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Edexcel IAL Physics Unit 3 WPH03 May June 2016 Discussion watch

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    (Original post by Blazyy)
    I put in parallax error when placing the pins, is that also correct?
    ummmmm, what do you mean by pins?
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    (Original post by Hamadtype-)
    My gradient was 5, my resistivity was 1.23*10^-6
    Exact same

    What did you write for the "comment on safety" for the refractive index experiment?

    Also for the how to find refractive index question i wrote
    Refractive index = Sin I / Sin r
    Take a reading of angle of incidence and refraction from the graph
    Multiply them by sin and divide to find refractive index

    Is that correct?
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    (Original post by Blazyy)
    I put in parallax error when placing the pins, is that also correct?
    Nevermind, ignore my question
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    (Original post by Ali Bizri)
    Exact same

    What did you write for the "comment on safety" for the refractive index experiment?

    Also for the how to find refractive index question i wrote
    Refractive index = Sin I / Sin r
    Take a reading of angle of incidence and refraction from the graph
    Multiply them by sin and divide to find refractive index

    Is that correct?
    I put: draw a graph of sin 1 against sin r and calculate the gradient which will give you the refractive index. For safety, I said don't point the ray box towards yours and others' eyes as the laser can damage your eyes,
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    (Original post by Blazyy)
    Nevermind, ignore my question
    If you mean put the pins along the refracted ray, then yeah it makes sense that there would be a parallex error there.
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    (Original post by Ali Bizri)
    Exact same

    What did you write for the "comment on safety" for the refractive index experiment?

    Also for the how to find refractive index question i wrote
    Refractive index = Sin I / Sin r
    Take a reading of angle of incidence and refraction from the graph
    Multiply them by sin and divide to find refractive index

    Is that correct?
    For safety I wrote low voltage

    but for refractive index calculation they asked for graphical calculation, so you had to say draw a graph of sin i on sin r and find gradient
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    (Original post by Hamadtype-)
    Yeah, But the second and third point was out of the best fit line
    I got a value of 4.91 fr gradient! :/
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    (Original post by don't cry-craft)
    I put: draw a graph of sin 1 against sin r and calculate the gradient which will give you the refractive index. For safety, I said don't point the ray box towards yours and others' eyes as the laser can damage your eyes,
    That makes sense, the answers should be identical for both methods so I don't think it'll be a big deal, for safety i said that this is a low risk experiment and i added one more point which was the risk of falling block so wear foot protection.
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    (Original post by Hamadtype-)
    Parallax error for protractor lol
    how can there be a parallax error since the protractor would be flat against the paper to measure the angle?
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    (Original post by Hamadtype-)
    For safety I wrote low voltage

    but for refractive index calculation they asked for graphical calculation, so you had to say draw a graph of sin i on sin r and find gradient
    What did you write to "comment on her plan" when she measured the time as 3s for a trolley to go down a slope?
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    It should be on your eye level horizontally , like you need to make your eyes directly parallel to the measurement, some people can stand away from the protractor and count.
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    (Original post by Sunethra)
    What did you write to "comment on her plan" when she measured the time as 3s for a trolley to go down a slope?
    I wrote there would be human reaction time error, so an electronic timer would be better for accurate results.
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    (Original post by Hamadtype-)
    It should be on your eye level horizontally , like you need to make your eyes directly parallel to the measurement, some people can stand away from the protractor and count.
    I said parralex errors when using protractor and I said other rays might be incident on the glass block so in brackets I said do the experiment in a dark room
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    (Original post by Hamadtype-)
    I wrote there would be human reaction time error, so an electronic timer would be better for accurate results.
    yeah same, especially since 3s is a very short amount of time.
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    (Original post by Sunethra)
    What did you write to "comment on her plan" when she measured the time as 3s for a trolley to go down a slope?
    I measured the persentage uncertainty by doing 0.38/3 *100 and found about 12.5% and commented that it is too high
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    (Original post by Sunethra)
    I said parralex errors when using protractor and I said other rays might be incident on the glass block so in brackets I said do the experiment in a dark room
    Oh okay, I said that there's an uncertainty of 0.5 degrees when taking the readings, especially since the angles can be quite small. Would this be okay?
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    Guys my value for resistivity was 4.6x10^-6? i think i did something wrong when finding the area of the wire but my gradient was 4.5? i thing im out of the range of what they would expect
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    hey my exam was good. is the graph supposed to be a straight line or a curvy type of thing.
    if i used the right method to find gradient and the value of resistivity but got the wrong answer will i get any marks.
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    (Original post by Hamadtype-)
    ummmmm, what do you mean by pins?
    Sometimes when you don't have a ray box in hand, you use pins to mark the incident and refracted ray.
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    (Original post by Suhaib.134)
    Guys my value for resistivity was 4.6x10^-6? i think i did something wrong when finding the area of the wire but my gradient was 4.5? i thing im out of the range of what they would expect
    did u convert the diameter to radius? Gradient was 4.96 i think so when u round it would be 5 not sure if urs was right.
 
 
 
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