Final answer:
When setting measurements with dials, importance lies in recognizing the precision of the measuring device and the rules for significant figures, such as non-zero digits always being significant and zeros being significant when confirmed by the measurement scale.
Step-by-step explanation:
When setting the desired measurement using dials, it is important to be aware of the precision of the measuring device as well as the conventions for determining which digits are significant in your measurement. For example, if a ruler shows both centimeter and millimeter markings, you can ascertain the measurement of an item to a more precise level with the millimeter markings, as you would be able to estimate to the nearest millimeter (mm) rather than just the centimeter (cm). Every nonzero digit is considered significant, but care must be taken with zeros – they are only significant if they are confirmed by the measurement (such as a 0 in the value 120 being significant if measured on a scale that measures to the nearest pound).
In the case of analog meters, such as those using a galvanometer, the dials will display a needle pointing to a scale. Current flow through the galvanometer causes needle deflection, and the precise position of the needle on the marked scale will determine the measurement. The significant figures in this type of reading depend on the minimum scale division that can reasonably be estimated by the observer.
Overall, it is critical to understand the level of precision that your measuring tools offer and to report the significant figures accurately to reflect the capability of the instrument and the certainty of your measurement.