# The length of rod is exactly 1 cm. An observer records a reading of 1.00 cm and 1.000 cm. Which is the most accurate measurement? Why?

## Expert Answers

Since the actual length is 1cm, both results are accurate.

If the measurement is given as 1.00cm, the observer is stating that the actual length l is in the interval `0.995"cm"<=l<=1.005"cm" ` ; in other words the measurement is accurate to the nearest hundredth of a cm (or nearest mm.) The actual length could be as much as .5mm from the given measurement.

If the measurement is given as 1.000cm, the observer is stating that the actual measurement is in the interval `0.9995"cm"<=l<=1.0005"cm" ` .

Thus in a sense, 1.000cm is more accurate than 1.00cm as the possible interval for the actual value is smaller.

## See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Further Reading

Approved by eNotes Editorial Team