Details
Electric charges and fields, NCERT. electric field. page no. 18.
Details
Electric charges and fields, NCERT. electric field. page no. 18.
Comment
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.