Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Which halflife formula is correct?

  1. Apr 11, 2005 #1
    Which half - life formula is correct? Please help

    is it
    Al = Ao(1/2)^(t/h)
    or
    Al = Ao(1/2)^(h/t)
    ?
    where Ao =original amount
    Al = amount left
     
    Last edited: Apr 11, 2005
  2. jcsd
  3. Apr 11, 2005 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Well, what do YOU think? Suppose t were equal to 2h.

    The first formula gives AI= Ao(1/2)^(2h)= Ao((1/2)^h)^2 which is less than the amount at the half life.

    The second formula gives AI= A0(1/2)^(h/2)= A0((1/2)^h)^(1/2) which is more than the amount at the half life.

    If you let this (radioactive subtance?) sit longer, will it gain or lose mass?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook