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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IIT Foundation Mathematics Problems on Area and Perimeter
Last modified on:5 years agoReading Time:6MinutesQ.1. If the sides of a triangle are 3 cm, 4 cm and 5 cm, then what is the radius of the circum-circle? Answer Answer: 2.5 cm Q.2. If the length of hypotenuse of a right angled triangle is 5 cm and its area is 6 sq cm, then what are…
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IIT Foundation Mathematics Problems on Permutation and Combination
Last modified on:5 years agoReading Time:4MinutesQ.1. Each section in first year of plus two course has exactly 30 students. If there are 3 sections, in how many ways can a set of 3 student representatives be selected from each section? Answer Answer: 27000 Q.2. How many numbers are there between 100 and 1000 such that every…
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IIT Foundation Mathematics Problems on Probability
Last modified on:5 years agoReading Time:4MinutesQ.1. If two coins are tossed once, what is the probability of getting at least one head ? Answer Answer: 3/4 Q.2. Two unbiased dice are rolled. Find the probability of getting a multiple of 2 on one die and a multiple of 3 on the other die ? Answer Answer:…
