How radio wave works

Watch videos: What is radio wave? and What is Light?

Introduction

Maxwell’s electromagnetic wave theory of light originated mostly from three phenomenons.1) When a conductor brakes a magnetic field, an electric field is created within the conductor, 2) Flowing of electrons through a conductor creates a magnetic field around that conductor, 3) Faraday effect- a magneto-optical phenomenon (the rotation of the plane of polarization by the application of a magnetic field). Maxwell has mistakenly concluded that, if an oscillating magnetic field creates an oscillating electric field in a conductor, an oscillating magnetic field should also create oscillating electric field in empty space. He has also believed that, oscillating electric field in space creates oscillating magnetic field. He has hurried with these observations and applied this in the development of his theory of light. The theory says that, light is an electromagnetic phenomenon and the perpendicularly oscillating electric and magnetic fields in space make the propagation of light.

In this article we can see that, an oscillating magnetic field can create an oscillating electric field only in a conductor and not in empty space.

When a conductor breaks a magnetic field, the magnetic field lines exert force on the free electrons in the conductor and which causes an unbalanced charges within the conductor. On the other hand, magnetic field is created when charged particles are aligned in a single mode in a material.

*Electric field and magnetic field both are created only in the presence charged particles. 

*An electron has a standing-electric field and magnetic field in right angle regardless of any kind of its motions and act as a tiny bar magnet with a negative charge (evidences for the right angle relationship between electric and magnetic field). Watch video: Structure of electron

Electric field

Electric field will be created in the below stated circumstances.

a) A charged particle (negative/positive) can create an electric field around that particle.       

b) An oscillating magnetic field can create an oscillating electric field within a conductor.

*Electric field lines hold nucleus and electrons in an atom together; atoms in a molecule are together.

*An unbalanced and opposite charges within a conductor or between two conductors cause the flow of charges through that conductor (s).

Magnetic field

Magnetic field will be created in the below stated circumstances.

A charged particle (positive/negative) has magnetic property and act as a small magnet. When charged particles are aligned in a single mode in a material, a magnetic field will be created around that material. For example, when electrons are flowing through a conductor, all electrons will be aligned in a single way. This alignment of flowing electrons create a collective magnetic field around that conductor (flowing electrons cause to align them, otherwise, there is no any direct connections between motion of electrons and magnetic field). In a permanent magnet, outer electrons of the atoms of domains are aligned in a single way and all domains are also aligned in a single way. This alignment creates a magnetic field around a permanent magnet. In the case of an iron core inside of a solenoid, the influence of the magnetic field that created by the flowing electrons in the conductor, the outer electrons of the atoms of the iron core will be aligned in a single way and causes to create a magnetic field around the core. (Watch video: Magnetic field http://www.youtube.com/watch?v=CYO-JV_Tn3U )

Oscillating magnetic field created by a radio wave transmitter (how is radio wave created?)

The flow of electrons through a conductor is caused by the attraction between electric fields of “mobile” electrons and the “fixed” positive charges in the conductor. I.e. the electrons move to the direction of positive charge. The oscillation of electrons in a conductor (radio wave transmitter) is caused by the alternation in the direction of attraction on electrons. Since the electron has electric and magnetic field in right angle, when electrons oscillate in a conductor, the oscillating magnetic lines created by the electrons is radiated to space perpendicular to their oscillations. As the drift velocity increases with the increasing of voltage, when electrons oscillate at higher voltages, a radio transmitter creates high amplitude oscillating magnetic lines. Watch video: What is radio wave?

Induction in the receiver antenna

We see above that, an oscillating magnetic field creates an oscillating electric field in a conductor. When the oscillating magnetic lines fall on the receiver antenna, just like the electromagnetic induction in a dynamo or a transformer, tiny oscillating electricity is created within the antenna and a tuned receiver circuit can pick up the transmitted signal.

Why do radio waves are bending and light is not?

Bending of magnetic lines is caused by the mutual repulsion between them. As the length of oscillating magnetic lines increase, the chances of mutual repulsion between them will be also increased (radio wave to microwave) and they bend significantly. But short wavelength photons make minimum mutual repulsions and they travel almost straightly.

"Since the photon (intermittent) nature of light, it is very difficult to influence on light by magnetic field. But a continues radio wave transmitted by a simple radio wave transmitter, can be disturbed with the help of a strong magnetic field".