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The electric force was described as a noncontact force by the unit of static electricity. Actions that were performed at a distance are termed field forces. Scientists used this term to explain the phenomena of the force that occurs in the absence of physical contact. Due to the presence of any charge, the space surrounding that charge gets affected, ie, an electric field is developed in that space. So, due to the presence of the charge, the other charges feel an unusual alteration in the space. For example, a charged balloon feel an alteration due to the presence of an oppositely-charged balloon, even when they are not in direct contact.
Electric field:
Electric field results in affection on the other charges nearby, causing a force on them.
An electric force experienced per unit charge is known as the electric field. The strength of the force is directly proportional to the charge. The electric field is denoted by E.
The concept of the electric field enables us to introduce physical quantities, quantify these phenomena, associate the values with a unit and put them into equations for prediction and analysis.
The magnitude of the electric field is given by:
E=Fq
Where,
F= force experienced by the charge
and q = magnitude of charge in Coulombs
Inside a charged conductor, the electric field is negligible or zero. The reason behind this is that the charges located or placed on the conductor’s surface, oppose each other symmetrically and add up to zero in all locations.
Also, electric fields follow the superposition principle.
Superposition principle
This principle states that for all linear systems, the overall response to multiple stimuli at a given place and time is equal to the sum of the responses which would have followed from each stimulus individually.
Electric field due to a point charge:
At a distance r (in m), the electric field due to a small charge Q (in C) is given by-
E=Q4r2
where,
=permittivity of free space
The value for the permittivity of the free space is 8.8510-12Fm-1
SI unit of electric field:
The SI unit of the electric field is Newton per coulomb (NC-1)
1 Newton per coulomb is equivalent to 1 volt per metre.
1 NC-1=1 Vm-1
Dimensional formula of the electric field:
For any quantity, the dimensional formula is the expression representing the powers to which the fundamental units can be raised to get the one unit of the derived quantity.
As we know, the force of electrostatic on a charge q, placed in an electric field is shown as:
F=qE
E=Fq
[E]=[Fq]= [MLT-2AT]
= [MLT-3A-1]
where,
M=Mass
L= Length
T=Time
A= Ampere (current)
Electric field line
Scientists developed the concept of electric field lines to visualise the electric field. These are imaginary lines. As we know, an electric field is a vector quantity, so these electric field lines use the arrow to represent the direction of the electric field. Electric field lines begin from the positive (+) charge and end at the negative (-) charge or at infinity.
The more the density of the electric field lines, the more will be the strength of the electric field.
When the magnetic and the electric field lines combine, they form the electromagnetic field.
Properties of the electric field lines:
They never cross-cut each other (if they cut across each other, then there will be two directions at the point of intersection, which is impossible.)
These field lines are perpendicular to the surface charge.
These electric field lines start or end at infinity if there is only a single charge.
Types of electric fields:
The electric field can be classified into two types-
Uniform electric field.
Non-uniform electric field.
Uniform electric field:
When the magnitude of the electric field remains constant at each point, the field is termed a uniform electric field.
Method to obtain the uniform electric field: The uniform electric field can be obtained by placing two conductors parallelly. The potential difference between the conductors remains constant at every point.
Non-uniform electric field:
When the magnitude of the electric field is irregular at every point, it is referred to as a non-uniform electric field. The magnitude of the electric field is dissimilar at different points.
Conclusion
An electric field is a quantity associated with every point in the space when the charge is present in any form. A line is drawn tangent to the electric field line representing the direction of the electric field. The space is altered or affected by the presence of the charged object. If another charged object enters the space and moves deeper and deeper into the field, the field’s effect becomes more noticeable. The electric field can be considered similar to the gravitational field, involving action-at-a-distance force. Therefore electric fields are significant in many areas of physics.
