Electric Charges and Fields Class 12 Physics MCQs

Electric Charges and Fields — Class 12 Physics MCQs
Chapter-wise multiple-choice practice covering electric charge, Coulomb's law, superposition, electric field, electric dipole, electric flux and Gauss's theorem.

How to Use These MCQs

Try each question before checking the answer. Pay attention to units, directions, proportionality and the conditions attached to Gauss's law applications.

1. Electric Charge

1. Which statement about electric charge is correct?

A. Electric charge can be created from nothing.

B. Electric charge is conserved in an isolated system.

C. Electric charge has no sign.

D. Electric charge is always continuous in nature.

Answer: B

2. The elementary charge is approximately:

A. 1.6 × 10⁻¹⁹ C

B. 9 × 10⁹ C

C. 8.85 × 10⁻¹² C

D. 6.67 × 10⁻¹¹ C

Answer: A

3. Quantisation of charge means that the net charge on an isolated body is:

A. Any arbitrary real number

B. Always positive

C. An integral multiple of the elementary charge

D. Always zero

Answer: C

2. Coulomb's Law

4. According to Coulomb's law, the electrostatic force between two point charges is proportional to:

A. r

B. 1/r

C. 1/r²

D. r²

Answer: C

5. If the separation between two point charges is doubled, the magnitude of their electrostatic force becomes:

A. Four times

B. Twice

C. Half

D. One-fourth

Answer: D

6. The electrostatic force between two like charges is:

A. Attractive

B. Repulsive

C. Always zero

D. Perpendicular to the line joining them

Answer: B

7. Coulomb's law is directly applicable in its elementary form to:

A. Two point charges

B. Any two extended bodies without approximation

C. Only neutral bodies

D. Only magnetic poles

Answer: A

3. Principle of Superposition

8. The principle of superposition states that the net electrostatic force on a charge is:

A. The product of all individual forces

B. The vector sum of the individual forces

C. Always equal to the largest individual force

D. The scalar sum only

Answer: B

9. At the midpoint between two identical positive charges, the electric field is:

A. Zero

B. Directed towards the first charge

C. Directed towards the second charge

D. Infinite

Answer: A

4. Electric Field

10. Electric field intensity at a point is defined as:

A. Work done per unit charge

B. Force per unit positive test charge

C. Charge per unit force

D. Energy per unit mass

Answer: B

11. The electric field due to a positive point charge is directed:

A. Radially inward

B. Radially outward

C. Tangentially

D. In a circular path

Answer: B

12. The SI unit of electric field is:

A. N/C

B. C/N

C. N·C

D. J/C²

Answer: A

13. Electric field lines start from:

A. Negative charges and end on positive charges

B. Positive charges and end on negative charges, or extend to infinity

C. Only neutral bodies

D. Magnetic poles

Answer: B

14. Two electric field lines cannot intersect because:

A. Field lines have no direction

B. Electric field at a point has a unique direction

C. Charges are always stationary

D. Field lines are physical wires

Answer: B

5. Electric Dipole

15. An electric dipole consists of:

A. Two equal positive charges

B. Two equal negative charges

C. Equal and opposite charges separated by a small distance

D. Two neutral bodies

Answer: C

16. The SI unit of electric dipole moment is:

A. C m

B. C/m

C. N/C

D. N m

Answer: A

17. The direction of electric dipole moment is from:

A. Positive charge to negative charge

B. Negative charge to positive charge

C. Centre to negative charge

D. Centre to positive charge only

Answer: B

18. The torque on an electric dipole in a uniform electric field is maximum when the angle between p and E is:

A. 0°

B. 30°

C. 90°

D. 180°

Answer: C

6. Electric Flux

19. Electric flux through a plane surface in a uniform electric field is given by:

A. EA sin θ

B. EA cos θ

C. E/A

D. A/E

Answer: B

20. Electric flux through a 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 everywhere

Answer: B

7. Gauss's Theorem

21. Gauss's law relates the total electric flux through a closed surface to:

A. The total area of the surface only

B. The net charge enclosed by the surface

C. The distance from the nearest charge only

D. The surface temperature

Answer: B

22. The total electric flux through a closed surface enclosing charge q is:

A. qε₀

B. q/ε₀

C. ε₀/q

D. Zero for every q

Answer: B

23. A Gaussian surface encloses no net charge. The total electric flux through it is:

A. Infinite

B. q/ε₀

C. Zero

D. Dependent only on the shape

Answer: C

24. For an infinitely long uniformly charged straight wire, the magnitude of electric field varies with distance r as:

A. r

B. r²

C. 1/r

D. 1/r²

Answer: C

25. For a uniformly charged infinite plane sheet, the magnitude of the electric field is:

A. Proportional to distance from the sheet

B. Inversely proportional to distance from the sheet

C. Independent of distance from the sheet

D. Always zero

Answer: C

8. Mixed Exam-Level MCQs

26. If the magnitude of each of two charges is doubled while their separation remains unchanged, the electrostatic force becomes:

A. Half

B. Twice

C. Four times

D. One-fourth

Answer: C

27. A charge is placed at the centre of a spherical Gaussian surface. If the radius of the sphere is doubled, the total electric flux through it:

A. Becomes four times

B. Becomes twice

C. Becomes half

D. Remains unchanged

Answer: D

28. A charged thin spherical shell has zero electric field at an interior point because:

A. The shell contains no charge

B. A suitable Gaussian surface inside encloses zero net charge

C. Electric charge has no field

D. Coulomb's law is not valid

Answer: B

29. At a point on the equatorial line of an electric dipole, the electric field is directed:

A. Along the dipole moment

B. Opposite to the dipole moment

C. Perpendicular to the dipole axis only

D. Always zero

Answer: B

30. Which quantity is represented by the area under a suitable electric-field-versus-distance graph only after specifying the physical context?

A. Electric charge in every situation

B. Electric potential difference, when integrated with respect to distance along the field

C. Electric flux in every situation

D. Dipole moment in every situation

Answer: B

9. Answer Key

Q	Ans.	Q	Ans.	Q	Ans.
1	B	11	B	21	B
2	A	12	A	22	B
3	C	13	B	23	C
4	C	14	B	24	C
5	D	15	C	25	C
6	B	16	A	26	C
7	A	17	B	27	D
8	B	18	C	28	B
9	A	19	B	29	B
10	B	20	B	30	B

10. Quick Revision Targets

• Charge: conservation, quantisation and additivity.
• Coulomb's law and inverse-square dependence.
• Superposition of forces and electric fields.
• Electric field and field-line properties.
• Electric dipole, dipole moment and torque.
• Electric flux and the area vector.
• Gauss's law and its standard applications.

Curriculum basis: CBSE Class XII Physics 2026–27, Unit I: Electrostatics, Chapter 1: Electric Charges and Fields. The official curriculum covers electric charges, Coulomb's law, superposition, electric field, electric dipole, electric flux and Gauss's theorem with its listed applications. citeturn0search9