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Uncertainty in radioactive half-life experiment

Smythe · 2012-04-05 14:51:30

I have conducted an experiment and found the gradient λ of a graph to be (2.15x10^-4) +- (0.15x10^-4) The graph being ln(A) i.e. the number of disintegrations/unit time - dN/dt against time t The half-life is T(1/2) = ln(2)/λ = -3223.9 How do I find the uncertainty in the half-life? Thank you!

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05-04-2012 3:51pm

#1

Smythe

Registered Users Posts: 434 ✭✭

Join Date: March 2010

Posts: 232

I have conducted an experiment and found the gradient λ of a graph to be (2.15x10^-4) +- (0.15x10^-4)

The graph being ln(A) i.e. the number of disintegrations/unit time - dN/dt against time t

The half-life is
T(1/2) = ln(2)/λ = -3223.9

How do I find the uncertainty in the half-life?

Thank you!

0

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#2 05-04-2012 5:10pm
Smythe

Registered Users Posts: 434 ✭✭

Join Date: March 2010

Posts: 232

I now realise that the % uncertainty in λ is 0.15/2.15 = 0.069

Therefore multiply T(1/2) of -3223.9 by 0.069 which equals ±224.9, which is the uncertainty.

3223.9 ± 224.9

How do I correct this to take account of significant figures?

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