# Significant figure

## Main Question or Discussion Point

1. I read on my physics book that "zeros located at the end of a number are not significant if they are not followed by a decimal point." it also gave an example: 3000 K, in this case, there is only 1 significant figure. However, the number 93,000,000 m, on my book it says only the first five digits are significant. But i think there are only 2 significant figures according to the previous definition? I was confused.
2. What does 'size' mean in Physics? means the surface area?
3. The time it takes to play a CD in your stereo. My teacher said the answer was 3.6 kilosecond. but i didn't get it.

Thanks a lot.

Related Other Physics Topics News on Phys.org
1. theres only 2 sig figs
2. lots of things
3. 60s X 60min = 1 hour = 3600 seconds

how old are you?

Doc Al
Mentor
1. I read on my physics book that "zeros located at the end of a number are not significant if they are not followed by a decimal point." it also gave an example: 3000 K, in this case, there is only 1 significant figure. However, the number 93,000,000 m, on my book it says only the first five digits are significant. But i think there are only 2 significant figures according to the previous definition? I was confused.
That's certainly not consistent usage. If five significant figures are meant, it should be written as: 9.3000*10^7 or 93.000*10^6, etc.
2. What does 'size' mean in Physics? means the surface area?
"Size" is not a specific physics term. It could mean all sorts of things, depending on context.
3. The time it takes to play a CD in your stereo. My teacher said the answer was 3.6 kilosecond. but i didn't get it.
The prefix "kilo" means 1000. Figure out how many minutes that is.

jtbell
Mentor
3.6 kiloseconds? That's a short CD by my standards!

I get it now, thanks.