

A charge q is placed in an electric field E. The force on it is:

(A) q/E (B) E/q (C) qE (D) q + E

Question 13

For an ideal dipole at a large distance r, the magnitude of the electric field on its axial line varies approximately as:

(A) 1/r (B) 1/r² (C) 1/r³ (D) r²

Question 14

For a closed Gaussian surface, Gauss's law is:

(A) ∮E·dA = q_enclosed/ε₀

(B) ∮E·dA = q_outside/ε₀

(C) ∮E·dA = E/A

(D) ∮E·dA = q_enclosedε₀

Question 15

Two equal and opposite charges form a dipole. At the midpoint, the electric fields due to the two charges are:

(A) equal and opposite (B) equal and in the same direction (C) unequal and opposite (D) both zero

Section B — Numerical and Application Questions

Question 16

Two point charges +2 μC and +3 μC are separated by 0.30 m in vacuum. Calculate the magnitude of the electrostatic force between them. Take k = 9 × 10⁹ N m² C⁻².

Question 17

A point charge of 4 μC is placed in vacuum. Find the magnitude of the electric field at a distance of 0.20 m from it. Take k = 9 × 10⁹ N m² C⁻².

Question 18

A uniform electric field of magnitude 5 × 10³ N/C passes normally through a plane surface of area 0.20 m². Calculate the electric flux through the surface.

Question 19

A dipole has dipole moment 4 × 10⁻⁸ C m and is placed in a uniform electric field of 3 × 10⁴ N/C at 30°. Find the magnitude of the torque.

Question 20

An infinitely long straight wire has uniform linear charge density λ = 2 × 10⁻⁸ C/m. Find the electric field at a distance of 0.10 m from the wire. Take ε₀ = 8.85 × 10⁻¹² C² N⁻¹ m⁻².

Section C — Concept and Reasoning

Question 21

Explain why the electric field at the midpoint between two equal positive charges is zero, while the electric field at the midpoint between equal and opposite charges is non-zero.

Question 22

Why can the net electric flux through a closed surface be zero even when the electric field is non-zero at many points on the surface?

Question 23

State why a spherical Gaussian surface is especially convenient for finding the field of a uniformly charged spherical shell.

Question 24

What is the physical significance of the negative sign in the statement that the electric field of a negative point charge is directed towards the charge?

Question 25

Differentiate between electric field and electric flux in terms of their nature, SI units and basic mathematical expressions.

Answer Key — Section A

Q	Ans.	Q	Ans.	Q	Ans.
1	C	6	B	11	C
2	B	7	C	12	C
3	B	8	D	13	C
4	B	9	A	14	A
5	B	10	D	15	B

Numerical Answers

Q16: F = k|q₁q₂|/r² = 0.60 N. The force is repulsive.

Q17: E = kq/r² = 9.0 × 10⁵ N/C, directed radially outward.

Q18: Φ = EA = 1.0 × 10³ N m²/C.

Q19: τ = pE sin 30° = 6.0 × 10⁻⁴ N m.

Q20: E = λ/(2πε₀r) ≈ 3.60 × 10³ N/C, directed radially outward for positive λ.

Concept Answers

Q21 — Equal Like vs Unlike Charges

For two equal positive charges, the fields at the midpoint have equal magnitude and opposite directions, so they cancel. For equal and opposite charges, the two fields at the midpoint point in the same direction—from the positive charge towards the negative charge—so they add.

Q22 — Zero Net Flux Does Not Mean Zero Field

Gauss's law states that net flux through a closed surface depends on the net enclosed charge. Positive and negative contributions to the surface integral can cancel even when the electric field is non-zero at individual points on the surface.

Q23 — Why Spherical Symmetry Helps

For a uniformly charged spherical shell, spherical symmetry makes the electric-field magnitude the same at every point on a spherical Gaussian surface of fixed radius. This allows E to be taken outside the flux integral.

Q24 — Direction for a Negative Charge

The electric field direction is defined as the direction of force on a positive test charge. A negative source charge attracts a positive test charge, so its field points towards the source charge.

Q25 — Electric Field vs Electric Flux

Feature	Electric Field	Electric Flux
Nature	Vector	Scalar
Basic expression	E = F/q₀	Φ = ∫E·dA
SI unit	N/C	N m²/C

Self-Assessment

22–25 correct: Recheck only the concepts you missed and then attempt the chapter PYQ page again.
18–21 correct: Revise the Formula Sheet and Quick Revision page before retaking the test.
13–17 correct: Revisit Notes, Important Questions and Numericals, then retake this test.
0–12 correct: Rebuild the chapter from the Notes first and use the test as a second-round assessment.

Chapter Resource Path

Use the complete Electric Charges and Fields learning path:

Curriculum basis: CBSE Class XII Physics 2026–27, Unit I: Electrostatics, Chapter 1: Electric Charges and Fields. The official syllabus covers electric charge, Coulomb's law, forces between multiple charges, superposition and continuous charge distribution, electric field, electric dipole, electric flux and Gauss's theorem with its standard applications.

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