Uncertainty in radioactive half-life experiment

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SUMMARY

The discussion focuses on calculating the uncertainty in the half-life of a radioactive substance based on the gradient λ obtained from a graph of ln(A) versus time t. The calculated gradient is (2.15x10^-4) ± (0.15x10^-4), leading to a half-life of T(1/2) = -3223.9. The participant correctly determines the percentage uncertainty in λ as 0.069 and applies it to find the uncertainty in half-life as ±224.9, resulting in a final value of 3223.9 ± 224.9. The participant seeks guidance on adjusting this result for significant figures.

PREREQUISITES
  • Understanding of radioactive decay and half-life calculations
  • Familiarity with logarithmic functions and their applications in physics
  • Knowledge of uncertainty propagation in experimental measurements
  • Proficiency in significant figures and their importance in scientific reporting
NEXT STEPS
  • Study uncertainty propagation techniques in experimental physics
  • Learn about significant figures and their application in scientific calculations
  • Explore the relationship between decay constants and half-life in radioactive materials
  • Review examples of calculating uncertainties in various physical experiments
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Students conducting experiments in physics, particularly those studying radioactive decay, as well as educators teaching concepts of uncertainty and significant figures in scientific measurements.

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Homework Statement




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!


Homework Equations





The Attempt at a Solution

 
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I now realize 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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