when an object was weightedon a top loading balance the balance display read 13.730 the mass was recorded as 13.73g what is wrong with that explain the answer

The mass of the object was known to five (5) significant figures but was recorded to only four (4). In other words, you threw away one significant figure.

There may be nothing wrong with recording the mass as 13.73 g if for example the next step determines the volume to 2 sig figs and the objective is to calculate the density, which would be to 2 sig figs.

I think the question setter is trying to get at recording the sig figs as displayed on the balance, then round as required.

Another thing is that we are not told that the balance is measuring in g, it might be in oz for example. So that the display shows 13.730 we have assumed that the display is in g.

The error in this case arises due to the precision of the measuring device. The top loading balance is displaying four decimal places, which implies a precision of 0.0001g. However, when the mass is recorded as 13.73g, it suggests a precision of only two decimal places.

To understand this better, let's go through the steps to determine the mass using the balance's display:

1. When an object is weighed on a top loading balance, the display shows the weight in grams. In this case, it shows 13.730g.

2. The display has four decimal places (e.g., 0.0001g precision). So, the measurement could be accurate up to the fourth decimal place.

3. However, when the recorded mass is stated as 13.73g, it suggests a rounded value with precision up to two decimal places (e.g., 0.01g precision).

4. Therefore, the inconsistency lies in reporting the mass with only two decimal places when the balance has a higher precision of four decimal places. This leads to a loss of the last two decimal places of accuracy.

In summary, rounding the measured value of 13.730g to 13.73g implies a lower precision than what the top loading balance is capable of providing. To maintain the correct precision and accuracy, the recorded mass should be 13.730g or rounded consistently using the balance's precision, such as 13.73g (if the balance only measures to two decimal places) or 13.7300g (if additional decimal places are desired).