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    path difference is nX for wavelength = X
    for wavelength = X/2, path difference also = nX i believe
    nX = 2n(X/2) as if nX is constant and X is halved then n must double to keep nX constant if you get me?
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    ahhh yh I get u, thanks pretty hard question...
    (Original post by chrishannon09)
    path difference is nX for wavelength = X
    for wavelength = X/2, path difference also = nX i believe
    nX = 2n(X/2) as if nX is constant and X is halved then n must double to keep nX constant if you get me?
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    (Original post by philo-jitsu)
    Applying for physics at Lancaster....if I hadn't have blagged stats revision and got 55ums (yup) this year would be way less stressful....I'm basically either getting a b or a*.....m1 didn't help.

    Feel like all the exams are way more bunched up this year....I've got c3&4 physics 4 and bio 5 in the same weeks...gonna be fun

    What you applying for?
    I got into Lancaster with a grade below what they wanted for PPE last year, don't stress too much
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    And good luck today everyone!
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    (Original post by philo-jitsu)
    Applying for physics at Lancaster....if I hadn't have blagged stats revision and got 55ums (yup) this year would be way less stressful....I'm basically either getting a b or a*.....m1 didn't help.

    Feel like all the exams are way more bunched up this year....I've got c3&4 physics 4 and bio 5 in the same weeks...gonna be fun

    What you applying for?
    ah nice man! i applied for mech eng at Southampton, yeah ahah i got like 52 ums in S1 ahah, so i gunna resit it this year, did you resit c1 or c2?
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    Im stressing so much for this exam!
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    (Original post by TSRPAV)
    ah nice man! i applied for mech eng at Southampton, yeah ahah i got like 52 ums in S1 ahah, so i gunna resit it this year, did you resit c1 or c2?
    No...i got 95 in c1 and 76 in c2....last years c2 was aweful....come to think of it i should have resat c2 as it would probably be easy having done a2....

    Didnt want to resit stats as there is no crossover with other units....regret it now!!

    Having looked at the unnoficial mark scheme for m1 i pretty much have to get 94 ums in c3 and c4...its doable but under exam pressure i make really dumb errors so we shall see
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    (Original post by Gapyearstudent54)
    I got into Lancaster with a grade below what they wanted for PPE last year, don't stress too much
    Makes me feel slightly better lol....i might be being stupid but what is ppe?
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    Whoever mentioned optic fivres saved me....been meaning to look over it again....what is path dispersion? Is it due to interference or energy loss from collision with boundary?
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    (Original post by philo-jitsu)
    Whoever mentioned optic fivres saved me....been meaning to look over it again....what is path dispersion? Is it due to interference or energy loss from collision with boundary?
    This would result in different light rays merging and the signal being disrupted
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    (Original post by Exams987)
    This would result in different light rays merging and the signal being disrupted
    Thanks alot....but what actually causes path dispersion?
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    (Original post by philo-jitsu)
    Makes me feel slightly better lol....i might be being stupid but what is ppe?
    Politics, philosophy and economics

    I ended up not going because I didn't actually want to study it 😂 But I still got the offer, and I think it's quite a popular course
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    (Original post by philo-jitsu)
    Thanks alot....but what actually causes path dispersion?
    Light rays being refracted at different angles and thus being different speeds, and so the signal is distorted.
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    (Original post by philo-jitsu)
    Thanks alot....but what actually causes path dispersion?
    the thinner the core is the less likely for path dispersion to occur
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    (Original post by philo-jitsu)
    Thanks alot....but what actually causes path dispersion?
    Is ut to do with various wavelengths....travel at different velocities so by the end of the fibre a signal may be slightly delayed causing incorrect information transfer?

    Which is why they try to use almost perfectly monochromatic light?...isnt monochromatic light easy to accomplish? Or when we get given lasers for experiments are they only 'almost' mono but not perfectly?
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    (Original post by philo-jitsu)
    Is ut to do with various wavelengths....travel at different velocities so by the end of the fibre a signal may be slightly delayed causing incorrect information transfer?

    Which is why they try to use almost perfectly monochromatic light?...isnt monochromatic light easy to accomplish? Or when we get given lasers for experiments are they only 'almost' mono but not perfectly?
    I believe it's because different pulses of light take slightly different paths down the optical fibre meaning that they travel different distances and so arrive at the end of the fibre at different times, so the pulse is reduced in intensity and slightly longer
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    (Original post by philo-jitsu)
    Is ut to do with various wavelengths....travel at different velocities so by the end of the fibre a signal may be slightly delayed causing incorrect information transfer?

    Which is why they try to use almost perfectly monochromatic light?...isnt monochromatic light easy to accomplish? Or when we get given lasers for experiments are they only 'almost' mono but not perfectly?
    you are talking about spectral dispersion

    that is different to path dispersion , they are not the same thing
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    thoughts for 6 marker anybody? would be great to hear some possible questions
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    Ah okay....so essentially the direction of each ray from the source is slightly different so subsequent reflection angles vary so path varies?

    Thanks to both who helped
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    Its the last ever exam so they could get creative with the 6 marker....or like my teacher says as they are working on the new spec they may get lazy and just use questions theyve already done.....dont think it helps guessing just try and be ready for everything!
 
 
 
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