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AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread] Watch

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    (Original post by _Caz_)
    Tbh CD223 deserves a medal. What ever grades you all get, it is because of CD223 answering all your queries.

    Respect.

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    Thanks Caz - I don't do it for the medals really


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    (Original post by mrno1324)
    What's the point of the 97% U-238 in fuel rods if it's not fissionable?
    If you had pure U235 in a clump at critical mass that's what is colloquially known as a nuclear bomb
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    Why is it that the doppler effect never come up?
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    you only need 3% u235 becuase otherwise **** would get nasty.
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    Could anyone explain the twin paradox doing turning points?


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    How can you work out which star is closer to the Earth given absolut & apparent magnitude and temperature?
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    (Original post by Jimmy20002012)
    Could anyone explain the twin paradox doing turning points?


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    We don't need to know it just that time goes slower for the moving object


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    How I did the question:

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    Has anyone got any tips on energy (heat specifically) transfer questions? I always seen equations in the mark scheme along the lines of: Heat supplied by X = Heat gain by mateiral Y + heat dissipated by Z. But I struggle forming these equations.
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    (Original post by Protoxylic)
    Are the neutrons bounded to anything? They are just neutrons so they have a binding energy of zero
    cheers
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    (Original post by EconFan_73)
    Anyone know how to do 4b on last year's Astrophysics paper?

    Basically says distance to stars measured using angle of parallax method to a precision of 0.002 arc seconds. Calculate the maximum distance measurable?

    Mark scheme shows use of d=1/p....?
    distance is 1/angle in arc seconds. so 1/0.02 gives 500 parsecs, which you convert to meters.
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    (Original post by johnh545)
    Anyone?
    Basically what this means is that for every 400 emitted rays the detecter only detects 1 of them. For example if the source emitted 800, the detector would detect 2.
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    for the equation r = r0 A1/3 is r0 always 1.4 x 10-15 m or will they give you a value depending on the question in the exam?
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    hey can anyone explain question 3b(i) on this paper...

    http://filestore.aqa.org.uk/subjects...1-QP-JUN12.PDF


    i don't understand why they are using area of a sphere and why the radius of that sphere is then 0.18
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    What is r0 in the nuclear equation? Book says 1.05 fm but wiki says 1.25fm...
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    What do we want the 6 marker to be tomorrow?

    And does anyone have a link to a good set of Applied notes?
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    (Original post by Disney0702)
    for the equation r = r0 A1/3 is r0 always 1.4 x 10-15 or will they give you a value depending on the question in the exam?
    I just asked that a few seconds after you!

    book says 1.05fm, do they give you a value in the exams?
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    Name:  68cccfb74c5459516b69fb8077e20b2a.png
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    Attachment 430659430667


    Why is the mass of hydrogen 1.00728?
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    (Original post by ubisoft)
    I just asked that a few seconds after you!

    book says 1.05fm, do they give you a value in the exams?
    (Original post by Disney0702)
    for the equationr = r0 A1/3 is r0 always 1.4 x 10-15 m or will they give you a value depending on the question in the exam?
    I don't think we're expected to know a value, we'll be given one/given information to calculate it in the exam I think.
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    Hey can anyone explain why you multiply by 0.5 for question 4(a)(i)
    http://filestore.aqa.org.uk/subjects...C-QP-JUN12.PDF

    Thanks
 
 
 
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