The electromagnetic radiation spectrum includes X rays, ultraviolet radiation, visible light, infrared radiation, heat, microwaves and radio waves. Most of the wavelength's in the electromagnetic radiation spectrum are so small that they cannot be conveniently measured by familiar units such as inches or centimeters. Scientists use the micron to describe electromagnetic radiation. X rays and gamma rays are among the shortest wave lengths in the electromagnetic spectrum. Heat rays are on the longer end of the electromagnetic spectrum.
Radio waves can be several feet to several miles long.
A feedback mechanism is a process in which the factors that produce a result are modified by the result. In a positive feedback process the factors are strengthened by the result. Positive feedback mechanisms are destabilizing to a system and thus are generally undesirable. In a negative feedback process the factors are weakened by the result. Negative feedback mechanisms are stabilizing to a system and thus are generally desirable.