what do you mean by zero error in a measuring instrument
Answers
Sometimes there is a mechanical error in vernier calliper (measuring instrument) due to which the zero mark of the vernier scale does not coincide with the zero mark of the main scale when the two jaws are in contact.It is then said to have zero error.
Zero error in a measuring instrument means that the instrument which is used for measurement is perfect and it measures everything precisely without any uncertainty.
1)Remember that whenever we see the term error written in the results of an experiment it does not mean that the instrument is bad and their is error in it.
2)Error simply means uncertainty in results for example when we measure the height of an object we can say that the height of the measured object is 10m with an uncertainty of (+)(-) 2m which means that the measured height could be less or more in height by 2m.This uncertainty is known as error.
3)An important point to understand is that whenever we make a measurement and we don't know about the error (uncertainty) in the measurement then doing the measurement is of no use.
4)Their is uncertainty (error) in every measurement.we cannot completely overcome it but yes we can always make it less and so less that it can be assumed that the measurement is perfect and without error