what does longwave radiation mean?

Answer 1

The term 'longwave' came into use originally to contrast it with 'shortwave' - both describing different types of radio sets in use in the time. Shortwave radio was more powerful and coud be reflected by the ionosphere, making communication possible to people around the world. This also made it unsuitable for use by radio stations, which used longwave bands of the electromagnetic spectrum instead. Another term for longwave is 'LF', for low-frequency.

Answer 2

...and finally, there is a long wave radiation that sits even lower than LW radio waves:
Extremely low frequency (ELF) fields, which includes alternating current (AC) fields and other electromagnetic, non-ionizing radiation from 1 Hz to 300 Hz. ELF fields at 50 or 60 Hz are produced by power lines, electrical wiring, and electrical equipment. Some epidemiological studies have suggested increased cancer risk associated with magnetic field exposures near electric power lines.

Answer 3

Long wave radiation is low frequency.
Radio waves are much longer than those used in cell phones and vastly longer than light waves.
Infra red are the longest light waves (of the visible or near visible spectrum) but much shorter than any radio waves we use.
Light around 3,000 to 5,000 Angstrom (an Angstrom is 1/10,000th of a micron)
Radio and TV waves are in the meter range (about 1 Billion times longer than light)

Answer 4

Hi. Very low frequency. Below radio waves in the spectrum. Usually used for heat (infrared).

Answer 5

Heat, usually (in environmental studies) it is referring to thermal radiation from "room temperature" objects as in "heat is lost into space at night as long-wave radiation."