Just one sec...
Hey! Sign in to get help with your study questionsNew here? Join for free to post

Confusing question help

Announcements Posted on
Take our short survey, £100 of Amazon vouchers to be won! 23-09-2016
    • Thread Starter
    Offline

    0
    ReputationRep:
    Question: Calculate the uncertainty in the resistance of a bulb. The equation is R=V/I and the following measurements were taken:
    Potential Difference = 1.1 V
    Current = 0.4 A
    Online

    3
    ReputationRep:
    (Original post by XtrJ)
    Question: Calculate the uncertainty in the resistance of a bulb. The equation is R=V/I and the following measurements were taken:
    Potential Difference = 1.1 V
    Current = 0.4 A
    This question is checking whether you understand the connection between uncertainty and the number of significant figures used.

    1.1 V has 2sf
    0.4 A has 1 sf - so it could be anywhere between 0.350 and 0.449

    trailing zeros AFTER the decimal point *are significant figures* - if you measured the current to higher precision you could write 0.40 (i.e. 2sf) which would mean it was between 0.395 and 0.404

    the rules for combining uncertainties at A level are in stonebridge's sticky http://www.thestudentroom.co.uk/show....php?t=2661762

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  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
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: September 20, 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.

Poll
How do you eat your pizza

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

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