Question
In: Physics
Rubidium-strontium dating. The rubidium isotope 8737Rb, a β emitter with a half-life of 4.75×1010yr, is used...
Rubidium-strontium dating. The rubidium isotope 8737Rb, a β emitter with a half-life of 4.75×1010yr, is used to determine the age of rocks and fossils. Rocks containing fossils of ancient animals contain a ratio of 8738Sr to 8737Rb of 0.0310.
Assuming that there was no 8738Sr3887Sr present when the rocks were formed, estimate the age of these fossils.
Solutions
Expert Solution
Radioactive decay of 
into 
is given below
+ 
Half life
is 4.75 
1010 years
Ratio of
to
found in the fossils of ancient animal = 0.031
Hence fraction of undecayed
atoms = 0.969
Hence from radioactive decay equation, we get
where T is half-life period of
ln(0.969) = [ -ln2
t ] / ( 4.75
1010 )
Hence age of rocks and fossil, t = - [ ln(0.969) / ln(2) ]
( 4.75
1010 ) year
t = 2.158
1010 year
genius_generous answered 2 years agoRelated Solutions
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