Share
Blog
Print
Email
BookmarkMicrowaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) wavelengths, but relatively short for radio waves.
See also:
Microwaves have wavelengths approximately in the range of 30 cm (frequency = 1 GHz) to 1 mm (300 GHz).
However, the boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.
A microwave oven works by passing microwave radiation, usually at a frequency of 2450 MHz (a wavelength of 12.24 cm), through the food.
Water, fat, and sugar molecules in the food absorb energy from the microwave beam in a process called dielectric heating.
Many molecules (such as those of water) are electric dipoles, meaning that they have a positive charge at one end and a negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field induced by the microwave beam.
This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion.
Microwave heating is most efficient on liquid water, and much less so on fats and sugars (which have less molecular dipole moment), and frozen water (where the molecules are not free to rotate)..
For more information about the topic Microwave, read the full article at Wikipedia.org, or see the following related articles:
Electromagnetic spectrum — The electromagnetic spectrum is the range of all possible electromagnetic radiation. Above infrared in frequency comes visible light. This is the ... > read more
Radiant energy — Radiant energy is the energy of electromagnetic waves. The term is most commonly used in the fields of radiometry, solar energy, heating and ... > read more
Electromagnetic radiation — Electromagnetic radiation is a propagating wave in space with electric and magnetic components. These components oscillate at right angles to each ... > read more
