What is electromagnetic radiation?

The World Health Organisation (WHO)
defines electromagnetic fields on its Webpages dedicated to the concerns
regarding the increasing presence of this form of radiation. In essence, an
electromagnetic field is comprised of two components, one being an electric
field generated by differences in voltage and another being a magnetic field
generated by the flow of current. The field propagates at the speed of light
(300,000 kilometres per second or 186,000 miles per second) in waves of a
certain length that oscillate at a certain frequency (number of oscillations or
cycles per second). In the electromagnetic range, gamma rays given off by
radioactive materials, cosmic rays, and X-rays are all dangerous to humans and
other organisms because of the relatively high energy "quanta" (packets) they
carry (high frequency or short-wavelength waves). Such rays lead to "dangerous
radiation" (ionizing; i.e., with an ability to break bonds between molecules).
Mobile phone systems also act in the electromagnetic range (sometimes
referred to as "microwave" or "radiofrequency"), however, the frequency
(energy "quanta") of the longer-wavelength waves associated with this
technology is lower (and therefore safer to humans) and regarded as "nonionizing"