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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CBSE Class 9 Science Important Question Chapter 9 Force and Laws of Motion
Last modified on:5 years agoReading Time:12Minutes Very Short Answer Questions (1 Marks) Part-1 Q.1. State Newton’s first law of motion. Q.2. An athelete always runs some distance before taking a jump. Why? Q.3. Define 1 kg weight and express it in newton. Q.4. What is the mass of an object whose weight is 196 N? Q.5. Two similar…
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CBSE Class 9 Science Revision Notes Chapter 9 Force and Laws of Motion
Last modified on:5 years agoReading Time:8Minutes1. Force, generally denotes push or pull. 2. Force, is defined as an external agent which changes or tends to change the state of rest or uniform motion of the body or changes the direction of the body or deforms the body. 3. Effects of force :(i) A force can produce…
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Class 9 Science Work & Energy (Questions from board papers)
Last modified on:5 years agoReading Time:25MinutesScience Chapter-11 Work and Energy (Questions from Board Papers) Question 1: Identify and state the type of transformation of energy in the following cases: (a) When coal is burnt. (b) In a thermal power plant [CBSE 2014] Answer 1: (a) Chemical energy…
