All about Electromagnetic Waves

Energy and momentum are transferred from one location to another when waves move through space or vacuum. Waves can be classified according to various factors, but the most important is the medium’s requirement.

There is no medium needed for electromagnetic waves to travel from one location to another. These waves propagate through space due to the oscillations of the electric and magnetic fields. The electromagnetic fields fluctuate in perpendicular directions. These waves are used to differentiate or categorise according to their frequency and wavelength.

What are electromagnetic waves? 

Electromagnetic waves, or EM waves, are formed when an electric field interacts with a magnetic field. On the other hand, EM waves are made up of fluctuating magnetic and electric fields.

Electromagnetic waves are generated when an electric field interacts with a magnetic field. As a result, they are referred to as ‘electromagnetic’ waves. An electromagnetic wave’s electric and magnetic fields are perpendicular to one another. Additionally, they are perpendicular to the EM wave’s direction.

In a vacuum, the speed of electromagnetic waves is 3.00 x 108 ms-1. Neither the magnetic nor electric fields can deflect them. However, they can exhibit diffraction or interference. Electromagnetic waves may travel through any medium, including air, solid matter, and vacuum. It can go from one area to another without using a medium. Mechanical waves (sound or water waves) require a medium to propagate. Electromagnetic waves are “transverse” waves. This means that their amplitude and wavelength are measured.

Electromagnetic spectrum:

A wave’s crest is its highest point, while its trough is the lowest. Electromagnetic waves have different frequencies. This is called the electromagnetic spectrum. Electromagnetic waves (EM waves) include radio waves, X-rays, microwaves, gamma rays, and infrared waves.

Sources of electromagnetic waves

• Whenever electrically charged ions oscillate (accelerating charges), electromagnetic waves are formed as a result.
• The accelerating charge causes the electric field to vibrate, resulting in the generation of an oscillating magnetic field as a result.
• EM waves are generated by the oscillating electric and magnetic fields.
• The charge’s electric field is static while it is at rest. As a result, no electromagnetic waves would be generated because the electric field does not change with time.
• When a charge moves at a constant velocity, its acceleration is zero. Since the variation in the electric field over time is also consistent, no electromagnetic waves would be generated.
• Electromagnetic waves (EM waves) can only be formed by accelerating charges, as this indicates.
• For example, think about a charged particle that is oscillating. An electric field oscillates, which makes a magnetic field that keeps moving with it.
• As the magnetic field oscillates, it generates an oscillating electric field, and so on.
• When a wave is propagated, it generates electric and magnetic fields.
• The term “electromagnetic wave” refers to a wave where all of these processes occur simultaneously.
• Also, an EM wave’s frequency is always equal to the oscillating particle’s frequency.

Properties of electromagnetic waves

• Electromagnetic waves propagate through electrical and magnetic fields perpendicular to one another.
• In a vacuum, electromagnetic waves travel at a constant speed of 3 x 108 ms-1.
• Electric and magnetic fields do not affect electromagnetic waves.
• Interference or diffraction can occur between electromagnetic waves.
• Polarisation is a property of electromagnetic waves.
• Electromagnetic waves do not require a medium of transmission. The earth receives energy from the sun via electromagnetic waves.
• An electromagnetic wave’s frequency (v) is directly related to its wavelength (λ).

c = v λ = ω/k.

• The speed of electromagnetic waves in a vacuum or free space is a universal constant.
• Electromagnetic waves do not require a material medium to exist. However, they can also spread through a medium.
• To propagate, electromagnetic waves need time-varying electromagnetic fields.
• Electromagnetic waves carry both energy and velocity.

The energy of EM wave 

When electromagnetic waves propagate through the atmosphere, they carry a lot of energy. They have a wide range of practical applications in our daily lives due to this feature.

An electric and magnetic field transmits an EM wave’s energy.

Mathematically,

The total energy contained in an electromagnetic wave per unit volume,

ET = Electric field energy storage per volume + magnetic field energy storage per volume.

⇒ET =(1/2)(E2ε0)+(1/2)(B2/μ0) 

It has been demonstrated experimentally.

The speed of an EM wave is equal to the speed of light.

⇒c = E/B

Electromagnetic spectrum

Electromagnetic waves have wavelengths ranging from a few kilometres to a fraction of the area of an atomic nucleus, and the electromagnetic spectrum encompasses the entire range of these wavelengths and photon energies. When electromagnetic waves travel in a vacuum, they travel at the same speed as light. At different wavelengths, photon energy, and frequencies, they do this.

The electromagnetic spectrum comprises a broad range of electromagnetic radiation, broken down into a plethora of smaller ranges known as portions. Infrared radiation, visible light, and ultraviolet radiation are all subcategories of electromagnetic radiation.

Electromagnetic Waves in Electromagnetic Spectrum

The entire range (electromagnetic spectrum) is given by radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, gamma rays, and cosmic rays in the increasing order of frequency and decreasing order of wavelength.

Conclusion

According to the Electromagnetic Waves definition, EM waves are a type of electromagnetic wave that oscillates electromagnetic fields. Electromagnetic waves come in various wavelengths and frequencies, but all share a common propagation velocity equal to the speed of light.Heat transfer from the sun to the earth is made possible by these electromagnetic waves. These waves can travel through space since they do not need a medium to propagate.

Numerous electromagnetic waves are used in various disciplines, including health, defence, security, and communication.