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OCR PHYSICS B G495~ 18th June 2015 AM ~ A2 Physics Watch

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    (Original post by Cerdic)
    Here are all the formulas you'll need at A2 that aren't on the formula sheet although some are implied. (That's a direct .docx (Microsoft Word 2007+ file) download from TSR).
    Can you save as pdf please


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    Hey
    Um I am having some issues with the advanced notice stuff...

    Wave length is inversely proportional to resolution right?
    A smaller wavelength gives a better resolution.

    But why?

    Thanks in advance chicks!
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    As the probe size got smaller, the images became "sharper" because you were increasingly certain about the objects' shape. IMagine throwing marbles at an object compared to the throwing footballs at it

    Things with short wavelengths are like the marbles in that they can provide you with fairly detailed information about what they hit. The shorter the probe's wavelength is, the more information you can get about the target.
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    (Original post by Cerdic)
    Here are all the formulas you'll need at A2 that aren't on the formula sheet although some are implied. (That's a direct .docx (Microsoft Word 2007+ file) download from TSR).
    So happy I knew all these off by heart. Also knew how to derive them.
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    (Original post by Mutleybm1996)
    Can you save as pdf please


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    Edited my original post

    (Original post by ExMus)
    So happy I knew all these off by heart. Also knew how to derive them.
    Wow... Keen :laugh:
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    (Original post by Hubay)
    As the probe size got smaller, the images became "sharper" because you were increasingly certain about the objects' shape. IMagine throwing marbles at an object compared to the throwing footballs at it

    Things with short wavelengths are like the marbles in that they can provide you with fairly detailed information about what they hit. The shorter the probe's wavelength is, the more information you can get about the target.
    Thanks chick!!!
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    Np

    Unrelated but does anyone know where to find some good notes on ionising radiation and risk ?

    Can't get my head around it at all, thanks
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    (Original post by Hubay)
    Np

    Unrelated but does anyone know where to find some good notes on ionising radiation and risk ?

    Can't get my head around it at all, thanks
    There are some notes on the whole G495 syllabus here go to Page 39 for notes on Risk etc.
    http://www.johnbright.uk/depts/scien...20Revision.pdf
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    The above pdf is just this http://en.wikibooks.org/wiki/A-level...ing_Physics%29 condensed into one document. Easier to navigate the webpages, and also they have animations/gifs on them that have been cut out of the pdf.
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    Both of these are great, Thanks! :P
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    (Original post by physjim)
    haha married to my desk and revision at the moment
    Hahaha I have made myself a revision den - many pillows but no actual room to do any work yet...
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    Hey, does anyone have any helpful tips on revising G495, this unit just won't seem to stick in my brain

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    (Original post by tinyRaeesa)
    Hey, does anyone have any helpful tips on revising G495, this unit just won't seem to stick in my brain

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    Step 1: Past papers
    Step 2: Mark past papers and understand areas where you went wrong
    Step 3: Repeat steps 1 and 2
    Step 4: A/A*
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    I've been trying that but it doesn't seem to help :/ still hitting mediocre grades
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    I only know 2 people who aren't getting mediocre grades, one guys is autistic and is insanely clever and the other guy's dad works for Diamond light synchroton. as Cerdic said it's just a case of doing past papers i re write all of the pages from the text book in a condesed form. I've also made Cue cards for the more wordy answers, like how a transformer works and explaining what a change in pressure means.

    another set of questions ive found
    http://moodle.flintshire.gov.uk/hhs/...tions%20GN.pdf
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    I'll try that thank you
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    (Original post by tinyRaeesa)
    I've been trying that but it doesn't seem to help :/ still hitting mediocre grades
    Do you mark them yourself? And do you truly understand the things you didn't quite get? Papers are repetitive so you must make special effort to review all areas where you didn't hit the mark. The mark scheme also helps with knowing what kind of things they want for the explain questions.
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    (Original post by Cerdic)
    Do you mark them yourself? And do you truly understand the things you didn't quite get? Papers are repetitive so you must make special effort to review all areas where you didn't hit the mark. The mark scheme also helps with knowing what kind of things they want for the explain questions.
    Its mainly small things I'm not getting quite right. So it's not full topics just the small details that I seem to miss every time relating to each topic, so its hard to pin point exactly what I don't know.
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    Hey chick!
    Um set one, improving the view, question8, part e…
    Not sure how you worked this out!

    Imassuming the 5x10-12 is the wave length of the electron?
    Butwhat is the 250x10-9?

    I got 5x10-12/500x10-9= 1/100000
    So100000 times better
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    (Original post by Lissy14)
    Hey chick!
    Um set one, improving the view, question8, part e…
    Not sure how you worked this out!

    Imassuming the 5x10-12 is the wave length of the electron?
    Butwhat is the 250x10-9?

    I got 5x10-12/500x10-9= 1/100000
    So100000 times better
    Yeah you can assume 5pm is the wavelength or you can use your answer, a mark scheme will take both.

    The smallest detail that can be resolved by a microscope using normal light is

    R=\frac{0.61\lambda}{NA}

    but you can take this as the resolving power is just R=\frac{\lambda}{2} for this, so you would use 250\times10^-^9m as it's half the wavelength of the light.
    Non Latex in spoiler.
    Spoiler:
    Show

    Resolving power:
    R=0.61*lambda / NA

    Can assume:
    R=lambda/2

    So would use:
    250*10^-9 m
 
 
 
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