Question

What do you mean by significant figures?

Answer 1

Hint: Before the definition of significant figures. We must know the accuracy or precision of measurement. In measurement, the level of correctness compared to the original value is termed as accuracy and the reliability and the consistency of a measurement of an experiment is the precision.

Complete step-by-step answer:
Number of digits in a value which contributes the level of accuracy of the value is called significant figures. The number of significant figures expresses the precision of a calculated value by a chemist or an engineer.
Now we must know when the digits are called significant.

1)Non-zero digits are significant
2) Between non-zero digits if zeros are present. Then these zeros are significant
3) Final zeroes in the decimal portion are significant only.

There are certain rules in determination of significant figures in a value. All non-zero digits in a value are significant. For example, in 245 three significant figures as 3 non-zero digits present and in 0.02 only one significant figure present as only one non zero digit, that is, 2 present.

Note: We have to be careful in determining significant figures of values containing zero. The significant figures for values containing zeroes depend on the position of zeroes.
1) If zeros are present before non-zero digits, then these zeros are not significant. For example, in 0.0054, only two significant figures were present.
2) Between two non-zero digits if zeroes present, then the zeros are significant. For example, in 1.0052, five significant figures were present.
3) Zeroes at the end of a decimal are also significant. For example, in 0.4000, four significant figures are present.