We need to understand the concept of “significant figures” because measurements need to be recorded in a proper way.
Here is an example to make
things easier to understand:
You must be knowing that ruler, vernier calipers and micrometer screwguage all measure length. However they measure length to different amount
|Vernier calipers||10th of a millimeter
|Micrometer screwguage||100th of a millimeter
Let’s say the actual diameter of a wire is 2.012 millimeters.
So if you measure the diameter of a wire using a ruler, you may record the value as 2mm but not 2.0mm because the ruler will not tell you about the tenth
of a millimeter.
Similarly, if you use vernier calipers, you may write the measurement as 2.0mm but you should not write 2.01mm because vernier calipers cannot
measure accurately a hundredth of a millimeter.
In the same way the recorded value from a micrometer screwguage shall be 2.01mm.
Next step: Identifying significant figures