Practice question · Multiple choice
You add two measured lengths: cm and cm. Assuming independent errors, the uncertainty of is…
Hints
- Independent errors sometimes push in opposite directions and partially cancel, plain addition ignores that.
- Independent uncertainties add like perpendicular vectors: a 3-4-5 triangle is hiding in the numbers.
Show the answer
A. 0.5 cm, combining in quadrature
Why
cm. Quadrature is the mathematics of partial cancellation: uncorrelated wobbles add as areas, not lengths. Straight addition (0.7) is the pessimistic bound for perfectly correlated errors.
Practise Propagation of Errors
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