Question

How many significant figures are in the measurement 0.0034 kg?

Answer 1

Two significant figures.

Explanation:

For starters, you should know that non-zero digits are always significant.

So right from the start, you know that this measurement has at least two significant figures, `3` and `4`.

`0.0034 ->` two non-zero digits `=` two sig figs

Now, are the zeroes significant as well?

The answer is no. The reason is that zeroes that come after the decimal point are only significant if the number is greater than `1` or if they are sandwiched between two non-zero digits for numbers that are smaller than `1`.

`color(red)(color(black)(1.)00color(black)(34)` `->` the zeroes are significant because they follow the decimal point for a number that is `>1`

`0.1color(red)(00)34 ->` the zeroes are significant because they are sandwiched between two non-zero digits for a number that is `<1`

In your case, you have a number that is smaller than `1` and the two zeroes are not sandwiched between two non-zero digits, hence they are not significant.

Therefore, your measurement will have `2` significant figures, the two non-zero digits.