Difference between Instrumental and personal errors
Instrumental errors
- The errors which are introduced in the measurement due to faulty instruments are known as instrumental error.
- Instrumental errors can have zero error in the instrument.
- When the scale in any instrument is not calibrated properly so that the pointer of that instrument is above or zero value, which introduces zero error in the instruments.
- Instrumental error can avoid by calibrating the given instrument properly so that it do not have zero error or replacing them with the proper one.
- Instrumental error also can be avoided by adding the value of error in the observed reading, so that the corrected reading can be given as,
∴ Corrected reading = Observed value ± Zero error
Personal errors
- The errors which are introduced in the measurement due to faulty observations recorded by observer are known as personal error.
- Though the instruments are proper, arrangement made is also correct but due to carelessness of an observer these errors can be introduced.
- During measurement of current using ammeter, if observer doesn’t record it with the position of neck parallel to the pointer of scale, then the reading may be more or less.
- Personal errors can be avoided by taking measurement with careful readings and handling the setup carefully.