⚡ Chapter 15: Electrostatics – Constructed Response Questions
Prepared by Muhammad Tayyab, Subject Specialist Physics, Govt Christian High School Daska. Based on PECTAA 2026 syllabus (National Curriculum 2023).
📖 What's Inside: This chapter covers charging by friction, electrostatic attraction, dust attraction to screens, polar nature of water, and conductors vs insulators. Each constructed response question is presented with the detailed reasoning and exam-ready answer as per the official PECTAA 2026 Physics curriculum. Perfect for Punjab Boards (Lahore, Gujranwala, Multan, etc.) and all BISE boards across Pakistan.
📚 Related Resources – Chapter 15: Electrostatics
Electrostatics covers Coulomb's law, electric field, potential, capacitance, charging by induction, electroscope, lightning, corona discharge, and applications. Includes solved examples and numerical problems.
📖 Constructed Response Questions & Answers (PECTAA 2026)
15.1 Why do some materials gain electrons while others lose electrons when rubbed together? What property of the materials determines this behaviour?
When two materials are rubbed together, electrons are transferred from one material to another. One material gains electrons and becomes negatively charged, while the other loses electrons and becomes positively charged. This behaviour depends on the ability of the materials to gain or lose electrons.
When two materials are rubbed together, electrons are transferred from one material to another. One material gains electrons and becomes negatively charged, while the other loses electrons and becomes positively charged. This behaviour depends on the ability of the materials to gain or lose electrons.
15.2 A charged comb attracts small pieces of paper, but after some time, the paper pieces fall off. Why does this happen?
The charged comb attracts the paper pieces by electrostatic force. After touching the comb, the paper pieces acquire the same type of charge as the comb. Since like charges repel, the paper pieces fall off.
The charged comb attracts the paper pieces by electrostatic force. After touching the comb, the paper pieces acquire the same type of charge as the comb. Since like charges repel, the paper pieces fall off.
15.3 Why do dust particles often get attracted to television screens or computer monitors after they are turned ON?
When a television screen or computer monitor is turned ON, electric charges accumulate on its surface. These charges attract dust particles by electrostatic force, causing them to stick to the screen.
When a television screen or computer monitor is turned ON, electric charges accumulate on its surface. These charges attract dust particles by electrostatic force, causing them to stick to the screen.
15.4 If we rub a balloon on our dry hair and place it near a thin stream of water, the water bends toward the balloon. What does this tell us about the nature of water molecules?
The charged balloon attracts the water molecules, causing the stream of water to bend. This shows that water molecules are polar and are attracted by an electric field.
The charged balloon attracts the water molecules, causing the stream of water to bend. This shows that water molecules are polar and are attracted by an electric field.
15.5 A conductor and an insulator are both placed in an electric field. How will their behaviour differ, and why?
In a conductor, free electrons move easily, so charges are redistributed. In an insulator, electrons are tightly bound and cannot move freely. Therefore, conductors allow charge to move, while insulators resist the flow of charge.
In a conductor, free electrons move easily, so charges are redistributed. In an insulator, electrons are tightly bound and cannot move freely. Therefore, conductors allow charge to move, while insulators resist the flow of charge.
📐 Key Formulas – Electrostatics
Coulomb's Law: \( F = k \frac{q_1 q_2}{r^2} \)
Electric Field Intensity: \( E = \frac{F}{q_0} \)
Electric Field (Point Charge): \( E = k \frac{q}{r^2} \)
Electric Potential: \( V = \frac{W}{q} \)
Coulomb's Constant: \( k = 9 \times 10^9 \, \text{Nm}^2\text{C}^{-2} \)
Quantization of Charge: \( q = ne \)
Unit 10Thermal Physics
Unit 11Transfer of Thermal Energy
Unit 12Waves
Unit 13Sound
Unit 14Light
Unit 15✨ Electrostatics
Unit 16Electricity
Unit 17Electromagnetism
Unit 18Electromagnetic Induction & EM Waves
Unit 19Electronics
Unit 20Atomic and Nuclear Physics
Unit 21Space and Environment
📖 Complete syllabus coverage for Class 10 Physics (PECTAA 2026) – Units 10 to 21
💡 Exam Tip:
For board exams, provide clear reasoning and explain the underlying principles. These constructed response questions follow the PECTAA 2026 pattern and are prepared by Subject Specialist Muhammad Tayyab.
Created by Hira Science Academy | Aligned with PECTAA 2026 Syllabus