W AV E L E N GT HS
600 – 0.187m
RADIO WAVES
FR E Q U E N C IE S
W AVEL EN GTHS
500 kHz – 1600 MHz 600 – 0.187m Q U A NT U M E NE R G I ES
2 x 10 -9 – 0.66 x 10 -5 eV Radio waves are the longest waves in the electromagnetic spectrum. They are used for radio broadcasts, amateur radio, television, and mobile phones. The wavelengths can range from as large as over a mile long, to about a 10th of a meter. Different parts of the radio spectrum have been allocated to various services. The largest of which is AM Radio. Here the frequencies range from about 500-1500 kHZ and the wavelengths range from about 200-600 m (although certain wavelengths can be larger, as mentioned above). The next largest range of the Radio wave spectrum is the 'Short Wave'. They are part of the general range referred to as "radio frequencies" or RF. And their frequencies range from 1605 kHz to 54 MHz, and their wavelengths range from 187 - 5.55 m.Finally, the last range within the radio wave spectrum is the smallest of the waves, which are the TV and FM radio bands. These have a frequency range of 54-1600 MHz and a wavelength range of 5.55 - 0.187 m. This range is what we most commonly associate with 'radio' waves.
W AV E L E N GT HS
187–10mm
MICRO WAVES F R E Q U E N C IE S
1.6 – 30 GHz
W AVEL EN GTHS
187 – 10mm
Q U A N T U M E N E R GIES
0.66 x 10 -5 – 0.12 x 10 -3 eV Microwaves are small enough that they can be measured in centimeters. The larger of the microwaves (nearing a foot in wavelength) can be absorbed by water, which is why they are used in microwave ovens. The water molecules absorb the energy from the microwaves and vibrate faster converting the energy into heat. Microwaves can also penetrate haze, light rain, snow, clouds, and smoke which makes them good from transmitting information from one place to another. The shorter wavelength microwaves are used in micro sensing. These wavelengths are only a few inches long. An example of this would be for the use of a radar like the doppler radar used in weather forecasts. While there are some microwave frequencies from 1,300 to 1,600 MHz, most microwave applications fall in the range 3,000 to 30,000 MHz (3-30 GHz). And their wavelengths range from 187 - 10mm.
W AV E L E N GT HS
1mm–750nm
INFRARED WAVES F R E Q U E N C IE S
14
W AVEL EN GTHS
.003 – 4 x10 Hz 1mm – 750nm Q U A N T U M E N E R GIES
0.0012 – 1.65 eV Infrared waves occur in-between visible waves and microwaves. The term infrared means 'below red' and originally the waves were called 'heat rays' because even though we couldn't see them, we could still feel the heat of them on our skin. The frequency of the infrared light is the same as that of the natural resonant frequency of individual atoms. Therefore atoms absorb the light and oscillate, causing more motion with in turn creates a higher temperature. Infrared waves have a broad range of wavelengths. The closest in wavelength to light are called 'near infrared', and the closest in wavelength to microwaves are called 'far infrared'. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic. The 'far infrared' waves are the thermal ones (as described above). The 'near infrared' with the shorter wavelengths are not hot at all. These shorter wavelengths are the ones used by your TV's remote control. The infrared waves have a frequency range of .003 - 4x1014 Hz, and a wavelength range from about 1 millimeter down to 750 nm.
W AV E L E N GT HS
750nm–400nm
VISIBLE LIGHT WAVES F R E Q U E N C IE S
14
4 – 7.5 x10 Hz
W AVEL EN GTHS
750 – 400nm
Q U A NT U M E NE R GIES
1.65 – 3.1 eV Visible light waves are the only electromagnetic waves we can see. Each one of the waves within this spectrum has a different wavelength and we see these waves as the colors of the rainbow. Red has the longest wavelength and violet has the shortest wavelength. If all of the waves are combined and seen together they make white light. If white light is shone through a prism, then the light is broken apart into the different colors of the visible light spectrum. The same effect can happen with water vapor in the atmosphere where the white light is split up into it's various wavelengths creating a rainbow. The sun is a natural source of visible light waves and our eyes see the reflection of this sunlight off of objects around us. When we see a color is it because that is the color being reflected, and all of the other colors are being absorbed. Visible light's waves have a range of frequencies from 4 - 7.5x1014 Hz and have a range of wavelengths of around 750 - 400nm.
W AV E L E N GT HS
400nm–10nm
ULTRA
VIOLET
F R E Q U E N C IE S
14
16
W AVEL EN GTHS
7.5 x10 – 3 x10 Hz 400 – 10nm Q U A N T U M E N E R GIES
3.1 – 124 eV The region just below the visible waves in wavelength is called ultraviolet. Originally they were called 'chemical rays' because they were seen to make chemical reactions happen. The photons within Ultra Violet waves have more energy than infrared or visible light and they can be damaging to our skin and eyes. Certain surfaces reflect UV rays (such as snow) and this can cause damage to our eyes. It can also cause skin cancer and wrinkles, and makes materials brittle. However it does also have some positive effects. UV light can also kill bacteria, and so it has been used in some third world countries to sanitize water. Ultra Violet waves are mostly absorbed great deal by solid substances, and even air to a certain extent. The sun is a strong source of ultraviolet radiation, but atmospheric absorption eliminates most of the shorter wavelengths. Their frequencies range from 7.5 x1014 - 3x1016 Hz, and their wavelengths range from 400-10nm.
W AV E L E N GT HS
10nm downward
X
RAYS 16 3 x10 – upward 10nm – downward F R E Q U E N C IE S
W AVEL EN GTHS
Q U A NT U M E NE R GIES
124 eV – upward X-rays have a shorter wavelength an UV rays but more energy. As the wavelengths of light decrease, they increase in energy. X-Rays have so much energy and such a short wavelength that they can go right through us. However they can not go through bone as easily as they can go through muscle, and this is because of the Calcium within our bones. This is how X-ray machines work when we go and see doctors. X-rays are usually talked about in terms of their energy rather than wavelength. This is partially because X-rays have very small wavelengths. It is also because X-ray light tends to act more like a particle than a wave. Many things in space emit X-rays, among them are black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun, and even some comets. The Earth glows in many kinds of light, including the energetic X-ray band. Actually, the Earth itself does not glow - only aurora produced high in the Earth's atmosphere. These aurora are caused by charged particles from the Sun. The frequencies of X-rays range from 3x1016 Hz upward, and their wavelengths range from around 10nm downward.
W AV E L E N GT HS
typically < 10 -12 m
GAMMA
R A Y S
F R E Q U E N C IE S
20
W AVEL EN GTHS
-12
typically >10 Hz typically < 10 m Q U A NT U M E NERGIES
typically > 1 MeV Gamma rays are the electromagnetic radiation from the nucleus as a part of a radioactive process. The resulting energy of this nuclear radiation is extremely high. They have the smallest of all of the wavelengths within the electromagnetic spectrum. And they also have the most energy. Gamma rays are often used in the medical world because they can kill living cells (cancer treatment for example). Gamma-rays are the most energetic form of light. Events such as supernova explosions or the destruction of atoms, or even the decay of radioactive material in space will produce these types of rays. These gamma rays travel great distances across the universe and when they reach earth they are stopped by our atmosphere. Different wavelengths of light penetrate the Earth's atmosphere to different depths, and our only view of the gamma rays above our atmosphere comes from high-altitude balloons and satellites in the sky. Gamma rays have a frequency range of typically below 1020 Hz, and wavelength range of typically below 10-12m.