Definition of backpack. 1a : a load carried on the backb : a camping pack (as of canvas or nylon) supported by a usually aluminum frame and carried on the backc : knapsack.
Three types of radioation-Alpha, Beta, Gamma. There are three primary types of radiation: 1  Alpha-these are fast moving helium atoms. 2  They have high energy, typically in the MeV range, but due to their large mass, they are stopped by just a few inches of air, or a piece of paper.3  Beta-these are fast moving electrons. Alpha-these are fast moving helium atoms. 2  They have high energy, typically in the MeV range, but due to their large mass, they are stopped by just a few inches of air, or a piece of paper. 3  Beta-these are fast moving electrons. 4  They typically have energies in the range of a few hundred keV to several MeV.
All radiation is a form of energy, most of which is invisible to the human eye. UV radiation is only one form of radiation and it is measured on a scientific scale called the electromagnetic (EM) spectrum. UV radiation is only one type of EM energy you may be familiar with.