Each case of communicable disease is the result of an orderly progression in. a series of events. This series of events may be described as a three-link chain, each. link representing a factor essential to the transmission of disease. These links (figure 1-1) are: (1) The source of the disease (reservoir) (2) The means by which the disease may be transmitted (mode of.
Radio Waves. Radio waves are a type of electromagnetic (EM) radiation with wavelengths in the electromagnetic spectrum longer than infrared light . They have have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves, radio waves travel at the speed of light. Naturally occurring radio waves are made by lightning or by astronomical objects.
em waves are transverse in nature. the electric and magnetic field vectors are perpendicular to the direction of propagation of waves. Electromagnetic waves in pure vacuum ar â¦ e transverse, but in a plasma (ionized gas) electromagnetic waves can occur as transverse or longitudinal.9 people found this useful.ransverse waves are â¦ like ocean waves. They move the medium perpendicular to the medium which is the substance the wave is traveling on. Longitudinal waves are like a slinky. They compress and rarefact (The coils get close and move away).