Part 1 of Essay
In the modern society, radio is the most widely used medium of broadcasting and electronic communication : it plays a major role in many areas such as public safety, industrial manufacturing, processing, agriculture, transportation, entertainment, national defense, space travel, overseas communication, news reporting and w ....

Part 2 of Essay
.... of one wave to the crest of the next. Radio frequencies are measured in units called kilohertz, megahertz, and gigahertz. (1 kilohertz = 1000 hertz : 1 megahertz = 106 hertz, 1 gigahertz = 109 hertz). All radio waves fall within a frequency range of 3 kilohertz, or 3000 cycles per second to 30 gigahertz. Within the range of frequencies, radio waves are further divided into two groups or bands such as very low frequency ( VLF 10-30 kHz ), low frequency (LF 30-300 KHz), medium frequency ( MF 300-3000 KHz), high ....