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Some of the important considerations in the process of
measurement are described here.
Accuracy : By Employing a suitable tool a measure of a
physical quantity can be known. The reading's accuracy depends on two
factors. The device as well as the person who takes the measurement.
Therefore accuracy can mean the degree up to which a measured value
conforms with a standard or true value.
Least Count : A measuring instrument's accuracy depends upon
its least count. Least count of the instrument is the least distance
which it can measure accurately.
Measuring instruments such as vernier callipers, micrometer, screw
gauge, etc. show different levels of accuracy in comparison to each
other. For example the least count of a screw gauge is 0.01mm while that
of a vernier calliper is 0.1mm.
Significant Figures : Significant figures refer to those
digits about which we are perfectly sure of plus those digits about
which we are not that sure. However, they have a value which is
meaningful. This also gives insights concerning the extent of
uncertainty in measurement. To give an example the value of p (pi) is
3.1415926 = circumference/diameter Generally the experiments show answer
upto 3.14 while the balance digits can vary due to alteration in the
value adopted for circumference and diameter and that's why there is
rounding off to 3 digits.
Sensitivity of the Instrument : TSensitivity of the
instrument refers to the instant reaction of an instrument, indicating
the measurement at a particular instance of use
Hysteresis : The measuring instrument should be devoid of any
prior recording or reading, and must give identical values for ascending
or descending readings.
Precision : Precision refers to the degree to which a given
set of measurements of the identical amount concur with their mean
value, but which will not be true value.
Errors : Error is the difference that exists between the true
value and the measured value. There are many types of errors, some of
which are given here.
