Course 2 Part 1

Question 1

Propagation of experimental uncertainties

Answer 1

• Often need to calculate other quantities from measured value(s). How do the experimental uncertainties feed through?
• For example, if we have measured λ = 101.5 ± 0.2 m. What is the uncertainty in the frequency, ?
• KEY PRINCIPLE: if the uncertainty on a value is small in comparison to others, it will have negligible effect on the overall result. (Same principle as significant figures in calculations.)
• So though most fundamental constants e.g. NA, h, c, have uncertainties*, they can be treated as constants for most calculations (but use enough sig. figs!)