Fundamental quantities are those which cannot be defined in terms of other quantities.

Physical constants are not affected by the choice of units.

Significant figures are counted excluding leading zeros but including trailing zeros after the decimal point.

Derived quantities are formed by combining fundamental quantities.

Significant figures represent the precision of the measured quantity.

Instrumental errors are caused by the limitations of the measuring devices.

Systematic errors occur consistently in one direction due to factors like faulty equipment.

Angular displacement is a measure of the angle through which an object has rotated, and its SI unit is derived from the radian.

The total reading combines the main scale and Vernier scale readings.

Significant figures indicate precision, excluding leading zeros.