Which of the following statements best describes 'Background Radiation'?
Background radiation refers to those coming from the environment of natural radioactivity at the eahs surface and the those from direct cosmic radiation that arrives at the eahs surface. Ref: Radiation Biophysics By Edward L. Alpen, Page 432; The Biological Basis of Nursing : Cancer By William T. Blows, Page 54, 56
Radiation in the background of nuclear reactors
Radiation in the background during radiological investigations
Radiation present constantly from natural sources
Radiation from nuclear fall out