Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    1
    ReputationRep:
    Name:  3.jpg
Views: 8
Size:  78.7 KB
    How to work it out? I've no idea.
    Offline

    3
    ReputationRep:
    The best thing to do is to just think of the voltmeters as 10MΩ resistors, as that's all they're doing in this situation. You can also treat R and V2 as a single resistor by using the formula for resistors in parallel Name:  resistance.png
Views: 13
Size:  1.5 KB

    If V1 has 4V, this means that the voltages are being shared in a 2:1 ratio between V1 and the R/V2 parallel bank. This means the ratio between their resistances must also be 2:1, so the total resistance of R and V2 must be half of the resistance of V1 (5V).

    This gets you  \frac{1}{5M\Omega} = \frac{1}{R} + \frac{1}{10M\Omega} which you can solve to get R=10MΩ
 
 
 
  • 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
    Did TEF Bronze Award affect your UCAS choices?
  • 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.