The range of all the electromagnetic radiations is known as the electromagnetic spectrum. The electromagnetic spectrum includes radiations having frequencies from 1Hertz to 1025 Hertz. In the vacuum, electromagnetic radiations travel at the speed of light, which is 3 x 108 m/s. Though they travel at a constant speed they have a range of wavelength, frequency and photon energies. The electromagnetic radiations in the spectrum further contain many subranges which are commonly referred to as portions.
The entire range of the electromagnetic spectrum and electromagnetic waves consists of following radiations- radio waves, microwaves, infrared radiation, visible light, ultraviolet light, X-rays, gamma rays and cosmic rays.
Applications of Electromagnetic Radiations
- Radio waves: The radio waves have frequencies less than 3 x 1011 Hertz. Radio waves have the highest wavelength in the electromagnetic spectrum. Radio waves are mainly used in the radio communication system.
- Microwaves: Microwaves have a frequency between radio waves and Infrared radiation. The frequency of microwaves ranges from 3 x 1011 Hertz to 1013 Hertz. Microwaves are used in the oven, which is used for cooking purposes. Microwaves are also used by astronomers to study the structure of stars and galaxies.
- Infrared Rays: The frequency of infrared rays ranges from 1013 Hertz to 1014 Hertz. The infrared radiations are used as a heating source. Infrared heaters are used in plastic welding, curing of coating etc in place of contact heating and convection oven
- X-rays: X-rays have a frequency range from 1017 Hertz to 1020 Hertz. X-rays are used by doctors to take the image of the bones and teeth. Bones and teeth block the x-rays and show up as white on the black background. X-rays are also used in airports for the security check of the bags
- Gamma Rays: They have a frequency range from 1020 Hertz to 1024 Hertz. Gamma rays are used in radiotherapy. They are also used in the nuclear industry.
- Ultraviolet Rays: They have a frequency range from 1015 Hertz to 1017 Hertz. The sun is the main source of UV rays. The UV rays help our body produce vitamin D. They are used in industrial processes and in medical purposes for killing bacteria, creating fluorescent effects, phototherapy etc.
- Visible Right: Visible light falls in the range of 4 x 1014 – 8 x 1014 Hertz. We use visible light to see the different colours. The human eye can detect only the visible light from the electromagnetic spectrum.
The electromagnetic waves consist of electric and magnetic waves oscillating perpendicular to each other. The direction of propagation of the electromagnetic waves is perpendicular to the electric field and magnetic field.
Properties of Electromagnetic waves
The properties of electromagnetic waves include its non-mechanical property, the speed with which the waves travel etc. The electromagnetic waves are non-mechanical waves that do not require a material medium to travel. They are transverse in nature. They travel with the constant speed in the vacuum. Electromagnetic waves travel with the speed of light which is 3 x 108 m/s. The oscillating electric field and magnetic fields are in the same phase.