Errors and Uncertainties

 

All physical measurements are uncertain or imprecise to some extent. 

It is very difficult to eliminate all possible errors or uncertainties in a measurement.

 The error may occur due to» 

1. negligence or inexperience of a person
2. the faulty apparatus
3. inappropriate method or technique.

Uncertainty:

                       The uncertainty may occur due to inadequacy or limitation of an instrument, natural variations of the object being measured or natural imperfections of a person's senses.

However, the uncertainty is also usually described as an error in a measurement. 

There are two major types of errors.

1. Random error
2. Systemic error

Random error is said to occur when repeated measurements of the quantity, give different values under the same conditions. It is due to some unknown causes. 

How to reduce Random? Repeating the measurement several times and taking an average can reduce then effect of random errors.

Systematic error refers to an effect that influences all measurements of a particular quantity equally. It produces a consistent difference in readings. It occurs to some definite rule. It may occur due to zero error of instruments, poor calibration of instruments or incorrect markings etc. 

Systematic error can be reduced by comparing the instruments with another which is known to be more accurate. Thus for systematic error, a correction factor can be applied.