What is electromagnetic radiation in microwaves?

Answer 1

Microwave radiation is electromagnetic radiation (waves) in the microwave portion of the electromagnetic spectrum. (An electromagnetic wave is a moving electrostatic and magnetic field. The fields are at right angles to each other, and they move through space in just this way - as moving fields. Another question is required for further explanation.) These little guys, these microwaves, are the same thing as radio waves, but of much higher frequencies. (Visible light is electromagnetic radiation, too, but of an even higher frequency than microwaves.) When one looks at electromagnetic (em) radiation (r) (em + r = emr), what is probably the most basic way to view it is by its frequency. The frequency range of microwaves is something over a few gigahertz (1 billion cycles per second or 1,000,000,000 cps) to about 300 gigahertz. Cellular phones operate on the lower end of the microwave band, and the links between the cell phone antenna towers (the cell hubs) operate on microwave frequencies also, but a bit higher up than the cell phones. Satellite communication is done at microwave frequencies. Radar and microwave ovens (2.450 gigahertz) work at microwave frequencies. Oh, and lest we forget, the term microwave can be translated into "really little wave" and that refers to its wavelength. Picture a wave traveling across a calm pond. There is a certain distance between the tops of two consecutive peaks or the bottom of two consecutive troughs, and that's the wavelength of the wave. Microwaves, those little radio waves, have wavelengths ranging from about a tenth of a meter (about 10 centimeters or about 4 inches) to about a millimeter. Those might not seem like "little" waves, but the wavelength of the waves used to broadcast the FM radio signals you might sometimes listen to is in the ball park of three meters or about 10 feet. AM radio waves (does anyone still listen?) are something like 300 meters long. So microwaves are tiny waves. That's why the eggheads (really nice guys who wear bad ties) named the emr in the roughly 3 gigahertz to 300 gigahertz range "microwaves." Some other characteristics of microwaves are that they don't like to bend around stuff. They are basically used "line of sight" which translates into the receiver being in a direct line with the transmitter and not hiding behind a hill or other terrain or structure. Yes, microwaves bounce around so your cell phone can get good coverage amongst a group of tall buildings, but microwave energy likes to "duct" and "tunnel" when it is possible and that means you don't necessarily drop a call because you can't see the tower that's linked to your phone. The antenna for use at these frequencies is much shorter compared to an antenna used at lower frequencies. (Again, think of your cell phone.) And we frequently see a microwave "dish" out there. The dish is a reflector, and it works just like you'd think. The incoming emr (notice how you're used to the lingo already?) hits the reflector and bounces off, but the reflector has a parabolic shape and it will direct the reflected energy to a central point, or focus of the reflector, and that's where the antenna will be. That concentrates the energy gathered over the area of the dish for greater gain. This is done with telescopes to collect more light for a better image of a faraway object. Make sense? Sure it does. It works with light and it works with microwaves. They're both electromagnetic waves. So now you're up to speed with microwaves. They're just little electromagnetic waves in the (about) 3 gigahertz to 300 gigahertz range (band) of frequencies. Note: there are some who would say that microwaves are in the 30 to 300 gigahertz band and exclude the 3 to 30 gigahertz band, and they may be right. But others allow for the use of the term microwave to reach down below that so-arbitrary mark of 30 gigahertz. Let's not blow a gasket and try to split hairs on this. The term microwave was in use before the em spectrum was broken up into those blocks that are shown in the nice drawing of the em spectrum at the Wikipedia article. Links are, of course, provided for the curious person who wishes to cross check the Mechanic's explanation and do some further reading.

Answer 2

One definition for the slippery term "mcrowave" is:

Radio at frequencies above 3 GHz (wavelength less than 10 cm.)

Unfortunately, the first example that everybody asks about comes with an
embarrassing confession.

The most popular question is: What's the frequency (wavelength) of the energy
in my microwave oven ?

The answer is: 2.450 GHz (12.24 cm).

If you've been following astutely, you've noticed that technically, according to
the definition up above, the radiation heating the meatloaf in your microwave
isn't 'microwave' at all. Close, but technically not.

Answer 3

The question is somewhat unclear. I'm going to assume that it's asking

"What is the radiation that cooks the food in a microwave oven ?"

The microwave oven uses a cavity magnetron to generate high power

radio waves at the frequency of 2.45 GHz.

For comparison ...

-- Various models of microwave ovens guide anywhere between 600 to 2,000 watts

of radio-wave power into the chamber where you put the meatloaf.

-- Microwave radio transmitters on 'cell' towers pump out anywhere between 1/16 watt to 1 watt

of radio wave power into the 'dish' antenna, to communicate as far as 20 or 30 miles.

Answer 4

-- A 'microwave' is a radio wave at any frequency above 3 GHz.

-- A 'microwave oven' cooks with radio waves from a high power source at 2.450 GHz.

Answer 5

A short-wavelength radio wave. An electromagnetic wave that is somewhere in between regular radio waves and infrared radiation.

Answer 6

Electromagnetic microwaves.