Table of Contents
Charging of Insulators

Since charge cannot flow through insulators, neither conduction nor induction can be used to charge, insulators, so in order to charge an insulator friction is used. Whenever an insulator is rubbed against a body exchange of electrons takes place between the two. This results in appearance of equal and opposite charges on the insulator and the other body. Thus the insulator is charged.
For example rubbing of plastic with fur, silk with glass causes charging of these things.
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COULOMB’S LAW
Last modified on:3 years agoReading Time:18MinutesCOULOMB’S LAW: Two point electric charges q1 and q2 at rest, separated by a distance r exert a force on each other whose magnitude is given by If between the two charges there is free space then Where ε0 is the absolute electric permittivity of the free space and ε0 =…
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If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why?
Last modified on:4 years agoReading Time:2Minutes If we comb our hair on a dry day and bring the comb near small pieces of paper, the comb attracts the pieces, why? Answer: This is an example of frictional electricity and induction. When we comb our hair, it gets positively charged by rubbing. When the comb is brought…
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Can two similarly charged bodies attract each other?
Last modified on:4 years agoReading Time:1Minute Yes, when the charge on one body Q is much greater than that on the other q and they are close enough to each other so that force of attraction between Q and induced charge on the other exceeds the force of repulsion between Q and q. However, two similar…
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Laws of Motion (Study Notes)
Last modified on:5 years agoReading Time:29MinutesTopics to be covered Force and inertia, Newton’s first law of motion; Momentum, Newton’s second law of motion, Impulse; Newton’s third law of motion; Law of conservation of linear momentum and its applications; Equilibrium of concurrent forces; Static and kinetic friction, laws of friction, rolling friction, lubrication; Examples of variable mass situation. Dynamics of uniform…
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FRICTION (STUDY NOTES)
Last modified on:5 years agoReading Time:7MinutesFriction Introduction If we slide or try to slide a body over a surface the motion is resisted by a bonding between the body and the surface. This resistance is represented by a single force and is called friction. The force of friction is parallel to the surface and opposite to the direction…
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Important Questions (Management of Natural Resources)
Last modified on:8 years agoReading Time:36MinutesVERY SHORT ANSWER TYPE QUESTIONS (1 Mark) Q1. What is a natural resource? Ans.: All the material we obtain from nature and use it is called natural resource. Q2. Name two important natural resources. Ans.: Forest, Water, Wildlife. Q3. What are 3 R’s used to save environment? Ans. Reduce, Recycle and…
