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

OCR Physics B G495 Field and Particle Pictures June 21st 2011 Exam Thread watch

    Offline

    0
    ReputationRep:
    (Original post by Summerdays)
    The anser is 4.35

    For the realitivistic it was gamma = Erest + Ekinetic/Erest

    gamma = 1/root(1-v^2/c^2)
    I tried that! but whenever i rearranged to find v, the root was negative .. so couldn't do it, are you meant to just ignore negative or what? :s or am i completely in the wrong direction?

    I ended up getting a spare piece of paper and just writing a whole load of random things i could calculate with what i had in vain hope of getting some method marks haha
    Offline

    13
    ReputationRep:
    (Original post by arianex)
    800 plus 1/2? I thought it was 2d = nlambda...either way, something around the line of 500-ish nanometers for that laser?

    PS// Those prep Qs were gorge. Made Section C mostly dreamy. You = hero. ^^
    ~500nm was what I got. using lambda = 2d/800
    Offline

    15
    ReputationRep:
    What did people put for the effects on the amplitudes of OX and OY question by removing the air?
    Offline

    0
    ReputationRep:
    (Original post by arianex)
    800 plus 1/2? I thought it was 2d = nlambda...either way, something around the line of 500-ish nanometers for that laser?

    PS// Those prep Qs were gorge. Made Section C mostly dreamy. You = hero. ^^
    for minima isn't it nlambda/2 when n = odd number? so they interfere completely destructively and out of phase?
    Offline

    10
    ReputationRep:
    (Original post by arianex)
    800 plus 1/2? I thought it was 2d = nlambda...either way, something around the line of 500-ish nanometers for that laser?

    PS// Those prep Qs were gorge. Made Section C mostly dreamy. You = hero. ^^
    It said MINIMUM and for a minimum path difference = (n + 1/2)lambda
    But I could be wrong though, in this case. I guessed
    Offline

    10
    ReputationRep:
    (Original post by Geekchic17)
    for minima isn't it nlambda/2 when n = odd number? so they interfere completely destructively and out of phase?
    No it's (2n +1)lambda 2n +1 = odd
    Offline

    10
    ReputationRep:
    (Original post by Revolution is my Name)
    What did people put for the effects on the amplitudes of OX and OY question by removing the air?
    I made it up:

    I said remove air, density decreases and thus the refrative index decreases and thus less of the light becomes referacted and thus the phase difference between the phasors become more and more out of phase.
    Offline

    0
    ReputationRep:
    got ignore anyone know the phasors one in section c? n also how to find the mass of uranium per year or anything?
    Offline

    0
    ReputationRep:
    I need to stop reading this thread lol, I can see my grade slipping away.
    Offline

    0
    ReputationRep:
    (Original post by Summerdays)
    I made it up:

    I said remove air, density decreases and thus the refrative index decreases and thus less of the light becomes referacted and thus the phase difference between the phasors become more and more out of phase.
    wt to put in the arrow? omg i get this wrong i know
    Offline

    13
    ReputationRep:
    (Original post by Revolution is my Name)
    What did people put for the effects on the amplitudes of OX and OY question by removing the air?
    I said that the one related to the air would rotate.
    Offline

    10
    ReputationRep:
    (Original post by wki)
    wt to put in the arrow? omg i get this wrong i know
    The oppoite direction, I think
    Offline

    0
    ReputationRep:
    (Original post by Summerdays)
    I made it up:

    I said remove air, density decreases and thus the refrative index decreases and thus less of the light becomes referacted and thus the phase difference between the phasors become more and more out of phase.
    they were completely out of phase to begin with so they couldn't get more out of phase
    Offline

    0
    ReputationRep:
    (Original post by Geekchic17)
    I tried that! but whenever i rearranged to find v, the root was negative .. so couldn't do it, are you meant to just ignore negative or what? :s or am i completely in the wrong direction?

    I ended up getting a spare piece of paper and just writing a whole load of random things i could calculate with what i had in vain hope of getting some method marks haha
    Nah, definitely meant to get a positive root :/

    What equation did you end up with after you rearranged to find V?

    I think (can someone confirm this?) it was meant to be v = \sqrt{c^{2}(1-\gamma ^{2})}
    Offline

    0
    ReputationRep:
    (Original post by Summerdays)
    The oppoite direction, I think
    same here how to find the mass of uranium per year or anything?
    Offline

    1
    ReputationRep:
    (Original post by Kingbradley6)
    I think that's irrelevant? But if someone could explain their logic/calculations behind this question it would be appreciated.
    Hmm it probably is What I was trying to say though, is that only low-risk patients will get a scan. So low-risk patients, getting a very small amount of radiation.

    Anywho, I think we've had enough confirmation on here that it's 4.35. If that's too low then blame OCR
    Offline

    0
    ReputationRep:
    (Original post by ejw93)
    they were completely out of phase to begin with so they couldn't get more out of phase
    wt u reckon the ans will b ? i"ve totally no idea on this one
    Offline

    10
    ReputationRep:
    (Original post by ejw93)
    they were completely out of phase to begin with so they couldn't get more out of phase
    They were, before the air was put in front of one of the mirrors, I think?
    Offline

    15
    ReputationRep:
    Well, it asked to comment on the amplitudes, so I said that of OX (or whichever it was where they were removing the air) would increase because less was being refracted and so more reflected, and there'd be no change for OY. Then it said to mention the detector signal, and I think I guessed at their being more minima.
    Offline

    10
    ReputationRep:
    (Original post by jimmeh)
    Nah, definitely meant to get a positive root :/

    What equation did you end up with after you rearranged to find V?

    I think (can someone confirm this?) it was meant to be
    Yes, that's what I did.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

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.