How many significant figures are in each of the following?

Question

How many significant figures...am i right?
a) 0.02670 my answer-4?
b.) 328.0 my answer-4?
c.) 7000.0 my answer-1?
d.) 0.00200 my answer-3?

Answer 1

I agree with all your answers except c.

Since the rest are correct, I think you'll see why c is wrong if you think about it.

OK, fine, since other people seem to be disagreeing with me, I'll explain why I think c should be 5. See if you agree.

The rules of significant digits (from http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson23.htm) are:

- Digits from 1-9 are always significant.
- Zeros between two other significant digits are always significant
- One or more additional zeros to the right of both the decimal place and another significant digit are significant.
- Zeros used solely for spacing the decimal point (placeholders) are not significant.

Now if c were just 7000, I would agree that the answer would be 1.

But the 3rd rule says that zeros to the right of the decimal point and also to the right of a significant digit are significant. Since the last zero is to the right of the decimal, AND to the right of 7, which is significant, I think it should be considered significant. If so, then all the 0s between it are also significant, by the second rule.

I'm willing to admit I'm wrong if someone shows me evidence that this line of thinking is incorrect.

Answer 2

The first answer is correct.
Your answers are correct except for c)
c.) 7000.0 my answer-1?
7000.0 has 5 significant figures because every zero after a dot and between a number an a dot counts as a s.f.

Answer 3

I think you are absolutely right. Here is my reference, which agrees with your results:

When are Digits Significant?

Non-zero digits are always significant. Thus, 22 has two significant digits, and 22.3 has three significant digits.

With zeroes, the situation is more complicated:

1. Zeroes placed before other digits are not significant; 0.046 has two significant digits.
2. Zeroes placed between other digits are always significant; 4009 kg has four significant digits.
3. Zeroes placed after other digits but behind a decimal point are significant; 7.90 has three significant digits.
4. Zeroes at the end of a number are significant only if they are behind a decimal point as in (c). Otherwise, it is impossible to tell if they are significant. For example, in the number 8200, it is not clear if the zeroes are significant or not. The number of significant digits in 8200 is at least two, but could be three or four. To avoid uncertainty, use scientific notation to place significant zeroes behind a decimal point:

8.200 ´ 103 has four significant digits

8.20 ´ 103 has three significant digits

8.2 ´ 103 has two significant digits

Answer 4

the answer to this question is b. nicely, you're good in debating that it will be b or c because they do have 3 important figures. besides the indisputable fact that, the superb perfect answer is b by way of 10^-2. 10^-2 signifies that you bypass the decimal position 2 places to the right interior the unique quantity. in case you're taking the quantity on your question and turn it to three important figures and then bypass the decimal 2 places to the right, you receives b. to make sparkling, in case you want to be secure, it should be more beneficial to positioned it into medical notation kind.

Answer 5

a) 4
b) 4
c) 5 (The only one you missed. 7000.0 ≠ 7000 as far as you need to consider significant digit.)
d) 3

Answer 6

You're answers are correct except for c.
Which is has 4 SF

Answer 7

a)4
b)3(do not count the .0)
c)1
d)3

Answer 8

a) 4
b) 3
c) 1
d) 3

Answer 9

4,3,4,4

Answer 10

4,4,5,3