Sig Fig Clarification: 150. vs 150 - Is it Correct?

  • Thread starter dnt
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In summary, when dealing with significant figures, it is important to consider the accuracy of the given numbers. For example, if a question asks for the volume of a box with dimensions of 85 m by 92 m by 95 m, the answer should be reported as 7.4 x 10^5 m^3 since each number has 2 significant figures. The decimal at the end of a number can also affect the number of significant figures, as seen in the difference between 150. and 150.0. It is recommended to use scientific notation to avoid confusion and accurately represent the number of significant figures.
  • #1
dnt
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just to clarify on sig figs...for example if a question asked what is the volume of a box that is 85 m by 92 m by 95 m, the answer is 742900 m^3 but since each number has 2 sig figs, the answer must be reported as 740,000 m^3?

is that correct?

also, 150 has 2 sig figs but 150. has 3...right?

thanks.
 
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  • #2
dnt said:
just to clarify on sig figs...for example if a question asked what is the volume of a box that is 85 m by 92 m by 95 m, the answer is 742900 m^3 but since each number has 2 sig figs, the answer must be reported as 740,000 m^3?

is that correct?

also, 150 has 2 sig figs but 150. has 3...right?

thanks.

You've got it.
Actually, it's probably better form to write it as:
[tex]7.4 \times 10^{5}[/tex]
Since that will leave no doubt about whether the zeros are significant.
 
  • #3
thanks.

regarding the "150 vs 150." - i know how many sig figs it has but can someone explain WHY the decimal at the end makes the 0 significant in 150. compared to only 150?
 
  • #4
150. is read as 150.0
 
  • #5
whozum said:
150. is read as 150.0
umm..i don't think so, i think 150.0 has four sig figs, 150. has three, and 150 two.



dnt, the decimal in 150. is just a way of saying that, to the limits of your measuring tool, for example: this stick is exactly 150. metres , not 149, not 151, but 150.
and in the case of 150.0, it would be implied that your measuring tool can measure to the tenth of a metre and for example you could say: this stick measures exactly 150.0 meters, not 150.1 not 150.2, but 150.0, though you know nothing about the second decimal place. it could be 150.01, 150.0[1-9], u don't know, its too precise for ur measuring tool. u get it?
 
  • #6
It would, of course, be better to write them as 1.5 x 102 if you intend 2 sig figures, 1.50x102 if you intend 3, 1.500x102 if you intend 4.
 
  • #7
DB said:
umm..i don't think so, i think 150.0 has four sig figs, 150. has three, and 150 two.

i didnt say it IS 150.0, it is understood as 150 and nothing else. exactly 150, it has 3 significant figures.
 
  • #8
sorry, i missunderstood ur statement
 

1. What are significant figures?

Significant figures, also known as significant digits, are the digits in a number that carry meaning and contribute to its precision. These digits are used to indicate the accuracy of a measurement or calculation.

2. How do I determine the number of significant figures in a number?

The rules for determining significant figures are as follows:

  • Non-zero digits are always significant.
  • Any zeros between two significant digits are significant.
  • Leading zeros are not significant.
  • Trailing zeros after a decimal point are significant.
  • Trailing zeros before a decimal point may or may not be significant, depending on the measurement or calculation.

3. What is the difference between "150." and "150" in terms of significant figures?

The addition of a decimal point at the end of a number indicates that all the trailing zeros are significant. In the number "150.", there are three significant figures, while in "150", there are only two significant figures.

4. Is it correct to use "150." or "150" in scientific calculations?

It depends on the precision needed for the calculation. If the measurement or calculation is known to the hundredth place, using "150." would be more accurate. However, if the measurement or calculation is only known to the tenth place, using "150" would be sufficient.

5. Can significant figures affect the accuracy of a scientific result?

Yes, significant figures play a crucial role in indicating the precision and accuracy of a scientific result. Using the correct number of significant figures in calculations can help avoid errors and ensure the accuracy of the final result.

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