Karnataka 2nd PUC Physics Chapter 2 Important Questions: Electrostatic Potential and Capacitance

The Karnataka 2nd PUC Physics Chapter 2 Important Questions are based on the Electric Potential and Capacitance material provided by the Government of Karnataka, Department of School Education (Pre-University). The PDF contains chapter-wise multiple-choice questions for competitive exams along with a synopsis, solved examples, practice questions, and Karnataka CET previous-year questions.

The chapter covers concepts such as electrostatic potential, potential due to point charges and dipoles, potential difference, equipotential surfaces, potential energy, electrostatics of conductors, polarisation, capacitance, combinations of capacitors, and energy stored in capacitors.

Students can use these questions to revise formulas and practise the types of numerical and conceptual problems included in the source material.

2nd PUC Physics Chapter 2 Important Questions

The following questions are selected from the practice and previous-year question sections of the provided material. They cover different concepts from Electrostatic Potential and Capacitance.

1. What is electrostatic potential?

Electrostatic potential at a point is defined as the work done in bringing a unit positive test charge from infinity to that point in an external electrostatic field.

The relation given in the material is:

V = W∞→P / q₀

The SI unit of electrostatic potential is the volt, and electrostatic potential is a scalar quantity.

2. What is the electrostatic potential due to a point charge?

For a point charge q at a distance r, the potential is:

V = 1/(4πε₀) × q/r

The potential is positive for a positive point charge and negative for a negative point charge.

A related practice question in the PDF asks how the potential changes when the magnitude of a point charge is doubled, and its distance from the point is quadrupled. Since V ∝ q/r, the new potential becomes half of the original potential.

3. How does electric potential differ from electric field?

Electric field is a vector quantity, whereas electric potential is a scalar quantity.

For a point charge:

E ∝ q/r²

while

V ∝ q/r

The material also relates electric field to force per unit charge and electric potential to work done per unit charge.

4. What is the potential due to a system of point charges?

The total electrostatic potential due to several point charges is obtained using the principle of superposition:

V = 1/(4πε₀) Σ(qᵢ/rᵢ)

The potential contributions from individual charges are added algebraically because potential is a scalar quantity.

5. What is the potential due to an electric dipole?

For a point at a large distance compared with the dipole length, the potential due to a dipole is:

V = 1/(4πε₀) × p cosθ/r²

Here, p is the dipole moment, r is the distance from the midpoint of the dipole, and θ is the angle between the dipole moment and the line joining the point to the midpoint. The expression applies when r >> 2a.

On the equatorial plane, where θ = 90°, the potential is zero.

6. What is the potential due to a charged spherical conductor?

For a charged spherical shell of radius R and charge Q, the potential inside the shell is constant:

V = 1/(4πε₀) × Q/R

For a point outside the spherical conductor:

V = 1/(4πε₀) × Q/r

These expressions are important for questions involving the potential at the centre, surface, or outside a charged sphere.

7. What is potential difference?

The potential difference between two points A and B is related to the work done in moving a test charge from B to A:

Vₐ − Vᵦ = Wᵦ→ₐ/q₀

The work done can also be written as:

Wᵦ→ₐ = q₀(Vₐ − Vᵦ)

These relations are used in several numerical questions from the material.

8. What are equipotential surfaces?

Equipotential surfaces are imaginary or real surfaces on which the potential is the same at every point.

Important properties given in the PDF include:

• The electric field is perpendicular to an equipotential surface.

• Work done in moving a charge between two points on the same equipotential surface is zero.

• Two equipotential surfaces cannot intersect.

• The electric field points in the direction of the steepest decrease of potential.

These concepts are directly tested through several MCQs in the practice section.

9. How is electric field related to potential?

The electric field and potential are related by:

E⃗ = −∇V

For variation only along the x-axis:

Eₓ = −dV/dx

For example, the material gives:

V = 2x² + 3x + 1

and asks for the magnitude of the electric field at x = 1 m. Differentiating the potential gives:

E = −(4x + 3)

At x = 1 m, the magnitude is 7 V m⁻¹.

10. What is the potential energy of a system of charges?

For three point charges in the absence of an external electric field, the potential energy is:

U = 1/(4πε₀) [q₁q₂/r₁₂ + q₂q₃/r₂₃ + q₁q₃/r₁₃]

For two charges:

U = 1/(4πε₀) × q₁q₂/r

Questions involving the change in separation between charges can be solved using these relations.

11. What is the potential energy of a dipole in a uniform electric field?

For a dipole of moment p placed in a uniform electric field E, the potential energy is:

U = −p⃗ ·E⃗ = −pE cosθ

The material gives three important cases:

• At θ = 0°, U = −pE and the dipole is in stable equilibrium.

• At θ = 90°, U = 0 and there is no equilibrium.

• At θ = 180°, U = pE and the dipole is in unstable equilibrium.

12. What are the important properties of a charged conductor?

Under electrostatic conditions:

• The electric field inside a conductor is zero.

• The electric field at the surface is normal to the surface.

• There is no excess charge inside the conductor.

• The potential remains constant throughout the conductor and on its surface.

• The electric field at the surface is E⃗ = σ/ε₀ n̂.

The practice section includes questions on the electric field and potential inside charged conducting spheres and on charge distribution over conductors.

13. What are polar and non-polar molecules?

Molecules whose positive and negative charge centres do not coincide are called polar molecules. The PDF gives HCl and H₂O as examples.

In non-polar molecules, the positive and negative charge centres coincide. The examples given are CO₂ and H₂.

For an isotropic dielectric, polarisation is related to electric field as:

P⃗ = χₑε₀E⃗

where χₑ is electric susceptibility. The SI unit of polarisation is C/m².

14. What is capacitance?

The capacitance of a conductor is defined as:

C = Q/V

where Q is the charge on the conductor and V is its potential relative to infinity.

The SI unit of capacitance is the farad (F).

For an isolated spherical conductor of radius R:

C = 4πε₀R

For a parallel plate air capacitor:

C = ε₀A/d

where A is the plate area and d is the separation between the plates.

15. How are capacitors connected in series?

For capacitors C₁, C₂, C₃, ... Cₙ connected in series:

1/Cₛ = 1/C₁ + 1/C₂ + 1/C₃ + ... + 1/Cₙ

For two capacitors:

Cₛ = C₁C₂/(C₁ + C₂)

If n identical capacitors, each of capacitance C, are connected in series:

Cₛ = C/n.

16. How are capacitors connected in parallel?

For capacitors connected in parallel:

Cₚ = C₁ + C₂ + C₃ + ... + Cₙ

For n identical capacitors:

Cₚ = nC

The material also gives the charge distribution for two capacitors connected in parallel:

Q₁ = C₁/(C₁ + C₂) × Q

and

Q₂ = C₂/(C₁ + C₂) × Q.

Here are some direct-answer questions from the practice material for quick revision:

Q17. Four point charges of +10 μC, −5 μC, +10 μC and −5 μC are placed at positions 1, 3, 7 and 9 of a clock. What are the electric field and potential at the centre?

Answer: E = 0, V ≠ 0.

Q18. What are the electric field and potential on the equatorial plane of an electric dipole?

Answer: E ≠ 0, V = 0.

Q19. A charge is moved from one point to another over an equipotential surface. What is the work done?

Answer: Zero.

Q20. Which statement correctly describes an equipotential surface?

Answer: It is a surface where the potential remains constant at every point.

Electrostatic Potential and Capacitance Important Questions PDF

The  2nd PUC Physics Chapter 2 Important Questions with Answers PDF contains a dedicated Practice Questions – Electric Potential and Capacitance section followed by a KCET Previous Year Questions (2020–2026) section. The practice section includes questions on electric potential, electric field, dipoles, conductors, polarisation, capacitance, dielectric materials, capacitor combinations, and energy stored in capacitors.

The previous-year section also includes questions on capacitor combinations, equipotential surfaces, dipoles, dielectric slabs, potential difference, charged conductors, electric susceptibility, and capacitor energy. This makes the PDF useful for practising both conceptual and numerical problems from the chapter.

Students preparing for the Karnataka 2nd PUC examination can also use the Karnataka 2nd PUC Previous Year Question Paper and Karnataka 2nd PUC Exam Pattern 2027 resources alongside chapter-wise practice.

Electrostatic Potential and Capacitance Numericals

Numerical practice is an important part of this chapter because many questions require direct application of formulas.

Focus on these formula-based areas from the PDF:

• Potential due to a point charge: V = 1/(4πε₀) × q/r

• Potential due to multiple charges: V = 1/(4πε₀) Σ(qᵢ/rᵢ)

• Potential difference: Vₐ − Vᵦ = W/q₀

• Potential energy of two charges: U = 1/(4πε₀) × q₁q₂/r

• Dipole potential energy: U = −pE cosθ

• Capacitance of a parallel plate capacitor: C = ε₀A/d

• Series combination: 1/Cₛ = Σ(1/Cᵢ)

• Parallel combination: Cₚ = ΣCᵢ

• Energy stored: U = ½CV²

• Energy density: uₑ = ½ε₀E²

For example, the PDF includes a numerical in which an air parallel plate capacitor has a plate area of 2 cm², plate separation of 2 mm, and is charged to 10 V. The question asks for the energy stored and energy density.

2nd PUC Physics Chapter 2 Important Questions with Answers

While revising this chapter, pay attention to questions that combine two or more concepts. Questions involving the relationship between E and V, changes in potential energy, equipotential surfaces, dielectric insertion, and capacitor combinations require careful reading of the given conditions.

A few areas that deserve repeated practice are:

• Potential due to point charges

• Potential due to an electric dipole

• Potential at the centre or outside a charged sphere

• Work done and potential difference

• Properties of equipotential surfaces

• Relation between electric field and potential

• Potential energy of charge systems

• Dipole potential energy and equilibrium

• Electrostatic properties of conductors

• Polarisation and electric susceptibility

• Parallel plate capacitor

• Series and parallel combinations

• Effect of changing plate separation

• Effect of inserting a dielectric

• Energy stored in capacitors

• Energy density

The material's practice section also contains questions involving graphs, assertion-reasoning, match-the-following, capacitor circuits, dielectric constants, and numerical calculations, so students should not limit revision to direct formula-based questions.

Important Resources for Karnataka 2nd PUC Physics

Students can refer to these related resources while preparing:

• Karnataka 2nd PUC Mid Term Time Table 2026 

• Karnataka 2nd PUC Mid Term Question Paper

• Karnataka 2nd PUC Previous Year Question Paper 

• Karnataka 2nd PUC Exam Pattern 2027

• Karnataka 2nd PUC Syllabus 2026-27

The Karnataka 2nd PUC Physics Chapter 2 Important Questions cover the core concepts of electric potential, potential energy, dipoles, conductors, dielectrics, capacitance, and capacitor energy. The provided Karnataka material combines conceptual MCQs with numerical and previous-year KCET questions, allowing students to practise different question formats from the chapter.

Before solving questions, revise the formulas and understand the conditions given in each problem. In particular, keep track of whether a capacitor is connected to a battery or isolated, as this changes how charge, potential difference, capacitance, and energy behave.

PW provides Karnataka 2nd PUC exam content, including Karnataka Board Exam Blogs, sample papers, mock tests, guidance sessions, and more. Also, enroll today in Karnataka 2nd PUC Online Coaching to prepare.