# Electromagnetic Waves

## What are Electromagnetic Waves?

Electromagnetic waves or EM waves are waves that originate from the vibration of the electric and the magnetic fields. That is, EM waves consist of magnetic and electronically oscillating fields.

When an electrical field comes into contact with a magnetic field, electromagnetic waves form.

Therefore, they are called electric waves. An electromagnetic wave is a perpendicular, at a right angle, in the electrical field and the magnet field. They are perpendicular to the EM wave path.

## How are Electromagnetic waves formed?

A charged particle creates an electrical field in general. A force is applied to other charged particles by this electric field. In a direction other than the field direction, positive charges accelerate, and negative charges accelerate.

A moving filled particle generates the magnetic field.

This magnetic field exercises a torque on other moveable particles. The force on these loads is still dependent on their speed direction and therefore only adjusts the speed direction, not speed.

Thus, an accelerated charged particle produces the electromagnetic camp. Electromagnetic waves are nothing more than electrical and magnetic fields flowing in open space at light crates.

When the charged particle oscillates around a place of balance, it is an accelerated charged particle. If the charged particle’s frequency of oscillation is f, an electromagnet with frequency f will be produced. This wave’s wavelength λ is given by λ  = c / f. Electromagnetic waves transmit space energy.

## Graphical Representation of Electromagnetic Waves A sinusoidal diagram displays electromagnetic waves. It consists of electric and magnetic fields that differ from time to time and are perpendicular to the wave propagation direction.

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The transverse aspect of the electromagnetic waves. The crest is the highest point of the wave, and a trough is the lowest. In a vacuum, the waves are traveling at 3 x 108m.s-1 constant speed.

## Mathematical Representation of Electromagnetic Wave

A plane Electromagnetic wave traveling in the x-direction is of the form

E(x,t)=Emaxcos(kx−ωt+Φ)

B(x,t)=Bmaxcos(kx−ωt+Φ)

In the electromagnetic wave, E is the electric field vector and B is the magnetic field vector.

Maxwell gave the basic idea of electromagnetic waves, while Hertz experimentally confirmed the existence of an electromagnetic wave.

The direction of propagation of the electromagnetic wave is given by vector cross product of the electric field and magnetic field. It is given as:

E⃗ ×B⃗.

## Electromagnetic Wave Equation

The electromagnetic wave equation describes the distribution in vacuum or by media of electromagnetic waves.

The electromagnetic wave equation is a component differential equation of the second order.

The wave equation is a 3D shape.

The homogeneous form of the equation is written as,

(υ2ph▽2−∂2∂t2)E=0(υ2ph▽2−∂2∂t2)B=0

Where υph=1μϵ√

## The intensity of an Electromagnetic Wave

I=PA=12cϵ0E20=12cμ0B20

## Speed of Electromagnetic Waves in Free Space

It is given by

C=1(μ0ϵ0)√

Where,

μ0 is called absolute permeability. Its value is 1.257×10−6TmA−1

ϵ0 is called absolute permittivity. Its value is 8.854×10−12C2N−1m−2

C is the velocity of light in vacuum = velocity of electromagnetic waves in free space = 3×108ms−1

## Electromagnetic Spectrum

Electromagnetic waves are classified according to their frequency according to their wavelength λ=cf.

Wavelength ranges of different lights are as follows,

For visible light – approx. 400 nm to approx. 700 nm

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For violet light – approx. 400 nm

For red light – approx. 700 nm

## Applications of Electromagnetic Waves The following are a few electromagnetic wave applications:

In a vacuum or using no medium, the electromagnetic wavelength may transfer electricity.

In information technologies, electromagnetic waves play a significant role.