Uncertainties Flashcards
Random uncertainties are..
Due to factors that cannot be completely eliminated by the experimenter.
Approx Random uncertainty equation
^R= Rmax-Rmin/ n
Remember when displaying answer in random uncertainties that
The uncertainty must be to 1 sig fig and have the same number of decimal points as the answer.
Scale reading uncertainty for analogue
+- 1/2 smallest division
Scale reading uncertainty for digital
+- 1 smallest division
Systematic uncertainties have
Consistent effects on the quantities being measured
Systematic uncertainties are caused by
Experimental design or issues with equipment
Accuracy
How reflective the results are of the true value
Precision
How close the numbers are together
Calibration uncertainties
Manufacturers claim for the accuracy of the equipment used will be included on product.
Calibration uncertainties are…… in nature
Systematic
Why do calibration uncertainties occur
The equipment may vary depending on temperature for example.
Ie metal ruler will expand when hot and contract when cold as such it will change the experimental accuracy
When do we not have to combine uncertainties
If one of the uncertainties is less than a 1/3 of the largest uncertainty then we ignore it.
How to combine uncertainties for S=PQ
Or S=P/Q
%DS= ((%DP)^2+(%DQ)^2))^1/2
[D = delta triangle]
How to combine uncertainties for S=P+Q
or S=P-Q
DS=(DP^2+DQ^2)^1/2
