Chemistry Reference
In-Depth Information
TABLE 6
Spectrum of Electromagnetic Radiation
Radiation
Typical sources
Wavelength (cm)
Frequency (Hz)
a
Energy (eV)
b
Gamma rays
Radioactive nuclei
below 10
−9
above 3
× 10
16
above 10
5
X-rays
Atoms
10
−7
-
10
−9
3
× 10
17
- 3
× 10
19
10
3
- 10
5
Ultraviolet
Atoms
4 × 10
−5
-
10
−7
7.5
× 10
14
- 3
× 10
17
3
- 10
3
Visible
Hot bodies
7 × 10
−5
- 4 × 10
−5
4.3
× 10
14
- 7.5 × 10
14
2
- 3
Infrared
Hot molecules
10
−2
- 7 × 10
−5
3
× 10
12
- 4.3 × 10
14
0.01 - 2
Microwaves
Electronic devices
10 -
10
−2
3
× 10
9
- 3
× 10
12
10
- 0.01
Radio
Communication
above 10
below 3
× 10
9
below 0.001
a
Hz
=
Hertz, unit of frequency - the number of times a wave oscillates per unit time - measured in cycles per second.
b
eV
=
electron volt, unit of energy equal to the work done by an electron accelerated through a potenitial difference of 1 volt.
