Hey there! Sign in to join this conversationNew here? Join for free

Confusing question help Watch

Announcements
    • Thread Starter
    Offline

    1
    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
    Offline

    19
    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
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Break up or unrequited love?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • 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.