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    How did you find it?
    I hope that something similar will come up tomorrow.

    I only have the paper, not the markschemes
    Can you post your answer to q 1) c) i tried to find some info on the net, but all explanations were too deep for 3 marks...
    Also what did you get for resistance in q 2)b)ii), i get 8.33 ohms
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    im working on 2b the explanation... will post my answer to part two wen i do it...
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    using the time constant, 37%of 102^-3 is 37.74^-3 the appropriate time is then 20^-3

    4700^-6 X R = 20^-3

    therefore R = 4.3 ohms?

    plz correct me if im wrong... am prone to making silly errors
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    can someone with a markscheme post the answer for Q1 part C for june 2002 phy6?

    Outline briefly how a Van de Graaff generator can accelerate electrons to very high energies.
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    (Original post by zoidberg)
    can someone with a markscheme post the answer for Q1 part C for june 2002 phy6?

    Outline briefly how a Van de Graaff generator can accelerate electrons to very high energies.
    I havent got the markscheme... but would you like me to give it a go anyway?
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    sure, its 3 marks. i know how a VDG generator works but just cant think of how to explain it to be worth that much in that context
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    ok here goes:

    The earthed needle places electrons on the belt, which subsequently makes the belt negatively charged. This charge is then removed at the top by electrons flowing off a different needle into the sphere. Consequently, the charge builds up as more and more electrons are added to the sphere until the rate of addition of electrons equals the rate of removal of electrons through insulation leaks etc. There is a filament which is connected to the sphere, which results in it becoming negatively charged too. Once the charge has built up to a certain level, electron are ejected from this filament and are repelled by the negative charge of the sphere, consequently resulting in the acceleration of the ejected electrons to very high energies.

    how is that for ya?
    some feedback would be nice to know where i would lose the marks in ur opinion
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    sounds good, when you say the electrons are ejected is that through a spark? that's all i associate van der graaffs being any use for

    thx
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    (Original post by zoidberg)
    sounds good, when you say the electrons are ejected is that through a spark? that's all i associate van der graaffs being any use for

    thx
    lol... in this case i dont think it would be seen as a spark... i think it would be just like in an CRT...
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    hmm the diagram still confuses me, the filament thing connected to the van der graaff, doesnt that just provide the accelerating force and doesnt actually emit electons? i thought the electron gun did that.
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    (Original post by zoidberg)
    hmm the diagram still confuses me, the filament thing connected to the van der graaff, doesnt that just provide the accelerating force and doesnt actually emit electons? i thought the electron gun did that.
    yeah you are right... why is that filament there then? the sphere does most of the accelerating force...
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    if you look on the jan04 paper... they have the same diagram but without the filament (but its the positive one)... confusing :s
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    hmm confusing, oh well if it comes up again tomorrow should be able to bumble through enough to get a few marks
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    (Original post by zoidberg)
    hmm confusing, oh well if it comes up again tomorrow should be able to bumble through enough to get a few marks
    yup thats the mentality
    most people dont need high marks in this anyway
    i think 60% should guarantee me an A
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    yeah me too hopefully, got a high 90% for as and as far as i know did ok on phy4/5. hardly done any revision for tomorrow, dont really know what there is to revise, most of the questions you can just make educated guesses at and theres quite a lot of easy marks on maths/base units crap
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    (Original post by zoidberg)
    yeah me too hopefully, got a high 90% for as and as far as i know did ok on phy4/5. hardly done any revision for tomorrow, dont really know what there is to revise, most of the questions you can just make educated guesses at and theres quite a lot of easy marks on maths/base units crap
    same AS mark as me
    i got 74/90 in phy4 in jan... i was 80% sure i fcked up completely in that... must have been some good scaling I should get a bottom A or high B for phy5 as it was easy well practical was hard... redid phy2... got 74/90 1st time around... should get 80+ this time
    why do they make physics soo easy
 
 
 
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