Define Electric field .

Explanation

The electric field at the point P at a distance r from the point charge q is the force experienced by a unit charge and is given by
`vecE=(vecF)/(q_(0))=(kq)/(r^(2))hatr=(1)/(4piepsilon_(0))hatr `
Here `hatr ` is the unit vector pointing from q to the point of interest P. The electric field is a vector quantity and its SI unit is Newton per Coulomb `(NC^(-1))`
Important aspects of Electric field
(i) If the charge q is positive then the electric field points away from the source if q is negative the electric field point towards the source charge q.
(ii) If the electric field at a point P is `vecE ` then the force experienced by the test charge qo placed at the point P is `vecF=q_(0)vecE`. This is Coulomb.s law in terms of electric field . This is shown in the below figure .

(v) In the definition of electric field it is asumed that the test charge `q_(0)` is taken sufficiently small , so that bringing this test charge will not move the source charge . In other words the test charge is made sufficientlysmall such that it will not modify the electric field of the source charge .
(vi) The expression is valid only for point charges . For continuous and finite size charge distribution integration techniques must be used . However this expression can be used as an approximation for a finite -sized charge if the test point is very far away from the finite sized source charge .
(vii) There are two kinds of the electric field uniform (constant ) electric field and non-uniform electric field . Uniform electric field will have the same direction and constant magnitude at all points in space. Non -uniform electric field will have different directions or different magnitudes or both at different point in space . The electric field created by a point charge is basically a non- uniform electric field . This non-uniformity arise both in direction and magnitude with the direction being readially outward ( or inward ) and the magnitude changes as distance increases .