Question
(a) How many significant figures are in the numbers 99 and 100? (b) If the uncertainty in each number is 1, what is the percent uncertainty in each? (c) Which is a more meaningful way to express the accuracy of these two numbers, significant figures or percent uncertainties?
1. 99 has 2 significant figures. 100 has 1 significant figure, although it's a bit ambiguous since perhaps it has 2 or maybe 3 depending on whether the zeros are considered significant. I assume 100 has 1 significant figure since it should otherwise be written in scientific notation to indicate if it has more than one.
2. $\%\textrm{unc}_{99} = 1\%$
$\%\textrm{unc}_{100} = 1\%$
3. % uncertainty is usually a more meaningful way of expressing uncertainty since it puts the uncertainty in perspective by comparing it with the measurement.
Solution Video