Q.Write any two errors of systematic errors. Explain them.

The uncertainty in any measurement is called an error, and errors fall into three fundamentally different categories.

i) Systematic errors -- reproducible, always biased in the same direction, from a problem that persists throughout the experiment:

1. Instrumental errors -- an instrument not correctly calibrated at manufacture (e.g. a metre scale with a worn-out end); fixed by careful instrument choice/calibration.
2. Imperfections in experimental technique/procedure -- limitations in the experimental arrangement itself, e.g. radiation losses from a poorly-insulated calorimeter; fixed with proper technique or applied corrections.
3. Personal errors -- caused by the individual observer: incorrect initial setup, or carelessness/lack of precaution while taking a reading.
4. Errors due to external causes -- changing external conditions (temperature, humidity, pressure) during the experiment bias the result.
5. Least count error -- set by the instrument's resolution (its smallest measurable increment, the least count); reduced only by switching to a higher-precision instrument.

ii) Random errors -- unpredictable, chance fluctuations in experimental conditions (pressure, temperature, voltage supply) or in the observer's own repeated readings (e.g. successive screw-gauge readings of a wire's thickness coming out slightly different each time). Because they are genuinely random rather than biased in one direction, they are reduced -- not eliminated -- by taking many readings and computing the arithmetic mean, taken as the best available estimate of the true value. …