Electromagnetic Spectrum
Just as light travels in waves, so also do other forms of energy including radio waves, microwaves and ultraviolet waves. These are all electromagnetic waves.
So what exactly is this electromagnetism? So basically, electromagnetism is the branch of physics which deals with the study of electromagnetic force which is a type of physical interaction that occurs between electrically charged particles.
So, in simple words, it is an attraction between particles created by electricity.
Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. Like other waves, electromagnetic waves transfer energy from one place to another. So, in physics, the transfer of energy by electromagnetic waves is called electromagnetic radiation. Electromagnetic radiation consists of waves of the electromagnetic field, propagating through space, carrying electromagnetic energy.
The total range of electromagnetic waves is called the electromagnetic spectrum. The colors of rainbow form the only part of this spectrum that we can see. All the other waves are invisible. The electromagnetic spectrum is made of light with many different wavelengths, and each is reflected at a different angle.
Although all these waves travel at the speed of light, each group of waves has a different wavelength and carries a different amount of energy.
Infrared, microwave and radio waves have a longer wavelength and carry less energy than visible light. Whereas, ultraviolet, X-Ray and gamma rays have a shorter wavelength and carry more energy.
Let's have a look at each one of them, one by one!
Types of Electromagnetic Radiation:
1) RADIO WAVES: The electromagnetic waves used to broadcast radio and television have wavelengths ranging from hundreds of meters down to a few tens of centimeters. The size of the aerial/ antenna needed to detect a radio signal is closely related to the wavelength. These waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum with frequencies of 300 gigahertz and below.
2) MICROWAVES: Microwaves are the shortest of the radio waves and are used to transmit radar signals. Some microwaves have the same frequency as water molecules, and can be used to cook moist food. The energy of the microwaves is converted into heat as the water molecules vibrate. Microwaves have a frequency ranging between 300 Megahertz to 300 gigahertz while the wavelength ranges from 0.1 centimeters to around 30 centimeters.
3) INFRARED WAVES: All warm objects give off infrared waves rays. Special photographs taken with infrared rays are called thermographs. Each color represents a different skin temperature, ranging from yellow which is the hottest, to blue which is the coldest. The human eye can not see infrared waves, but can feel it as heat. Their frequencies range in about 300 gigahertz to 400 terahertz.
4) ULTRAVIOLET RAYS: Sunlight contains UV-Rays. Small amounts of UV rays are good for us, but large amounts can be bad for our eyes and can even cause skin cancer. It is these waves that tan and burn fair skins. It has a wavelength of 10 nanometers with a corresponding frequency of around 30 petahertz.
5) X-RAYS: X-rays have enough energy to travel through a considerable thickness of material - including the human body. On an X-ray photograph the denser parts of the body show up as shadows. The have a frequency of around 30 exahertz.
6) GAMMA RAYS: Gamma rays are very penetrating. They carry lots of energy and damage living cells as they pass through. Gamma rays are given out by the nuclei of radioactive atoms in nuclear reactions and explosions. They have frequencies above 10 exahertz and wavelengths around 10 picometers (less than the diameter of an atom). Amazing!
So, these were some electromagnetic spectrums!
Facts time!
1) The Sun is a source of electromagnetic waves!
2) Visible light is the only part of the electromagnetic spectrum we can see!
History
JAMES CLERK MAXWELL: It was the Scottish physicist James Clerk Maxwell (1831-1879) who formulated the equations of electricity and magnetism that predicted the existence of electromagnetic waves.
Approximately 15 years after Maxwell published his equations, Heinrich Hertz first produced and detected radio waves.
SO, THAT'S IT!
I hope you enjoyed this episode and learned a lot of new things from the concept of electromagnetic spectrums and light!
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