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ANSWERS: OCR Physics B(Advancing Physics) G491~ 20th May 2014~ AS Physics Watch

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    50-45
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    I managed to finish all of the paper and check
    13.41%
    I managed to finish the paper but didn't check
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    I missed off a few of the questions
    37.80%
    I missed >half of the questions
    3.66%

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    (Original post by Robbo54)
    As we're the first year to not have January exams (ie: I would have taken G491 if we had January exams), will the grade boundaries change to reflect the extra 5 months of preparation?

    I'm hoping an A is ~45.
    Either higher due to prep or lower due to so many exams


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    (Original post by Mutleybm1996)
    Either higher due to prep or lower due to so many exams


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    What do you think a B would be? I'm definitely not going to get an A in physics, hopefully i can try to get a B even though I'm dropping Physics. Really scared for this exam; i've got 5 exams this upcoming week!
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    (Original post by kobobo)
    What do you think a B would be? I'm definitely not going to get an A in physics, hopefully i can try to get a B even though I'm dropping Physics. Really scared for this exam; i've got 5 exams this upcoming week!
    Well, 42/60 was the boundary for June 2013. That's what's it is normally at (70%).

    Who knows if OCR will lower/higher the grade boundaries. They always want the same number of people getting the same grades, each year.

    Me, too. I can never get full marks on the microstructure questions (eg: 8c on January 2010.) It's safe to say I'm most worried for this out of ALL my exams.
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    Can anyone explain this to me? It's question 11. (a) (ii) on the June 2010 paper.
    The question is: A sample is digitised....using a 16bit sampling rate. The maximum peak to peak signal voltage is 100mV. Show that the voltage resolution is less than 2uV.
    There is also a graph of p.d./mV over time.

    The mark scheme says:
    Resolution = (100x10^-3V/(2^16)-1)

    I don't understand where the minus 1 is coming from and I've never seen this equation before! Can anyone help?
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    Do we need to know about ultrasound?


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    (Original post by kobobo)
    What do you think a B would be? I'm definitely not going to get an A in physics, hopefully i can try to get a B even though I'm dropping Physics. Really scared for this exam; i've got 5 exams this upcoming week!
    ^?


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    Name:  ImageUploadedByStudent Room1400508728.380907.jpg
Views: 270
Size:  183.0 KB

    Do we have to know how to do this?


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    (Original post by urz13)
    Can anyone explain this to me? It's question 11. (a) (ii) on the June 2010 paper.
    The question is: A sample is digitised....using a 16bit sampling rate. The maximum peak to peak signal voltage is 100mV. Show that the voltage resolution is less than 2uV.
    There is also a graph of p.d./mV over time.

    The mark scheme says:
    Resolution = (100x10^-3V/(2^16)-1)

    I don't understand where the minus 1 is coming from and I've never seen this equation before! Can anyone help?
    No of alternatives = 2^16.

    Max number is 2^16 -1 (as you don't count 0.)

    For example, the max number you can count to with an 8 bit number is 255.
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    (Original post by Robbo54)
    No of alternatives = 2^16.

    Max number is 2^16 -1 (as you don't count 0.)

    For example, the max number you can count to with an 8 bit number of 255.
    Does this stem from log2(Vt/Vn) ?


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    (Original post by Mutleybm1996)
    Name:  ImageUploadedByStudent Room1400508728.380907.jpg
Views: 270
Size:  183.0 KB

    Do we have to know how to do this?


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    I think we need to understand the method, but it's very unlikely that they'll expectus to memorise the average number of lines on a page or something, since it came up recently.
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    (Original post by Mutleybm1996)
    Does this stem from log2(Vt/Vn) ?


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    I don't think so.

    Essentially it's the smallest change the equipment is capable of measuring.

    R = 0.01 (assuimg the equipment can measure to 2dp) / Sensitivity.

    Here's the wikibooks article
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    What structure do ceramics have?
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    This exam board is a piece of poop, the text books is like reading some flipping foreign text lol
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    (Original post by 9876cd)
    What structure do ceramics have?
    Aren't ceramics amorphous - so they have really random(non directional bonds) structure patterns with more than one different sized atom thingys, in a lattice??
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    (Original post by 9876cd)
    What structure do ceramics have?
    1.) Strong covalent/ionic bonds (directional) -> Strong
    2.) Rigid lattice -> stiff
    3.) No glide (as rigid structure and amorphous) -> Brittle.
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    Do we need to know about ultrasound?


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    How much percentage is each of the different sections of the total AS grade? All I know is coursework is 20%


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    I kinda need help on materials, the stuff on plastic flow and crack propagation
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    (Original post by Andromeda2.5)
    How much percentage is each of the different sections of the total AS grade? All I know is coursework is 20%


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    The specification says that 491 is 30% (60 marks) and 492 is 50% (100 marks), which doesn't make a whole lotta sense as 30+60+100=190, and when was 100 ever half of 190?
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    Is says on the spec we need to know about evidence of size of particles and spacing, is this about the experiment with oil and water?
 
 
 
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