Error, uncertainty, precision and accuracy.

Question no. 6
Define the terms error, uncertainty, precision and accuracy.

ERROR:
DEFINITION:
"The difference between the measured value and the actual value of a measured physical quantity is called error."
EXPLANATION:
Error can not be less than the least count of the measuring instrument.
There are three types of errors in the measurement of physical quantities: personal, systematic and random.
There are certain kinds of errors that can not be removed.

UNCERTAINTY:
DEFINITION:
"The error arising due to the natural imperfections of the experimenter, the limitations of the apparatus and changes in the environment during the experiment is often called uncertainty."
EXPLANATION:
It is described as the error in the measurement.
There is always an uncertainty in the measurement.
It is used to express the uncertainty.

PRECISION:
DEFINITION:
"The term precision stands for magnitude of the error in the measurement."
EXPLANATION:
Precision of measurement is determined by the instrument being used.
Precise measurement is the one which has less absolute uncertainty.
The smaller the physical quantity, the more precise the instrument should be.

ACCURACY:
DEFINITION:
"Accuracy stands for the relative error. It is defined as the error divided by the quantity measured."
EXPLANATION:
It depends on the fractional and percentage uncertainty in that measurement.
Accurate measurement has less fractional or percentage uncertainty.