Final answer:
There are four significant figures in 100.0 and one in 100. Percent uncertainties, calculated at 1.01% for 99 and 1% for 100, provide a more meaningful expression of the measurements' accuracy than significant figures.
Step-by-step explanation:
The question is asking how many significant figures are there in the numbers 100.0 and 100. For the number 100.0, there are four significant figures because the zeroes after the decimal point count as significant figures. This indicates that the measurement is precise to the tenths place. In contrast, the number 100 only has one significant figure since trailing zeroes in a whole number without a decimal point are not considered significant.
Percent uncertainty can be calculated by dividing the uncertainty by the measured value and then multiplying by 100 to get the percentage. For the number 99 with an uncertainty of 1, the percent uncertainty would be (1/99) x 100 = 1.01%. For the number 100 with the same uncertainty, the percent uncertainty would be (1/100) x 100 = 1%.
When discussing which is a more meaningful way to express the accuracy, percent uncertainties provide a clearer understanding of the relative uncertainty of a measurement, regardless of the scale of the measurement, as compared to significant figures.