Verified Answer :

I'm not sure what your question is. But, the half life is the amount of time required for half the material to decay. For U238 this is 4.5 billion years, whilst for Fr-223 (Francium) its about 22 minutes. To calculate the time for something to decay you need to use the equation:
MassĀ (after time t) = Mass (initial) * (0.5)^(time/half life)
Hope this helps

False.

The time required for radioactive elements, whereby they decay to
half their original mass is called the "Half life" of the element


Not the average life.