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## Homework Statement

Carbon-14 decays by β emission and has a half-life of 5570 years.

- What is the decay constant of carbon-14?
- What is the activity of 1 g of carbon if 1 in 10
^{12}atoms are carbon-14? - After what time will the activity per gram have fallen to 3 Bq?

## Homework Equations

λt

_{½}= ln(2)

A = A

_{0}e

^{-λt}

A = λN

## The Attempt at a Solution

__Question 1__[/B]

λt

_{½}= ln(2)

λ= ln(2)/5570

= 1.24 * 10

^{-4}year

^{-1}

__Question 2__Mr of carbon-14 is 14 g mol

^{-1}

1 mol = 6.022*10

^{23}atoms

Atoms in 1 g = (6.022*10

^{23})/14

= 4.30*10

^{22}atoms

Don't know what to do from here. Any help would be appreciated.

Thanks