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!! Physics HL LC '16 - Predictions, guesses, discussion, etc.

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    #122
    adam240610
    Registered Users Posts: 815 ✭✭✭adam240610


    DownOneTourist wrote: »
    any one get seven images for that light question?
    The niagara falls question was very interesting! Letting mph equal mc delta theta seemed insane but it worked.
    I was going for a b1 but think i got a b2.

    That was how you got height, very weird indeed.

    I got 3.39 so 3 images on mine, you had to work out D from lines per mm which I'd say most people probably had an error in it, did a question last night that was the same question backwards so was handy haha.


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    #123
    DownOneTourist
    Registered Users Posts: 182 ✭✭DownOneTourist


    adam240610 wrote: »
    That was how you got height, very weird indeed.

    I got 3.39 so 3 images on mine, you had to work out D from lines per mm which I'd say most people probably had an error in it, did a question last night that was the same question backwards so was handy haha.
    I go 3.39 also. but only for one side. I multiplied that by 2 then added 1 because there is also an image in the middle.


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    #124
    Seaaan
    Registered Users Posts: 626 ✭✭✭Seaaan


    DownOneTourist wrote: »
    I go 3.39 also. but only for one side. I multiplied that by 2 then added 1 because there is also an image in the middle.

    I left it as n=3 but clearly stated that 3 on either side of zero order just to be safe.

    As for Q1 my clockwise and anti clockwise moments balanced, with maybe .01 of a difference, was that right?


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    #125
    DownOneTourist
    Registered Users Posts: 182 ✭✭DownOneTourist


    Seaaan wrote: »
    I left it as n=3 but clearly stated that 3 on either side of zero order just to be safe.

    As for Q1 my clockwise and anti clockwise moments balanced, with maybe .01 of a difference, was that right?

    q1 was bad for me!! and i'm counting it... I hate moments


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    #126
    alaandocs
    Registered Users Posts: 33 ✭alaandocs


    Seaaan wrote: »
    I left it as n=3 but clearly stated that 3 on either side of zero order just to be safe.

    As for Q1 my clockwise and anti clockwise moments balanced, with maybe .01 of a difference, was that right?

    Mine was out .101 for the moments. I'd say I'm wrong but don't know yet. I didn't include the weight of the stick in that one , only the weights up and down.


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    #127
    Seaaan
    Registered Users Posts: 626 ✭✭✭Seaaan


    DownOneTourist wrote: »
    q1 was bad for me!! and i'm counting it... I hate moments

    I practiced it a lot lately as it was due; got fairly lucky on wavelength one though because it was the first experiment I did in fifth year so I remember it well..

    Q4 though, was that temperature vs resistance for a thin metallic conductor? (Glycerol and water bath) As in a straight line graph from a bit up on y axis? Was a sneaky little question..


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    #128
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    Seaaan wrote: »
    I left it as n=3 but clearly stated that 3 on either side of zero order just to be safe.

    As for Q1 my clockwise and anti clockwise moments balanced, with maybe .01 of a difference, was that right?

    In past exams they would accept 3, 6 or 7. So any of those would get full marks


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    #129
    adam240610
    Registered Users Posts: 815 ✭✭✭adam240610


    Seaaan wrote: »
    I practiced it a lot lately as it was due; got fairly lucky on wavelength one though because it was the first experiment I did in fifth year so I remember it well..

    Q4 though, was that temperature vs resistance for a thin metallic conductor? (Glycerol and water bath) As in a straight line graph from a bit up on y axis? Was a sneaky little question..

    Yeah was a straight line, I used glycerol and a hot plate, same difference haha.
    It was a small slope though, but I can't imagine the slope affecting a rough sketch too much


    n=3 is what I left it as, surprised it didn't come out as like 3.7 to catch people on rounding.


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    #130
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    adam240610 wrote: »
    Yeah was a straight line, I used glycerol and a hot plate, same difference haha.
    It was a small slope though, but I can't imagine the slope affecting a rough sketch too much


    n=3 is what I left it as, surprised it didn't come out as like 3.7 to catch people on rounding.

    That's be an awfully nasty thing to do in a stressful exam tbh.

    In an exam like the LC you'll get full marks for that, well you SHOULD. Depends on the marking scheme. Given that the majority of the cohort found the exam difficult you'll be grand.

    Do papers usually go live at about 6pm?


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    #131
    adam240610
    Registered Users Posts: 815 ✭✭✭adam240610


    TMJM96 wrote: »
    That's be an awfully nasty thing to do in a stressful exam tbh.

    In an exam like the LC you'll get full marks for that, well you SHOULD. Depends on the marking scheme. Given that the majority of the cohort found the exam difficult you'll be grand.

    Do papers usually go live at about 6pm?

    Morning ones normally up a bit earlier.
    You won't, wouldn't in maths, and wouldn't here. Can't wait to open my envelope in august to see what I got haha


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    #132
    Caoimh1997
    Registered Users Posts: 4 ✭Caoimh1997


    Does anyone remember what they got for the velocity of the daughter nucleus roughly? For Q12a)


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    #133
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    adam240610 wrote: »
    Morning ones normally up a bit earlier.
    You won't, wouldn't in maths, and wouldn't here. Can't wait to open my envelope in august to see what I got haha

    I did the LC last year, I remember the marking schemes. They were usually very kind to people


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    #134
    alaandocs
    Registered Users Posts: 33 ✭alaandocs


    TMJM96 wrote: »
    In past exams they would accept 3, 6 or 7. So any of those would get full marks

    What did you finish with if you don't mind me asking? If you don't want to say then it's ok


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    #135
    adam240610
    Registered Users Posts: 815 ✭✭✭adam240610


    Caoimh1997 wrote: »
    Does anyone remember what they got for the velocity of the daughter nucleus roughly? For Q12a)

    I can barely remember that question but O want to say it was in the region of 50000 m/s? No idea


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    #136
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    alaandocs wrote: »
    What did you finish with if you don't mind me asking? If you don't want to say then it's ok

    What grade did I get did you mean? I only got a B2 in the end, due to having a bad day. Got an A2 in the mocks if I recall correctly. Doing Physics in college and have gotten As in all my Physics modules in first year so, it gets better I guess :rolleyes:

    I'd only accept 7 as the answer, as that's the right answer, if that's what you mean :o


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    #137
    wick___
    Registered Users Posts: 2 ✭wick___


    What a weird paper lol


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    #138
    bookworm20
    Registered Users Posts: 38 ✭bookworm20


    I got zero for the velocity of the daughter nuclei


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    #139
    alaandocs
    Registered Users Posts: 33 ✭alaandocs


    TMJM96 wrote: »
    What grade did I get did you mean? I only got a B2 in the end, due to having a bad day. Got an A2 in the mocks if I recall correctly. Doing Physics in college and have gotten As in all my Physics modules in first year so, it gets better I guess :rolleyes:

    I'd only accept 7 as the answer, as that's the right answer, if that's what you mean :o

    Fair play, you doing it in trinity or where?


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    #140
    adam240610
    Registered Users Posts: 815 ✭✭✭adam240610


    bookworm20 wrote: »
    I got zero for the velocity of the daughter nuclei

    Pretty sure that's impossible with conservation of momentum and all that


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    #141
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    alaandocs wrote: »
    Fair play, you doing it in trinity or where?

    Nope, UL! I did all the wrong subjects for the LC (mostly humanities, Physics was my only Science) so I didn't get as high points as I probably could have with the three lab sciences.

    I'm not really a fan of Trinity anyway plus you don't get a B.Sci, you get a BA (nothing wrong with a BA, just if I'm doing Science I want a B.Sci!). This type of talk is for another type of thread. Don't want to derail ye!


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    #142
    bookworm20
    Registered Users Posts: 38 ✭bookworm20


    Whats was the maximum angular dispalcement for the pendulum? I got 5
    What distance above earths surface was the pendulum in q6? I got one thousand and something
    What isotope of actinium does radium-225 decay to?
    How would u produce coherent sources? I said the sun?? (idk)
    How did you find max and min tension in q12c?


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    #143
    alaandocs
    Registered Users Posts: 33 ✭alaandocs


    TMJM96 wrote: »
    Nope, UL! I did all the wrong subjects for the LC (mostly humanities, Physics was my only Science) so I didn't get as high points as I probably could have with the three lab sciences.

    I'm not really a fan of Trinity anyway plus you don't get a B.Sci, you get a BA (nothing wrong with a BA, just if I'm doing Science I want a B.Sci!). This type of talk is for another type of thread. Don't want to derail ye!

    True we better leave that there


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    #144
    bookworm20
    Registered Users Posts: 38 ✭bookworm20


    adam240610 wrote: »
    Pretty sure that's impossible with conservation of momentum and all that

    ur right, just figured it out thx


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    #145
    Caoimh1997
    Registered Users Posts: 4 ✭Caoimh1997


    I was running out of time so I said the velocity of the daughter nucleus was the same as the velocity of the alpha particle from the first part, to conserve momentum but I'm probably wrong...


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    #146
    alaandocs
    Registered Users Posts: 33 ✭alaandocs


    bookworm20 wrote: »
    Whats was the maximum angular dispalcement for the pendulum? I got 5
    What distance above earths surface was the pendulum in q6? I got one thousand and something
    What isotope of actinium does radium-225 decay to?
    How would u produce coherent sources? I said the sun?? (idk)
    How did you find max and min tension in q12c?

    The isotope would be 225 actinium as its beta decay. 225Ra88=225Ac89+0e-1
    = are instead of the arrow


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    #147
    bookworm20
    Registered Users Posts: 38 ✭bookworm20


    alaandocs wrote: »
    The isotope would be 225 actinium as its beta decay. 225Ra88=225Ac89+0e-1
    = are instead of the arrow

    cool thats what i got too


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    #148
    BrownTrout
    Closed Accounts Posts: 216 ✭✭BrownTrout


    bookworm20 wrote:
    Whats was the maximum angular dispalcement for the pendulum? I got 5 What distance above earths surface was the pendulum in q6? I got one thousand and something What isotope of actinium does radium-225 decay to? How would u produce coherent sources? I said the sun?? (idk) How did you find max and min tension in q12c?

    Didn't do 6,

    Actinium 225,

    Coherent sources by putting the same gaseous element into two different discharge tubes (guess)


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    #149
    DownOneTourist
    Registered Users Posts: 182 ✭✭DownOneTourist


    I got lead for an isotope somewhere in the paper


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    #150
    Caoimh1997
    Registered Users Posts: 4 ✭Caoimh1997


    I think coherent light sources can be got by shining a monochromatic light source through young's slits, as it's a diffraction grating with two slits in it. Could be wrong but that's what I put


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    #151
    TMJM96
    Registered Users Posts: 228 ✭✭TMJM96


    Caoimh1997 wrote: »
    I think coherent light sources can be got by shining a monochromatic light source through young's slits, as it's a diffraction grating with two slits in it. Could be wrong but that's what I put

    You're right with that. A division of wave front where wavefront is divided into two parts by reflection, refraction or diffraction and those two parts reunite at a small angle to produce interference as done in case of your Young's double slit experiment!


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