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Electric charges and fields, NCERT. electric field. page no. 18.
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Electric charges and fields, NCERT. electric field. page no. 18.
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Electric charges and fields, NCERT. electric field. page no. 18.
When a point charge Q is placed in vacuum, it exerts a force on another charge Q at point P. Scientists introduced the concept of the field to explain what happens when Q is removed. The electric field is like a ray of force emitted by Q. The formula for force is KQ1Q2/R^2, and for electric field, it is KQ/R^2. The charge Q produces an electric field everywhere in its surrounding. When another charge Q is brought to a point P1, the field at that point acts on it and produces a force. The formula for electric field is E = KQ/R^2, where K = 1/4πε0. Let us consider a point charge Q placed in vacuum. At the origin O, if we place another point charge Q at a point P, where OP is R, then the charge Q will exert a force on Q at the coulomb slot. We may ask the question, if charge Q is removed, then what is left in the surrounding? Is there nothing? If there is nothing at the point P, then how does the force act when we place the charge Q at P? In order to answer such questions, the early scientists introduced the concept of the field. We can understand it by a simple means. We know what force is, right? We know what electric force is. If I am sitting here and there is someone else sitting beside me, I am Q1 and that person is Q2. Then the force between us will be Q1 and Q2. But if only I am sitting and there is no one in the room, then I am going to emit a ray of force. That will be electric field. That will be a ray which will not land on anyone. So I am the only one left. So I am Q, just Q. So that way we can deduce the formula. In force, we will write KQ1Q2 by R2. And in electric field, because I am the only one emitting the ray, it will be KQ by R2. According to this, we say that the charge Q produces an electric field everywhere in the surrounding because it's a ray. When another charge Q is brought at some point P1, the field there acts on it and produces a force. The electric field produced by the charge Q at the point R is given as E is equal to KQ by R2, where K's value is 1 by 4 pi epsilon 0. And then 1 by 4 pi epsilon 0 into Q by R2 into R cap, where R cap is a unit vector. That way we will know in what direction the ray is going.