The record of any measurement is done by using a number that includes all the digits those are known reliably plus one digit that is uncertain. The reliable digits plus the one uncertain digit are known as significant figures or significant digits of the measurement.

Significant figures indicate the precision of any measurement and thus it depends on the least count of the measuring device.

For example, if a distance is measured with scale having least count in millimeter (mm), a length of 20.6 centimeter (cm) has three significant figures 2, 0 and 6. The digit 2, 0 are certain while the digit 6 is uncertain. Thus, 20.6 cm means the length is 20.60 cm ± 0.5 mm (0.05 cm) i.e., it lies between 20.55 cm and 20.65 cm.

<< Back | Next >>