Electrical Field
A positive charge or a negative charge is said to create its field around itself.
If a charge
Thus space around a charge in which another charged particle experiences a force is said to have electrical field in it.
(1) Electric field intensity :
The electric field intensity at any point is defined as the force experienced by a unit positive charge placed at that point.
Where
(2) Unit and Dimensional formula of Electrical Field :
It’s S.I. unit –
C.G.S. unit – Dyne/stat coulomb.
Dimension :
[
(3) Direction of electric field :
Electric field (intensity)
(4) Relation between electric force and electric field :
In an electric field
(5) Superposition of electric field (electric field at a point due to various charges) :
The resultant electric field at any point is equal to the vector sum of electric fields at that point due to various charges.
The magnitude of the resultant of two electric fields is given by
(6) Electric field due to continuous distribution of charge :
A system of closely spaced electric charges forms a continuous charge distribution
Linear charge distribution
In this distribution charge distributed on a line.
For example : charge on a wire, charge on a ring etc. Relevant parameter is
Surface charge distribution
In this distribution charge distributed on the surface.
For example : Charge on a conducting sphere, charge on a sheet etc. Relevant parameter is
Volume charge distribution
In this distribution charge distributed in the whole volume of the body.
For example : Non conducting charged sphere. Relevant parameter is
To find the field of a continuous charge distribution, we divide the charge into infinitesimal charge elements.
Each infinitesimal charge element is then considered, as a point charge and electric field
The Net field at the given point is the summation of fields of all the elements. i.e.,