Final answer:
Each balance reading demonstrates a specific precision level based on significant figures. The smallest digit in each balance, such as in 1.019 g or 101.20 g, is an estimate that represents the degree of uncertainty in the measurement based on the balance's precision.
Step-by-step explanation:
Reading the following balances with precision and based on rules involves understanding significant figures and the precision of measuring devices. In this case, the balances are 1.019 g, 1.195 g, 101.20 g, and 11.2 g. Each of these balances indicates the level of precision the balance can measure to.
For example, a balance that reads 1.019 g is precise to the thousandths place, implying that the smallest variation it can detect is 0.001 g. Similarly, for the balance that reads 101.20 g, the precision is to the hundredths place, indicating that the uncertainty is ±0.01 g in the measurement.
The concept of significant figures is crucial in these measurements. Every digit in these measurements is considered significant, including the uncertain last digit, which is an estimate.
For instance, when measuring an object on a scale that is precise to the nearest tenth of a gram, such as 11.2 g, the actual mass could be anywhere between 11.15 g - 11.24 g. The displayed number, 11.2 g, includes the uncertain estimated digit, and the true value of the mass has an uncertainty of ±0.1 g.