| NOTE |
There can be some confusion regarding the trailing zeros. Suppose, a length is recorded as 4.700 m. It is evident that the zeros here are meant to convey the precision of measurement and are, therefore, significant. Now, suppose the unit of the number is changed, i.e,
Since the last number has trailing zeros in a number with no decimal, it can be concluded erroneously that the number has two significant figures, while in fact it has four significant figures. To overcome such ambiguities in determining the number of significant figures, measurements are to be reported in scientific notation. In this notation, Every number is expressed as a x 10b, where a is a number between 1 and 10, and b is any positive or negative exponent of 10. It is often customary to write the decimal after the first digit. The significant number of the base represents the significant number of the measurement. Thus, 4.700 m = 4.700 x 102 cm = 4.700 x 103 mm = 4.700 x 10-3 km Each number in this case has four significant figures. Thus, “a choice of change” of different units does not change the number of significant digits or figures in a measurement. |