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What is the electromagnetic spectrum? - R
What is the Electromagnetic Spectrum?
By: Cameron F.
In 1873, James Clerk Maxwell published a theory on the electromagnetic spectrum. He believed that radiation moved at the speed of light across space. Scientist use the name electromagnetic spectrum to refer to the different types of radiation as a group. Some radiation you can see, others you can feel or hear, and yet others you cannot sense at all. Each type of radiation has its own uses. For instance, some radiation is used for communication like radios, telephones and television.
Figure 1 James Clerk Maxwell
Types of Electromagnetic Radiation
Figure 2 Examples of the Electromagnetic Spectrum
waves are used for wireless transmission of sound, information, communication, and aircraft navigation.
Microwaves cook your dinner in minutes and help scientist learn about the universe.
Infrared light is beyond the end of the visible range for humans. Night vision goggles helps our military see the infrared light given off by our skin.
Visible light is the only part of the spectrum that the
Ultraviolet light is produced by the sun and can cause sun burn. UVB is the main source of
and skin cancer.
X-rays are used by doctors to see our bones for medical treatment.
Gamma waves are emitted by nuclear power plants and by our universe. Gamma rays are to treat cancer.
Radiation is made up of photons that travel at the speed of light. Photons are massless particles that contain energy. These photons travel in a wavelike pattern. Scientist measure the wavelength from crest to crest or top to top of the wave.
Figure 3 How to Measure a Wavelength
How to measure
Scientist also measure the energy contained by the radiation wave form by measuring the frequency. Frequency is measured in Hertz or cycles per second. You measure frequency by counting how many times per second a wave moves across the line of zero. Radio waves have the lowest frequency but the longest wavelength and Gamma waves have the highest frequency but the shortest wave length.
Electromagnetic spectrum and wavelength
The electromagnetic spectrum can be ordered from longest wavelength and lowest energy to shortest wavelength and highest energy starting from radio waves, microwave, infrared, visible, ultraviolet, X-Rays, and ending with Gamma rays.
Figure 5 Electromagnetic Spectrum and Wavelength
You deal with the electromagnetic spectrum every day. You use radio waves every day when you when you watch your favorite TV show, listen to the newest hit song on the radio or talk to your friends on the
You tune into a station by stetting your radio to the same frequency as the radio station is sending out its waves.
The universe is the biggest producer of gamma-rays.
The wavelength of a radio wave can be the large as the length of a football field.
The wavelength of visible light can be as small as a virus.
Each color of the rainbow has its own wavelength. Red has the longest wavelength, then orange, yellow, green, blue, indigo and violet.
Figure 6 Wavelengths of the Colors of the Rainbow
Glossary of Terms
– top of wave
– electric and magnetic charges that apply influence
- How many times a wave crosses the line of zero; the unit of measure is Hertz (cycles) per second.
- massless particles that contain energy
- photons that travel in waves at the speed of light
– a continuous group or range of objects such as waves
– valley or bottom of wave
– length of the wave measured from crest to crest
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