Introduction
Electrostatics is an important chapter of Class 10 Physics that explains the study of electric charges at rest and the forces acting between them. This chapter introduces students to fundamental concepts such as electric charge, types of charges, charging methods, Coulomb’s law, electric fields, electric potential, and capacitance. Understanding electrostatics provides the foundation for studying electricity, electronics, and many modern technologies.
Students learn how objects become charged through friction, conduction, and induction, and how charged objects interact with each other. The chapter also explains how electric fields represent the influence of charges and how capacitors store electrical energy for use in electronic circuits. Practical applications of electrostatics, including photocopiers, electrostatic painting, and electrical safety through earthing, demonstrate the importance of these concepts in everyday life.
On this page, you will find carefully selected Class 10 Physics Chapter 4 Electrostatics MCQs with answers and explanations, along with learning outcomes, quick revision notes, important definitions, formulas, exam tips, and common mistakes to help you prepare effectively for school and board examinations.
Learning Outcomes
After studying this chapter, students will be able to:
- Define electric charge and explain its properties.
- Differentiate between positive and negative charges.
- Explain methods of charging objects.
- Understand and apply Coulomb’s law.
- Describe electric fields and electric field lines.
- Explain electric potential and potential difference.
- Understand capacitance and the function of capacitors.
- Identify practical applications of electrostatics.
Quick Notes – Chapter Summary
- Electrostatics deals with electric charges at rest.
- There are two types of charges: positive and negative.
- Like charges repel, while unlike charges attract each other.
- Objects can be charged by friction, conduction, and induction.
- Coulomb’s law describes the force between two electric charges.
- Electrostatic force depends on the magnitude of charges and distance between them.
- An electric field is the region where a charge experiences an electric force.
- Electric field lines move outward from positive charges and inward toward negative charges.
- Electric potential represents work done per unit charge.
- Capacitors are devices used to store electric charge.
- Capacitance depends on plate area, distance between plates, and dielectric material.
- Earthing protects objects by transferring excess charge safely to the ground.
Important Definitions
Electrostatics: The branch of Physics that deals with electric charges at rest.
Electric Charge: A physical property of matter responsible for electric forces.
Electric Field: The region around a charge where another charge experiences a force.
Electric Field Lines: Imaginary lines used to represent the direction and strength of an electric field.
Coulomb’s Law: A law that describes the electrostatic force between two point charges.
Electric Potential: The work done per unit charge in bringing a charge to a point.
Capacitor: A device used to store electric charge and electrical energy.
Capacitance: The ability of a capacitor to store electric charge.
Dielectric: An insulating material placed between capacitor plates to increase capacitance.
Earthing: The process of transferring excess electric charge safely into the Earth.
Important Formulas
Coulomb’s Law => F = k(q₁q₂) / r²
Where:
- F = Electrostatic force
- q₁ and q₂ = Charges
- r = Distance between charges
- k = Coulomb constant
Electric Field Strength => E = F / q
Where:
- E = Electric field
- F = Force
- q = Charge
Electric Potential => V = W / q
Where:
- V = Electric potential
- W = Work done
- q = Charge
Capacitance => C = Q / V
Where:
- C = Capacitance
- Q = Charge stored
- V = Potential difference
Class 10 Physics Chapter 4 – Electrostatics MCQs
1. The SI unit of electric charge is:
- A. Coulomb ✅
- B. Volt
- C. Ampere
- D. Ohm
Explanation: The coulomb (C) is the standard SI unit of electric charge.
2. Like charges:
- A. Attract each other
- B. Repel each other ✅
- C. Have no effect on each other
- D. Neutralize each other
Explanation: According to electrostatic principles, like charges repel while unlike charges attract.
3. Coulomb’s law states that the electrostatic force is directly proportional to:
- A. Product of charges ✅
- B. Sum of charges
- C. Difference of charges
- D. Square of charges
Explanation: F ∝ q₁ × q₂ and inversely proportional to the square of the distance between them.
4. The medium between two charges affects the force between them because of:
- A. Its density
- B. Its permittivity ✅
- C. Its temperature
- D. Its pressure
Explanation: The permittivity of a medium determines how much it reduces the electrostatic force compared to vacuum.
5. The region around a charged object where other charges feel a force is called:
- A. Magnetic field
- B. Electric field ✅
- C. Potential difference
- D. Capacitance
Explanation: An electric field exists around a charged body and exerts force on other charges within it.
6. The electric field lines for a positive charge point:
- A. Radially outward ✅
- B. Radially inward
- C. Circular around the charge
- D. Tangential to the surface
Explanation: Field lines originate from positive charges and terminate on negative charges.
7. Which of the following is used to store electric charge?
- A. Resistor
- B. Capacitor ✅
- C. Transformer
- D. Inductor
Explanation: Capacitors store electric charge and release it when needed in a circuit.
8. The unit of capacitance is:
- A. Volt
- B. Coulomb
- C. Farad ✅
- D. Ohm
Explanation: Capacitance is measured in farads (F), defined as 1 coulomb per volt.
9. In photocopiers, the electrostatic principle used is:
- A. Electromagnetic induction
- B. Attraction of toner particles to charged areas ✅
- C. Total internal reflection
- D. Diffraction
Explanation: Toner particles are charged and stick to oppositely charged areas of the drum to form images.
10. Which factor does NOT affect the capacitance of a parallel plate capacitor?
- A. Plate area
- B. Distance between plates
- C. Voltage applied ✅
- D. Dielectric constant
Explanation: Capacitance depends on geometry and dielectric material, not on applied voltage.
11. If two charges of +2 μC and -2 μC are separated, the force between them is:
- A. Repulsive
- B. Attractive ✅
- C. Zero
- D. Neutral
Explanation: Opposite charges always attract each other.
12. Which instrument is used to detect small electric charges?
- A. Ammeter
- B. Gold-leaf electroscope ✅
- C. Voltmeter
- D. Multimeter
Explanation: A gold-leaf electroscope is sensitive to small electric charges and indicates them by leaf divergence.
13. Which of these materials is a good insulator?
- A. Copper
- B. Rubber ✅
- C. Aluminum
- D. Iron
Explanation: Rubber does not allow free movement of charges, making it a good electrical insulator.
14. The process of transferring charge from one object to another by direct contact is called:
- A. Conduction ✅
- B. Induction
- C. Polarization
- D. Discharge
Explanation: In conduction, charges are transferred through direct contact between conductors.
15. Which dielectric material is commonly used in capacitors?
- A. Copper
- B. Mica ✅
- C. Iron
- D. Steel
Explanation: Mica is a good dielectric with high insulation strength, used in certain types of capacitors.
16. The total electric charge in an isolated system:
- A. Continuously increases
- B. Continuously decreases
- C. Remains constant ✅
- D. Becomes zero always
Explanation: According to the law of conservation of charge, the total electric charge in an isolated system remains constant.
17. Increasing the dielectric constant between the plates of a capacitor will:
- A. Decrease capacitance
- B. Increase capacitance ✅
- C. Destroy the capacitor
- D. Remove all charge
Explanation: A dielectric material increases the ability of a capacitor to store electric charge, increasing its capacitance.
18. Electric potential difference is defined as:
- A. Charge flowing per second
- B. Force acting per unit charge
- C. Work done per unit charge ✅
- D. Resistance offered to current
Explanation: Potential difference is the work done in moving a unit charge between two points in an electric field.
19. Lightning is an example of:
- A. Magnetic induction
- B. Chemical reaction
- C. Electrostatic discharge ✅
- D. Nuclear reaction
Explanation: Lightning occurs due to the sudden discharge of accumulated electric charges between clouds or between clouds and Earth.
20. A capacitor stores energy in the form of:
- A. Chemical energy
- B. Mechanical energy
- C. Magnetic energy
- D. Electric field energy ✅
Explanation: A capacitor stores electrical energy in the electric field formed between its plates.
Exam Tips
- Memorize Coulomb’s law and capacitance formulas.
- Understand the difference between conductors and insulators.
- Learn the directions of electric field lines around charges.
- Remember the three methods of charging objects.
- Practice numerical problems involving force, charge, and distance.
Common Mistakes
❌ Confusing positive and negative charge interactions.
❌ Forgetting that electric field lines move away from positive charges.
❌ Mixing up electric field and electric potential.
❌ Assuming capacitance depends on applied voltage.
❌ Confusing charging by conduction with charging by induction.
Conclusion
Electrostatics explains the behaviour of electric charges at rest and the forces produced between them. Concepts such as Coulomb’s law, electric fields, electric potential, and capacitance are essential for understanding electricity and electronic devices. Learning these principles helps students understand both theoretical Physics and practical applications such as capacitors, photocopiers, and electrostatic technologies. Regular practice of MCQs, formulas, and important concepts will improve understanding and help students achieve better results in school and board examinations.