current vs radioactivity

current

noun
  • the amount of electric charge flowing in each unit of time. 

  • a tendency or a course of events 

  • The generally unidirectional movement of a gas or fluid. 

  • The part of a fluid that moves continuously in a certain direction, especially (oceanography) short for ocean current. 

adj
  • Electric; of or relating to electricity. 

  • Generally accepted, used, practiced, or prevalent at the moment. 

  • Existing or occurring at the moment. 

radioactivity

noun
  • The radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc. 

  • Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus. 

How often have the words current and radioactivity occurred in a corpus of books? (source: Google Ngram Viewer )