What is Personal Error, Instrumental Error and Random Error? Explain with giving an example?

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PERSONAL ERROR :- These errors arise due to individual's bias, lack of proper setting of apparatus or individual's carelessness in taking observations without observing proper precautions, etc. E.g., when an observer holds his head towards right (by habit), while reading a scale, he intriduces some error due to parallex.

INSTRUMENTAL ERROR :- These errors occur due to the inbuilt defect of the measuring instrument. E.g., ewearing off the meter scale at one end, etc.

RANDOM ERROR :- The errors which occur irregularly and at random, in magnitude and direction, are called random errors. E.g., sudden rise in temperature or voltage while taking readings, etc.