Question 136965
Radium has a half-life of 1660 years. If the initial amount of radium is 200 grams, how much will remain in 500 years? 
:
Just use the half-life equation which is:
:
{{{A = Ao*2^(-t/h)}}}
Where:
A = remaining amt
Ao = initial amt
t = time
h = half-life of the given substance
:
Substituting the given values we have:
:
{{{A = 200 * 2^(-500/1660)}}}
:
A = 200 * .81157; find that 2^(-500/1660) = .81157 on a good calc
:
A = 162.3 gr left after 500 yrs