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

    12
    ReputationRep:
    (Original post by liverpool2044)
    ah okay so negatives travel in opposite direction to the positive? is this similar in electric fields?

    which travel with the force and opposite the field
    Yes, a negative charge moving to the right for example has to be treated as a positive charge moving to the left.

    Electric field lines show you the direction a positive charge would move if it was placed in that field.
    Offline

    3
    ReputationRep:
    Is the electric field always the negative of the potential gradient?
    Offline

    2
    ReputationRep:
    How many repeated questions will there be in the MC?


    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    What does it mean about the radial to non radial thing? Does someone mind drawing exactly what is required? thanks
    Attached Images
      
    Offline

    1
    ReputationRep:
    Anyone got any tips for being fast (ish) on the multiple choice? I just did one and only answered 12.....
    Offline

    12
    ReputationRep:
    (Original post by Nikhilm)
    What does it mean about the radial to non radial thing? Does someone mind drawing exactly what is required? thanks
    Hmm, they are both positive point charges. Imagine when there electric fields meets, what's going to happen to the lines? Their radial pattern will change.
    Offline

    12
    ReputationRep:
    (Original post by Throor)
    Anyone got any tips for being fast (ish) on the multiple choice? I just did one and only answered 12.....
    Keep doing past papers, it honestly really helps with the timing.
    Offline

    3
    ReputationRep:
    (Original post by particlestudent)
    Hmm, they are both positive point charges. Imagine when there electric fields meets, what's going to happen to the lines? Their radial pattern will change.
    It wouldn't change to non radial though? I think they're talking about the back end of the charges but I'm not 100%, hence requesting someone to draw a diagram
    Offline

    12
    ReputationRep:
    (Original post by Nikhilm)
    It wouldn't change to non radial though? I think they're talking about the back end of the charges but I'm not 100%, hence requesting someone to draw a diagram
    Take a look at this diagram to give yourself an idea of what they mean. Modify that diagram to suit the magnitude of the charges they used.
    Attached Images
     
    Offline

    3
    ReputationRep:
    (Original post by particlestudent)
    Take a look at this diagram to give yourself an idea of what they mean. Modify that diagram to suit the magnitude of the charges they used.
    Ah thanks!
    Offline

    12
    ReputationRep:
    (Original post by Nikhilm)
    Ah thanks!
    No problem .
    Offline

    1
    ReputationRep:
    Name:  image.png
Views: 154
Size:  83.8 KBCan somebody explain to me why this one is C?
    Offline

    12
    ReputationRep:
    (Original post by CD1998)
    Name:  image.png
Views: 154
Size:  83.8 KBCan somebody explain to me why this one is C?
    It is moving parallel to the field so it won't experience a force.

    No force means no acceleration so no change in speed.
    Offline

    12
    ReputationRep:
    Can someone please help me? Q24 june 13 section A. I get the emf bit but not the direction. Thanks
    Attached Images
     
    Offline

    3
    ReputationRep:
    (Original post by particlestudent)
    Yes, a negative charge moving to the right for example has to be treated as a positive charge moving to the left.

    Electric field lines show you the direction a positive charge would move if it was placed in that field.
    thank youuu
    Offline

    2
    ReputationRep:
    Multiple Choice section seems ok now after 5 past papers


    Posted from TSR Mobile
    Offline

    12
    ReputationRep:
    (Original post by Yo12345)
    Multiple Choice section seems ok now after 5 past papers


    Posted from TSR Mobile
    Which papers have you done?
    Offline

    2
    ReputationRep:
    (Original post by particlestudent)
    Which papers have you done?
    Jan 2010 - Jan 2012 at home. Just need to do June 12 and Jan 13 tomorrow and June 2013 on Sunday. June 2014 and 15 as mocks. What about you?


    Posted from TSR Mobile
    Offline

    2
    ReputationRep:
    http://prntscr.com/bhq9df

    Answer is B

    I'm failing to see why the answer isn't D. If the magnet is decelerating once it enters the coil (due to Lenz's law) surely this means that the lines of flux cut per second decreases from a given value to zero.

    Edit: nvm I think I got it. I might have been getting confused with rate of change of flux linkage and simply flux linkage, i.e. the explanation is that the flux linkage rises from 0 to a value as it enters the field, creating a rate of change and thus inducing emf (causing a current reading to be displayed), but then that change stops occurring, so there's no more induced emf
    Offline

    1
    ReputationRep:
    (Original post by ¡Muy bien!)
    Can someone please help me? Q24 june 13 section A. I get the emf bit but not the direction. Thanks
    Magnetic flux=BA
    Area which the rod moves through= length * distance covered
    (where distance covered, d, equals velocity * time taken, from v=s/t)
    Magnetic flux equals BLvt, emf induced equals the rate of change of flux density.
    Therefore EMF=BLvt/t, the t's cancel, so the emf=BLv.
 
 
 
  • 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
    Brexit voters: Do you stand by your vote?
  • 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

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