Photosynthesis-2
Light is a form of Electromagnetic Radiation. The Sun is the most immediate source of electromagnetic radiation (EMR).
EMR has wave-like properties.
Wavelength can be measured as the distance between one wave crest and the next. It is usually measured in meters (m) or nanometers (nm). A nanometer is 10-9 m.
Electromagnetic waves have electrical and magnetic properties.
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The major types of electromagnetic radiation are displayed in the table below.
The Electromagnetic Spectrum (EMS)
| NAME | Wavelengthl RANGE (m) |
Frequency n (Hz) |
ORIGIN/ CAUSE |
INTERESTING FACTS |
USES / RELATED CAREERS |
|
>10 5 |
<10 2 |
vibrating atoms or molecules over macroscopic distances |
60 Hz hum heard near electric transformers |
transmits electric energy |
|
|
|
vibrating atoms or molecules over macroscopic distances |
low frequencies are reflected by earth's atmosphere |
Radio and TV |
Microwave |
|
|
vibrating atoms or molecules |
these waves are blocked by "dots" on ml oven doors |
cooking; long distance TV and phone; radar; terrain mapping |
|
|
|
vibrating atoms or electron transitions |
passes through haze in the atmosphere |
heating & drying; satellite remote sensing |
| Visible/PAR |
4-7x10-7 | 7.5x1014-4.3x1014 | vibrating atoms or electron transitions |
about 1/40 of total EMR spectrum |
what the eye and typical film can
"see"; optometrist |
(UV) |
|
|
vibrating atoms or electron transitions |
|
germicidal, photo-chemical, photo-electric effects; produce mutations |
|
|
|
electron transitions and braking |
l is size of atom |
Chromosome damage, produce mutations; crystallography; remote sensing |
gamma |
<10 -11 |
>10 19 |
nuclear transition |
can cause cell & tissue damage; ionization |
research into structure of nucleus; geophysics; mineral exploration |
