Panasonic Microwave Ovens with Inverters Technical Manual page 35

Non-ionizing Radiation
We take advantage of the properties of non-ionizing radiation for common tasks:
• microwave radiation: telecommunications and heating food
• infrared radiation: infrared lamps to keep food warm in restaurants
• radio waves: broadcasting
Non-ionizing radiation ranges from extremely low frequency radiation, shown on
the far left through the audible, microwave, and visible portions of the spectrum
into the ultraviolet range.
Extremely low-frequency radiation has very long wavelengths (on the order of a
million meters or more) and frequencies in the range of 100 Hertz or cycles per
second or less. Radio frequencies have wavelengths of between 1 and 100
meters and frequencies in the range of 1 million to 100 million Hertz.
Microwaves that we use to heat food have wavelengths that are about 1
hundredth of a meter long and have frequencies of about 2.5 billion Hertz.
Ionizing Radiation
Higher frequency ultraviolet radiation begins to have enough energy to break
chemical bonds. X-ray and gamma ray radiation, which are at the upper end of
magnetic radiation, have very high frequency --in the range of 100 billion billionth
Hertz--and very short wavelengths--1 million millionth of a meter. Radiation in this
range has extremely high energy. It has enough energy to strip off electrons or,
in the case of very high-energy radiation, break up the nucleus of atoms.
Ionization is the process in which a charged portion of a molecule (usually an
electron) is given enough energy to break away from the atom. This process
results in the formation of two charged particles or ions: the molecule with a net
positive charge, and the free electron with a negative charge.
Each ionization releases approximately 33 electron volts (eV) of energy. Material
surrounding the atom absorbs the energy. Compared to other types of radiation
that may be absorbed, ionizing radiation deposits a large amount of energy into a
small area. In fact, the 33 eV from one ionization is more than enough energy to
disrupt the chemical bond between two carbon atoms. All ionizing radiation is
capable, directly or indirectly, of removing electrons from most molecules.
There are three main kinds of ionizing radiation:
• alpha particles, which include two protons and two neutrons;
• beta particles, which are essentially electrons; and
• gamma rays and x-rays, which are pure energy (photons).
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