Question

If in August 1911 Mme. Curie prepared an international standard containing
20.00 mg of RaCl2, what will the radium content of this standard be in August 2010?

Answer 1

Halflife of radium 222 is 1601 years.

content=20mg*e^(-ln2*t/1601) and t= 99 years

content= 20.00 e^(-4.286E-2)=1.168 check that.

Answer 2

Thanks!