The propagation property is often referred to as radiation . All electromagnetic waves are classified as radiation for this reason and, as we will soon see, the word does not connote something dangerous even though it has come to mean this in many people's minds. In fact, it is the stuff higher in frequency than visible light that has some of the most dramatic biological effects. It is also instructive to make the distinction between energy and power at this point. Energy is contained by each photon and is related to its frequency.
Power indicates the number of photons that are present at one time.
A related term, Power-Density , is the number of photons that pass through a square unit of area at one time. Everything in the universe is made up of chemical compounds, which are combinations of atoms that are held together by chemical bonds. Each atom is made of a nucleus, containing a number of protons, and an equal number of electrons orbiting it. Now, let's get back to our topic. Since DNA is a chemical compound with trillions of chemical bonds, all it takes to disrupt the structure of DNA is to knock one shared electron out of orbit.