Name: Sources of Electromagnetic Waves
Uploaded: 2019-07-19
Duration: 5 min 12 s
Description: Can you name some sources of electromagnetic waves by looking around you? You will learn about the different sources of electromagnetic waves

Question

What does the Maxwell's equation explain?

Accepted Answer

Maxwell’s equations integral form explain how the electric charges and electric currents produce magnetic and electric fields. The equations describe how the electric field can create a magnetic field and vice versa.

First equation:-

It is nothing but the Gauss's law. It relates the net electric flux to net electric charge enclosed in a surface.

$\oint \vec{E} . \vec{d A} = \frac{Q_{e n c l o s e d}}{\in_{o}}$

Where, $E$ is electric field vector and $A$ is area vector.

This equation is true for both discrete and continuous distribution of charges.

Second equation:-

The surface integral of magnetic field over a closed surface is zero.

$\oint \vec{B} . \vec{d A} = 0$

Where, $B$ is magnetic field vector and $A$ is area vector.

This equation implies that the magnetic lines of force form a continuous closed path. It means that no isolated magnetic monopole exists.

Third equation:-

It is Faraday's law of electromagnetic induction. This law relates electric field with the changing magnetic flux.

$\oint \vec{E} . \vec{d l} = - \frac{d ϕ_{B}}{d t}$

This equation implies that the line integral of the electric field around any closed path is equal to the rate of change of magnetic flux through the closed path bounded by the surface.

Our modern technological revolution is due to Faraday's laws of electromagnetic induction.

Fourth equation:-

It is modified Ampere's circuital law. This is also known as Ampere-Maxwell's law.

This law relates the magnetic field around any closed path to the conduction current and displacement current through that path.

$\oint \vec{B} . \vec{d l} = μ_{o} i_{c} + μ_{o} \in_{o} \frac{d ϕ_{E}}{d t}$

This equation shows that both conduction and displacement current produces magnetic field. This equation ensures the existence of electromagnetic waves. These four equations are known as Maxwell's equations in electrodynamics.

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