Q: A 50-g chunk of charcoal is found in the buried remains of an ancient city destroyed by invaders. The carbon-14 activity of the sample is 200 decays/min. Roughly when was the city destroyed?(adsbygoogle = window.adsbygoogle || []).push({});

A: I used R = Ro*e^(-lambda*t) and t1/2 = ln2/lambda

t1/2 = 3.834*10^-12 s-1

and 200 decays/min = 3.33 decays/sec or 3.33 Bq

What is the initial acitivity/kg (Ro)?

The final acitivty/kg = 3.33 Bq/0.05 Kg = 66.66 Bq/Kg

Therefore R/Ro = 66.66/255

I then found the time to be 11 088 years

Can someone please check over this and see if this looks correct and advise of any corrections?

Many thanks!

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# Homework Help: Radioactive Decay

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