Karnataka 2nd PUC Physics Chapter 1 Important Questions: Electric Charges and Fields

Karnataka 2nd PUC Physics Chapter 1 Important Questions: Electric Charges and Fields are useful for students preparing for the Karnataka 2nd PUC Physics examination and competitive entrance tests. The chapter covers important concepts such as electric charge, charging methods, Coulomb’s law, electric field, electric field lines, electric dipole, electric flux and Gauss’s law.

The Karnataka Government Department of School Education (Pre-University) has provided chapter-wise Physics CET material containing practice and previous-year questions from the Electric Charges and Fields chapter. Students can use these questions to revise concepts, practise numerical problems and improve their understanding of important applications.

Important Topics in Electric Charges and Fields

Students should focus on the following topics while preparing for Chapter 1:

• Electric charge and its properties

• Quantisation and conservation of charge

• Methods of charging

• Coulomb’s law

• Electric field and electric field intensity

• Electric field due to point charges

• Principle of superposition

• Electric field lines

• Electric dipole and dipole moment

• Electric field due to an electric dipole

• Torque on an electric dipole

• Electric flux

• Gauss’s law

• Applications of Gauss’s law

• Electric field due to uniformly charged conductors

• Electric field due to an infinitely long charged wire

Karnataka 2nd PUC Physics Chapter 1 Important Questions

The following questions are taken from the uploaded Electric Charges and Fields chapter material. The options, answers and solutions have been removed so that students can use them for independent practice.

1. When a soap bubble is charged, what happens to its radius?

2. The electric field lines on the left have twice the separation on those on the right, as shown in the figure. If the magnitude of the field at A is 40 V/m, what is the force on a 20 μC charge kept at B?

3. An infinitely long thin straight wire has a uniform charge density of 1/4 × 10⁻² C m⁻¹. What is the magnitude of the electric field at a distance of 20 cm from the axis of the wire?

4. A point charge ‘q’ is placed at the corner of a cube of side ‘a’ as shown in the figure. What is the electric flux through the face ABCD?

5. The electric field due to an infinite, straight, uniformly charged wire varies with distance ‘r’ as?

6. A 2-gram object, located in a region of uniform electric field E⃗ = (300 N C⁻¹)î carries a charge Q. The object released from rest at x = 0 has kinetic energy of 0.12 J at x = 0.5 m. Then Q is?

7. A copper rod AB of length L is rotated about end A with a constant angular velocity ω. The electric field at a distance x from the axis of rotation is?

8. Which of the following statements is false in the case of polar molecules?

9. An electric dipole with dipole moment 4 × 10⁻⁹ C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 10⁴ N C⁻¹. The magnitude of the torque acting on the dipole is?

10. A positively charged glass rod is brought near an uncharged metal sphere, which is mounted on an insulated stand. If the glass rod is removed, the net charge on the metal sphere is?

11. A cubical Gaussian surface has side of length a = 10 cm. Electric field lines are parallel to the x-axis as shown. The magnitudes of electric fields through surfaces ABCD and EFGH are 6 kN C⁻¹ and 9 kN C⁻¹, respectively. Then, the total charge enclosed by the cube is?

12. Electric field at a point at distance ‘r’ from an infinitely long, uniformly charged straight conductor having linear charge density λ is E₁. Another uniformly charged conductor having the same linear charge density λ is bent into a semicircle of radius ‘r’. The electric field at its centre is E₂. Then?

13. In the situation shown in the diagram, the magnitude of q ≪ |Q| and r ≫ a. The net force on the free charge –q and net torque on it about O at the instant shown are, respectively [p = 2aQ is the dipole moment].

14. A body has a charge of −3.2 μC. The number of excess electrons it has is?

15. A point charge A of +10 μC and another point charge B of +20 μC are kept 1 m apart in free space. The electrostatic force on A due to B is F⃗₁ and the electrostatic force on B due to A is F⃗₂. Then?

16. A uniform electric field E = 3 × 10⁵ N C⁻¹ is acting along the positive Y-axis. The electric flux through a rectangle of area 10 cm × 30 cm whose plane is parallel to the Z-X plane is?

17. The total electric flux through a closed spherical surface of radius r enclosing an electric dipole of dipole moment 2aq is?

18. A metallic sphere of radius R carrying a charge q is kept at a certain distance from another metallic sphere of radius R/4 carrying a charge Q. What is the electric flux at any point inside the metallic sphere of radius R due to the sphere of radius R/4?

19. You are given a dipole of charge +q and −q separated by a distance of 2R. A sphere of radius R passes through the centre of the dipole, and sphere B of radius 2R passes through the charge +q. Then the electric flux through sphere A is?

20. Charges are uniformly spread on the surface of a conducting sphere. The electric field from the centre of the sphere to a point outside the sphere varies with distance r from the centre as?

Karnataka 2nd PUC Physics Chapter 1 Important Questions PDF Download

Students can use the Karnataka 2nd PUC Physics Chapter 1 Important Questions PDF to practise Electric Charges and Fields effectively. 

 The PDF includes questions covering electric charge, Coulomb’s law, electric field, electric dipole, electric flux and Gauss’s law. Solving these questions can help students strengthen conceptual understanding, practise numerical problems and improve their overall Physics exam preparation. 

How to Prepare Electric Charges and Fields

Students can follow a systematic approach to prepare Chapter 1 effectively:

1. Understand the Basic Concepts

Begin with the fundamental properties of electric charge. Revise the additive, conserved and quantised nature of charge. Also understand the difference between positive and negative charges.

2. Revise Important Formulas

Make a separate formula sheet covering Coulomb’s law, electric field, electric flux, dipole moment, torque and Gauss’s law. Revising formulas regularly can make numerical problem-solving easier.

3. Practise Numerical Problems

Questions involving charge, electric field, electric flux and force require careful substitution of values. Practise problems with different units and convert quantities into SI units before solving.

4. Focus on Gauss’s Law

Gauss’s law is an important part of the chapter. Students should understand electric flux and the relationship between enclosed charge and flux through a closed surface.

Karnataka 2nd PUC Physics Chapter 1 Important Questions: Electric Charges and Fields provide useful practice for important electrostatics concepts. 

Students should revise charge, Coulomb’s law, electric fields, dipoles, electric flux and Gauss’s law along with numerical problems. Regular practice of these questions can help improve conceptual clarity, calculation skills and exam preparation.

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