You are Here: Home >< Physics

# Percentage uncertainty/ absolute error?

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
1. How would you work this out?

For the first one: isn't it 1/3.5x10^3 then x100. Since the ruler is 1m. I don't get why you would convert it to cm because 3.5x10^3 is in meters. Shouldn't Units be the same ?

But the answer is supposed to be 2.9%.
2. I have my mock tomorrow so please can someone try to help?
3. Hi,

So, the percentage uncertainty is worked out by ((uncertainty)/value *100) and the uncertainty in this case, since the readings have not been repeated, is the precision of the value given, which is the smallest lines per metre you can measure - 0.1*10-3,

and that divided by 3.5*10-3 *100 would = to 2.9%! (2s.f. at most for uncertainties)

Hope that helped! It's quite hard to explain
4. (Original post by grace_zzz)
Hi,

So, the percentage uncertainty is worked out by ((uncertainty)/value *100) and the uncertainty in this case, since the readings have not been repeated, is the precision of the value given, which is the smallest lines per metre you can measure - 0.1*10-3,

and that divided by 3.5*10-3 *100 would = to 2.9%! (2s.f. at most for uncertainties)

Hope that helped! It's quite hard to explain
Yes, it helps thanks. How would you calculated the absolute uncertainty?
5. (Original post by Questioness)
Yes, it helps thanks. How would you calculated the absolute uncertainty?
(Percent uncertainty/100)*Value

(3.5&10^-3)*(2.9/100)=Absolute uncertainty

Might be a bit late :s
6. (Original post by Dieselblue)
(Percent uncertainty/100)*Value

(3.5&10^-3)*(2.9/100)=Absolute uncertainty

Might be a bit late :s
Alright thanks .

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 22, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

### How to get a 1st class degree

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.