Significant Figures

The precision of an experimental result is implied by the number of digits recorded.

Rules:

  1. The leftmost nonzero digit is the most significant digit.
  2. If no decimal point: the rightmost nonzero digit is the least significant digit.
  3. If decimal point: the rightmost digit (even if zero) is the least significant digit.
  4. All digits between the most and least significant digits are significant digits.

Example:

Measured value Number of significant figures Remarks
2 1
2.0 2
2.00 3
0.136 3
2.483 4
2.483 x 103 4
310 2 Ambiguous. the zero may be significant or it may only be present to show the location of the decimal point.
3.10 x 102 3 No ambiguity.
3.1 x 102 2