how is radiation strength measured
EM radiation is a periodic wave motion. The number of repetitions of the waveform, or cycles per second, is called the frequency and is measured in Hertz (Hz). 1 kilohertz (kHz) = 1000 Hz, 1 megahertz (MHz) = 1 million Hz, 1 gigahertz (GHz) = 1 billion Hertz, 1 terahertz (THz) = 1 trillion Hertz, etc.