Electricity & Megnetism

Difference between electric and magnetic field

The difference between electric and magnetic field is that “Electric field is the area around the charged particles,it was introduced by Michel Faraday.While,magnetic field is the area or region around the magnetic where poles of magnet shows force of attraction or repulsion.More differences about electric field and magnetic field  are given in the comparison table below.

Electric field Vs Magnetic field

Electric field

Magnetic field

It is the force or area around the charged particle.It is the region where poles of magnet shows force of attraction or repulsion.
Its unit is Volt/meter or (N/C)Its unit is Tesla
Its symbol is “E”Its symbol is “B”
Its formula is E= F/qIts formula is  B= fi/A
It is measured by electrometerIt is measured by magnetometer
It is mono poleIt has di pole
Its field lines originates from positive charge and terminate on negative chargeIts field lines generates from north pole and terminates on south pole
Electric filed lines do not form any closed loopMagnetic field lines form a closed loop
It exist in 2 dimensionsIt remains in 3 dimensions
Electric field can do workMagnetic field cannot do work

 

What is electric field?

Coulomb’s law for the force between charges encourages us to think in terms of action at a distance represented as charge  ↔ charge.

Again introducing the field as an intermediary between the charges, we can represent the interaction as:

charge ↔  field ↔ charge

Therefore the first charge sets up an electric field, and the second charge interacts with the electric field of the first charge.Our problem of determining the interaction between the charges is therefore reduced to two separate problems:

1: Determine by measurement or calculation the electric field established by the first charge at every point in space.

2: Calculate the force that the fields exert on the second place at a particular point in space.

In analogy with the relation of the gravitational field   ( g =F/ ) We define the electric field E associated with a certain collection of charges in terms of force exerted on a positive test charge q0 at a particular point is:

E = F /q0

The direction of the vector E is the same as the direction of F , because q0 is a positive scalar.

Dimensionally the electric field is the force per unit charge.

SI Unit: Newton /Coulomb  (N/C)

Equivalent unit : Volt /meter  (V/m)

In a gravitational field, g is usually expressed in units of m/s.s and it can also be expressed as the force per unit mass in units of Newton/ Kilogram.Both the gravitational and electric fields can be expressed as a force divided by a property (mass or charge) of the test body.

What is the magnetic field?

In electrostatics, we represented the relation between electric field and electric charge symbolically by  charge   field charge

That is electric charges set up an electric field, which in turn can exert a force of electric origin on other charges. The symmetry between electric and magnetic fields by writing.

Magnetic charge ↔  magnetic field ↔magnetic charge

Which can also write as

Electric current  ↔magnetic field (B)↔ electric current

A moving electric charge or an electric current sets up a magnetic field, which can then exert a magnetic force on other moving charges or currents.

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