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    (Original post by Patrick Gekko)
    yes
    I haven't been able to revise properly until tonight due to FP3 and S2 as well so I'm so far behind. Any ideas what to focus on? I'm so so screwed
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    (Original post by arrow_h)
    Could you possibly outline this for me?
    Gas cloud
    - large dense gas and dust cloud at a few kelvin ( cold ) starts to collapse
    - this could be due to gravity, shock waves from supernovae, ect.

    protostar
    - gas collapses and heats up
    - gravitational energy to heat
    - microwave and IR produced
    - 2000-3000k

    (T-Tauri phase)

    Main sequence
    - fusion of hydrogen to helium
    - star stable
    - about 90% of lifetime in this stage

    subgiant - red giant
    -hydrogen runs out
    -core shrinks
    -collapse causing temperature to increase
    -fusion of heavier elements
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    (Original post by cjlh)
    I haven't been able to revise properly until tonight due to FP3 and S2 as well so I'm so far behind. Any ideas what to focus on? I'm so so screwed
    I have no idea. I don't have a clue what special relativity is about so I'm probably going to focus on that
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    (Original post by cjlh)
    Anyone doing Turning Points feel like they're ****ed? the mark schemes are soo specific
    I agree. The mark scheme per kg is quite significant.
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    (Original post by TajwarC)
    Formation:
    -stars formed in gas clouds such as nebulae
    -the dust particles are attracted towards eachother by gravity
    -they form a clump which heats up as it gets more massive
    -eventually forming a protostar
    -as the core heats up, hydrogen can fuse into helium, this is when the star is a main sequence star
    -the outward pressure of the large amounts of energy released by hydrogen fusion prevents the star from collapsing under its own gravity

    Formation of a Red Giant
    -the hydrogen in the core beings to run out. As the Hydrogen to helium core burning stops, the star expands and the outer layers (shells) cool down (this is when the star becomes red)
    -the core heats up enough to allow helium to oxygen and carbon core burning.
    -Hydrogen to helium shell burning occurs.
    -Once the helium in the core runs out, Helium to oxygen and carbon shell burning occurs.
    -In lower mass stars the core will not heat up to allow any more fusion so it contracts under its own gravity (this is eventually stopped due to electron degeneracy pressure) and into a white dwarf where it will continue to cool and fade away

    -In a large star the gravity will cause it to contract more than in the above example (electron degeneracy pressure cannot prevent more contraction in this case) and will cause an explosion i.e. a supernova.
    -leaving behind a black hole or neutron star


    pls be on the spec I didn't memorise all of that for nothing lmao
    It is on the spec

    "Stellar evolution: path of a star similar to our Sun on the Hertzsprung-Russell diagram from formation to white dwarf "
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    (Original post by Patrick Gekko)
    I have no idea. I don't have a clue what special relativity is about so I'm probably going to focus on that
    Ah I think I'm okay with that it's all of the experiment specifics that seem to be getting me. Absolutely PRAYING for a kind paper but not expecting it. Gonna be feeling violated leaving the exam hall I can tell

    (Original post by Anonymoose12)
    I agree. The mark scheme per kg is quite significant.
    Woah the banter is flying!
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    (Original post by Mentalmirz)
    It is on the spec

    "Stellar evolution: path of a star similar to our Sun on the Hertzsprung-Russell diagram from formation to white dwarf "
    Thanks

    Seeing as it hasn't been asked before I imagine there is a decent chance it will come up
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    (Original post by Mentalmirz)
    Gas cloud
    - large dense gas and dust cloud at a few kelvin ( cold ) starts to collapse
    - this could be due to gravity, shock waves from supernovae, ect.

    protostar
    - gas collapses and heats up
    - gravitational energy to heat
    - microwave and IR produced
    - 2000-3000k

    (T-Tauri phase)

    Main sequence
    - fusion of hydrogen to helium
    - star stable
    - about 90% of lifetime in this stage

    subgiant - red giant
    -hydrogen runs out
    -core shrinks
    -collapse causing temperature to increase
    -fusion of heavier elements
    It doesn't appear to be anywhere on the spec so fingers crossed
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    (Original post by cjlh)

    Woah the banter is flying!
    You seem pretty excited about the banter. Maybe calm yourself down a bit and you might emit a photon.
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    (Original post by marcusman97)
    It doesn't appear to be anywhere on the spec so fingers crossed
    "Stellar evolution: path of a star similar to our Sun on the Hertzsprung-Russell diagram from formation to white dwarf"
    that is from the spec but I've never seen it on past papers
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    Feel pretty unprepared for this
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    (Original post by 1017bsquad)
    Heycan you help me on question 1 aii) I was thinking of using theta = R/d, with R being 1 AU and d with the distance provided, but this results in an incorrect answer, isn't that what I'm supposed to do for parallax? I really don't understand why the mark scheme used s = r*theta

    Question: http://prntscr.com/blswf1
    Answer:http://prntscr.com/blswku
    I dont think this is parallax. You have used the correct formula from the front of the formula booklet () but the arc length will be the diameter of Vesta which is and the radius will be the distance between the earth and vesta which is .

    So you rearrange for theta which is arc length / radius. So:
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    Heat pump/Refrigirators I literally don't get it
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    (Original post by ememoville)
    Heat pump/Refrigirators I literally don't get it
    What don't you get?
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    Turning point in physics anyone????
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    (Original post by Mentalmirz)
    "Stellar evolution: path of a star similar to our Sun on the Hertzsprung-Russell diagram from formation to white dwarf"
    that is from the spec but I've never seen it on past papers
    I saw it I think on a legacy paper, basically you just have to draw an arrow from main sequence to red giant to white dwarf on the diagram
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    (Original post by raman_17)
    Turning point in physics anyone????
    me (y)
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    (Original post by raman_17)
    Turning point in physics anyone????
    Unfortunately
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    (Original post by splashywill)
    -thermionic emission
    -magnetic lens - condenses electron been towards sample
    -(sample)
    -objective lens - deflects and inverts scattered electrons
    -(Inverted first image)
    -microscopic lens- focuses on centre of first image and inverts into high resolution final image
    -(final image)

    -limitations
    - Thickness of the sample can cause the electron beam to slow down therefore reducing de broglie wavelength and worsening resolution
    - uneven thickness of sample can cause different amounts of diffraction for electron beam therefore making the distorting final image.

    (I did this mainly for my own revision... but this is pretty much all you need to learn about them)
    Fancy quickly summarising the tunnelling microscope?
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    Could somebody explain 2cii) in this one please? http://filestore.aqa.org.uk/subjects...A-QP-JUN13.PDF
 
 
 
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