Explain, giving examples, the errors that occur while making measurements.
Error = Actual value − Measured value
Systematic errors are those errors which occur according to a certain system. These errors are due to known reasons. These errors can be minimized by locating the source of error.
Systematic errors can be classified into the following four main categories:
(i) Instrumental errors: Occurs when the instrument used for measurement is faulty.
(ii) Personal errors: Occurs due to the carelessness of the observer, or due to the habits and peculiarities of the observer.
(iii) Errors due to external sources: These errors occur due to the change in external conditions like temperature, pressure, wind etc.
(iv) Errors due to internal sources: These errors are due to limitations of experimental arrangement. For example, the loss of energy due to radiation causes errors in calorimetric readings.
These errors are due to one or more than one of the following reasons:
(i) Improper setting of the instrument
(ii) Recording of observations wrongly
(iii) Not to take into account the sources of error and precautions
(iv) Using some wrong value in calculations
These errors take place in a random manner and are called random errors. These errors depend on the error in the measuring process and also on the individual measuring person.
Precision and accuracy:
Precision refers to the closeness of various measurements for the same quantity and accuracy refers to the argument of a particular value to the true value of the result.
For example the value of pie is 22/7=3.1428….
If we use the value of pie as 3.15 or 3.14, etc, it will be termed as precise but if we use the value as 3.1428, the value would be said to be accurate.