>Would this factoid be true pre-1945 Oppenheimer / Los Almost test? Yes - K-40 is primordial and Ra-226 is part of the uranium series from U-238, which is also

>Would this factoid be true pre-1945 Oppenheimer / Los Almost test? Yes - K-40 is primordial and Ra-226 is part of the uranium series from U-238, which is also primordial.