If there are half as many radioactive isotopes left then the material is also half as radioactive, as radioactivity is measured in decays per second (Becquerel

If there are half as many radioactive isotopes left then the material is also half as radioactive, as radioactivity is measured in decays per second (Becquerel [1]). [1] https://en.m.wikipedia.org/wiki/Becquerel https://en.m.wikipedia.org/wiki/Becquerel