Question

Which of the following is most precise?
A) $5.00\text{ mm}$
B) $5.00\text{ cm}$
C) $5.00\text{ m}$
D) $5.00\text{ km}$

Answer 1

Hint: Precision means the closeness of measured values. In order to measure a value precisely, we need the lowest scale possible to measure.

Complete step by step answer:
So in our question, we are given measurements in different scales. In order to measure the distance between two points, we can use any of these scales. But in order to get a precise measurement, we need to use the lowest scale. So in the options, the lowest used scale is the millimetre (mm), so the measurement with the millimetre scale will be more precise than any other scale.
So the answer to the question is option(A)- 5.00 mm.

Additional Information:
Precision and Accuracy: -
Precision means the closeness of the measured values. So if we do trials to measure a quantity and get values which are very close to each other in each trial, then the measurements are said to be very precise.
Accuracy of a value is the measure of the closeness to the original value. It shows how much the measured value varies with actual value.

Note: A measured value can be both precise and accurate, accurate and not precise, not accurate and precise or neither of them.
In order to strike a perfect balance between precision and accuracy for a measuring instrument calibration is needed. To calibrate an instrument, record how far off its measurements are from known or true values. Many measuring instruments need frequent calibration in order to work properly.