Electromagnetic Waves

Learn how electromagnetic waves work and everyday examples.

What Starts an Electromagnetic Wave?

An electromagnetic wave (EM) is created by the changing of magnetic fields making the electric fields change as well. Because the two fields are linked and change at the same time, they create electromagnetic waves.
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How Are EM Waves Different from Mechanical Waves?

EM waves have the ability to travel through a vacuum and do not need a medium to travel through. However, mechanical waves need a medium to travel through and without one, they would not be able to transfer their energy. Also, mechanical waves start because of a disturbance in matter, while EM waves start from the changing of magnetic and electric fields.
Electromagnetic Waves

Gamma Rays

Gamma rays have the shortest wavelengths with each at a length of less than 1 x 10⁻¹¹ meters. Since the wave lengths are so small, they have the highest frequency with it being greater than 3 x 10⁻¹⁹ Hertz and the most energy at more than 2 x 10 ⁻¹⁴ Joules. Some objects that use gamma rays are machines used in the medicine field to kill cancer cells or other dangerous cells. A couple things that emit gamma rays are black holes and the Universe.


X-rays have wave lengths between 1 x 10 ⁻¹¹ and 1 x 10 ⁻⁸ meters, a high frequency between 3 x 10 ⁻¹⁶ and 3 x 10 ¹⁹ Hertz, and a high energy level between 2 x 10 ⁻¹⁷ and 2 x 10⁻¹⁴ Joules. They are used on Earth for things like x-rays and airport scanners and can be generated by extremely hot gases.

Ultra-violet Radiation

Ultra-violet radiation have wavelengths between 1 x 10⁻⁸ to 4 x 10⁻⁷ meters and have a semi-high frequency between 7.5 x 10¹⁴ and 3 x 10¹⁶ Hertz. The energy levels of ultra-violet radiation are between 5 x 10⁻¹⁹ and 2 x 10⁻¹⁷ Joules. The Sun, young stars, and counterfeit money detection machines all use or emit ultra-violet radiation.
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Visible Light

Visible light has wavelengths between 4 x 10⁻⁷ and 7 x 10 ⁻⁷ meters and has a frequency between 4 x 10¹⁴ and 7.5 x 10¹⁴ Hertz. The energy level is between 3 x 10⁻¹⁹ and 5 x 10⁻¹⁹ Joules. Fireflies, light bulbs, and stars all emit visible light allowing humans to see them.

Infrared Waves

Infrared waves have wavelengths between 7 x 10⁻⁷ and 1 x 10⁻³ meters and has a frequency between 3 x 10¹¹ and 4 x 10⁻¹⁴ Hertz. Because the frequency is a little slower, the energy levels are on the slower side between 2 x 10⁻²² and 3 x 10⁻¹⁹ Joules. Night vision goggles, infrared lamps, and astronomers mapping stardust all use infrared waves to function.


Microwaves have wavelengths between 1 x 10 ⁻³ and 1 x 10 ⁻¹ meters and frequencies between 3 x 10 ⁹ and 3 x 10 ¹¹ Hertz. The energy levels of microwaves are between 2 x 10 ⁻²⁴ and 2 x 10 ⁻²² Joules. Microwaves (the kitchen appliance), astronomers, and satellites all use microwaves when preforming their tasks.

Radio Waves

Radio waves have a wavelength greater than 1 x 10⁻¹ meters and a frequency less than 3 x 10⁹ Hertz. The radio wave energy levels are less than 2 x 10⁻²⁴ Joules. Stars and gases in space, radios, and televisions all use radio waves to function.