Define background radiations and identify its sources
Background radiations are the radioactive radiations to which we are exposed even in the absence of an actual radioactive source. There are two sources of background radiations: 1. Internal source: The radioactive substances such as potassium (K-40), carbon (C-14) and radium present inside our body. 2. External source: Cosmic rays, naturally occurring radioactive elements such as radon-222 and solar radiations.