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Nuclear Decay question without knowing N0 or N ?

by Bowenwww
Tags: decay, knowing, nuclear
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May9-12, 03:18 PM
P: 25
1. The problem statement, all variables and given/known data
Ok so what I have an Am sample which emits alpha particles at a rate of 70Bq in 1997 and asks for the activity 8 years later (the half life of Am being 432.2 years) I found this to be 69.108 Bq, first of all does this sound right?

Secondly it asks for the number of nuclei both in 1997 AND 8 years later in 2005 - I have no idea to do this, is there an equation that relates the initial and final nuclei number without knowing either?

2. Relevant equations

3. The attempt at a solution
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May9-12, 03:25 PM
P: 3,014
A(t) = A_0 \, \exp(-\lambda \, t)

A is activity and is measured in bequerel ([itex]1 \, \mathrm{Bq} = 1 \, \mathrm{s}^{-1}[/itex])
May9-12, 03:50 PM
P: 925
Also, A(t) = λN(t)

May9-12, 04:00 PM
P: 25
Nuclear Decay question without knowing N0 or N ?

Yeah I sort of understand that it's just I don't know how to apply my answer for activity to find the nuclei number before and after
May9-12, 06:11 PM
P: 3,014
see post #3.

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