Chapter 1:Unit 10. Significant Figures

Significant figures are digits in a measurement that are known with certainty plus one digit of uncertainty.

Number of sig. fig= all certain + one uncertain digit

Determining Rule:

1. In any measurement, all nonzero digits are significant.
2. Zeros in between two nonzero(captive) digits are significant
3. Leading zeros (zeros to the left of the first nonzero digit) are never significant.
4. Trailing zeros (zeros to the right of last nonzero digit) only significant if there is a decimal point.

Example: 3.2072 has 5 sig. fig.

0.0000007 has only 1 sig. fig.

630 has 2 sig fig but 630.0000 has 7 sig fig. All the zeros are significant in the second case.

Questions:

1. For each of the following measurements, give the number of significant figures present and the uncertainty associated with the measurement.

727. 23
728. 1051
729. 230
730. 647,000,000

Ans:a. 5, b. 7 c.6, d.12

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