Electromagnetic radiation Electromagnetic radiation In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space, carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays. Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light, which, in a vacuum, is commonly denoted "c". In homogeneous, isotropic media, the oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming
Petkau effect original 1972 experiment apparently revealed the potential effects of ionizing radiation on cells without natural radioprotective mechanisms in place. Petkau effect The Petkau effect is an early counterexample to linear-effect assumptions usually made about radiation exposure. It was found by Dr. Abram Petkau at the Atomic Energy of Canada Whiteshell Nuclear Research Establishment, Manitoba and published in Health Physics March 1972. The Petkau effect was coined by Swiss nuclear hazards commentator Ralph Graeub in 1985 in this book "Der Petkau-Effekt und unsere strahlende Zukunft" (The Petkau effect and our Radiating Future). Petkau had been measuring, in the usual way, the