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    I spelt 'laser' like... 'lasor'. Do you think they'll give me the mark
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    (Original post by Bulbasaur10)
    I got 1600m/s. I don't know if it is actually right, but I did something like this:

    The ultrasound travelled 4cm twice over as it went from the skin to the baby and back to the skin/transducer, which is 8cm = 0.08m.

    The time taken for this was 80 microseconds - 30 microseconds, which is 50 microseconds.

    Speed is distance/time = 0.08m/50x10^-6s = 1600m/s

    Is this right though???
    For that question I did the wrong working out, I had the right idea just typed the numbers in wrong I think and I got 1600 m/s. Will I get all 3 marks?
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    Which exam did you like more guys, P2 or P3?
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    (Original post by MaxHSloan)
    For that question I did the wrong working out, I had the right idea just typed the numbers in wrong I think and I got 1600 m/s. Will I get all 3 marks?
    You might get 3 marks, but I guess it depends in the examiner. They might not even notice that your working out is wrong as long as you wrote the correct formula down, so it is very possible Also, there are other ways to work it out so you might just have done another method!
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    (Original post by Bulbasaur10)
    You might get 3 marks, but I guess it depends in the examiner. They might not even notice that your working out is wrong as long as you wrote the correct formula down, so it is very possible Also, there are other ways to work it out so you might just have done another method!
    I had the correct formula and everything, just put the numbers in the calculator wrong. Did 0.8/50x10^-5. That isn't correct calculation but gives right answer
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    (Original post by MaxHSloan)
    I had the correct formula and everything, just put the numbers in the calculator wrong. Did 0.8/50x10^-5. That isn't correct calculation but gives right answer
    Oh ok, but they are equivalent so maybe it won't matter! Honestly if you gave the correct formula and converted the units correctly it will be fine.
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    (Original post by Bulbasaur10)
    Oh ok, but they are equivalent so maybe it won't matter! Honestly if you gave the correct formula and converted the units correctly it will be fine.
    Ok cheers
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    (Original post by brotherteresa256)
    Right, that exam was awfully hard... Let's make a mark scheme guys. Please put in any questions or answers you can, preferably with question number if you can remember it. I'll try to keep updating it as best I can, but i'm only human

    ALSO, THIS MARK SCHEME IS VERY INCOMPLETE, SO DON'T EXPECT IT TO BE 100% CORRECT


    1.
    a) Why was electromagnet better for sorting rubbish? (1 mark)
    Because it can be switched on and of/activated and deactivated OR it is more powerful than a normal magnet
    b) How can the students use this equipment to create an electromagnet, and test it - and vary its strength? (6 marks)
    Wrap Insulated wire around nail. Suspend in the wooden clamp. Attach to power supply with connectors. put paperclips under and increase power until paperclip is attracted OR set to certain power and lower until paperclip is attracted. Then repeat with different height/power.



    Unknown Question numbers/answers:

    2 - Radiation/ultrasound Questions
    Calculation: 0.08m or 0.04m divided by 110x10^-6 or 50x10^-6, We're not sure yet (but I think the answer is 400 m/s) (3 mark)
    Why is X-rays not used with unborn babies?: X-ray causes ionisation which are damaging to the foetus' cells, causing them to become mutant and divide uncontrollably. This leads to cancer. (3 marks)
    How does an X-ray work question: X-rays emitted toward a photographic CCD. Hard tissue like bone absorbs the rays, making them white on the image, but softer tissue allows them to pass through (3 mark)
    Question on wavelength: Shorter (1 mark)

    3 - Stability Questions
    What is meant by the 'centre of mass'?: the point where the mass appears to be concentrated (1 mark)
    Why is tower B more unstable than A?: narrower base, higher centre of mass (2 mark)
    Why doesn't this tower fall over?: The line of action of the weight lies within the base so there is no resultant moment causing it to topple (2 mark)

    4 - Foot peddle and drums/Moments questions
    What is meant by moment of the force: A DICTIONARY DEFINITION: "A measure of the turning effect produced by a force about an axis.The magnitude of the moment is the product of the force and the perpendicular distance from the axis to the line of action of the force" (1 mark)
    1.5 N force from toe. 0.20m from pivot to the chain. 0.12m from pivot to toe: 0.9N??? (3 marks)
    Graph showing different lengths of drum hinges compared to volume of sound produces at different forces (3, 6, 9 newtons) (2 mark)

    5 - Eye correction/lenses/Ray trace diagram questions
    Critical angle (2 significant figures): 1/1.5 = 0.6666.. sin^-1(0.6666..) = 42 degrees (3 mark)
    (image was formed behind object, magnified, and was virtual because the lines on the other side of the lens did not converge)??? (3 mark)
    Reason for long longness: Lens in eye too weak OR eyeball too short (1 mark)
    Source of energy for cutting cornea: LASER (1 mark)
    (Not too sure, but there was an M/N object question) (3 mark)
    C/B lens question: draw the lens fatter??? (1 mark)


    Grade boundaries are looking low too. from a purely personal viewpoint (don't take these 100% seriously) these are what i think the boundaries will be:

    A* - 40
    A - 34
    B - 28
    C - 23
    D - 17
    E - 12


    (P.S. Below are some mark schemes for the P2 exam you wonderful physicists might want)
    http://www.thestudentroom.co.uk/show....php?t=4171131
    http://www.thestudentroom.co.uk/show....php?t=4171228
    http://www.thestudentroom.co.uk/show....php?t=4171902 --- This one is probably the best, well done to lily628 for making it
    Hi, thanks for putting it together. For Question 2, I believe the speed of the ultrasound was 1600m/s. You divide 50x10^-6 by 2, which is 25x10^-6, then divide 0.04 by that, getting you 1600, so 1600m/s. Also, my teacher said the average speed of ultrasound in soft tissues is approximately 1,540m/s, so the answer 1600m/s should be right.
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    (Original post by MaxHSloan)
    For that question I did the wrong working out, I had the right idea just typed the numbers in wrong I think and I got 1600 m/s. Will I get all 3 marks?
    Yep. In Science exams, you can scribble down any nonsense in the workings out and still get full marks if you write the correct answer in the final answer space.
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    Don't worry the grade boundaries are gonna be super low! P3 2015 was so much easier and that was around 43 ish for an A*. So this year for both physics papers will be like max 40 x
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    [QUOTE=Akila1;65883066]Isnt the moments question 0.5625 Nm?
    1.5 x 1.2 = 1.8
    1.2 + 2.0 = 3.2 (distance of the chain from the pivot)
    1.8/3.2 = 0.5625[/QUO
    Yeah dos I got that to... I remember
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    [QUOTE=Omz123;65896008]
    (Original post by Akila1)
    Isnt the moments question 0.5625 Nm?
    1.5 x 1.2 = 1.8
    1.2 + 2.0 = 3.2 (distance of the chain from the pivot)
    1.8/3.2 = 0.5625[/QUO
    Yeah dos I got that to... I remember
    I did something similar, but why did you have to add 1.2 and 2? Please help. I thought it already told you the distance from the chain to the pivot...
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    [QUOTE=Bulbasaur10;65896348]
    (Original post by Omz123)

    I did something similar, but why did you have to add 1.2 and 2? Please help. I thought it already told you the distance from the chain to the pivot...
    No it was split up into 2 sections...so I thought to add em up...common sense really but I don't know if it's right
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    [QUOTE=Omz123;65896472]
    (Original post by Bulbasaur10)

    No it was split up into 2 sections...so I thought to add em up...common sense really but I don't know if it's right
    Oh, was it really? I must have missed that..... I thought it just said the distance from the chain to the pivot of the pedal was '....', and the distance from the foot's centre of mass to the same pivot was '.....'. Was there a second pivot, or did it give the distance from the foot's centre of mass to the chain? Can anyone remember the exact question?
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    (Original post by mediaya)
    Whaaaaaaatt!!! 😠😠i am just sooo stupid i forgot to do inverse sin 😢😢 love maths sooooo much but with physics...... I forget that there is maths so i leave my maths brain at home😒
    Aww! I did the same thing as you, forgetting to use the sine^-1... So my final answer was 0.67 degrees. Somehow I read that as 67 degrees, so I left that as it was xD
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    (Original post by Bulbasaur10)
    I got 1600m/s. I don't know if it is actually right, but I did something like this:

    The ultrasound travelled 4cm twice over as it went from the skin to the baby and back to the skin/transducer, which is 8cm = 0.08m.

    The time taken for this was 80 microseconds - 30 microseconds, which is 50 microseconds.

    Speed is distance/time = 0.08m/50x10^-6s = 1600m/s

    Is this right though???
    That's exactly what I put! And I spoke to my physics teacher about it afterwards and he said he thinks I got it right
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    (Original post by melhoare)
    That's exactly what I put! And I spoke to my physics teacher about it afterwards and he said he thinks I got it right
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    For the refractive index question I worked out 1/1.5 to get 0.6 recurring, however then i did the sin-1(0.6) and not 0.6 recurring - how may marks?
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    (Original post by brotherteresa256)
    Right, that exam was awfully hard... Let's make a mark scheme guys. Please put in any questions or answers you can, preferably with question number if you can remember it. I'll try to keep updating it as best I can, but i'm only human

    ALSO, THIS MARK SCHEME IS VERY INCOMPLETE AND NOT ALL THE ANSWERS ARE HERE, SO DON'T EXPECT IT TO BE 100% CORRECT


    1.
    a) Why was electromagnet better for sorting rubbish? (1 mark)
    Because it can be switched on and of/activated and deactivated OR it is more powerful than a normal magnet
    b) How can the students use this equipment to create an electromagnet, and test it - and vary its strength? (6 marks)
    Wrap Insulated wire around nail. Suspend in the wooden clamp. Attach to power supply with connectors. put paperclips under and increase power until paperclip is attracted OR set to certain power and lower until paperclip is attracted. Then repeat with different height/power.



    Unknown Question numbers/answers:

    2 - Radiation/ultrasound Questions
    Calculation: 0.08m or 0.04m divided by 110x10^-6 or 50x10^-6, We're not sure yet (but I think the answer is 1600 m/s) (3 mark)
    Why is X-rays not used with unborn babies?: X-ray causes ionisation which are damaging to the foetus' cells, causing them to become mutant and divide uncontrollably. This leads to cancer. (3 marks)
    How does an X-ray work question: X-rays emitted toward a photographic CCD. Hard tissue like bone absorbs the rays, making them white on the image, but softer tissue allows them to pass through (3 mark)
    Question on wavelength: Shorter (1 mark)

    3 - Stability Questions
    What is meant by the 'centre of mass'?: the point where the mass appears to be concentrated (1 mark)
    Why is tower B more unstable than A?: narrower base, higher centre of mass (2 mark)
    Why doesn't this tower fall over?: The line of action of the weight lies within the base so there is no resultant moment causing it to topple (2 mark)

    4 - Foot peddle and drums/Moments questions
    What is meant by moment of the force: A DICTIONARY DEFINITION: "A measure of the turning effect produced by a force about an axis.The magnitude of the moment is the product of the force and the perpendicular distance from the axis to the line of action of the force" (1 mark)
    1.5 N force from toe. 0.20m from pivot to the chain. 0.12m from pivot to toe: 0.9N??? (3 marks)
    Graph showing different lengths of drum hinges compared to volume of sound produces at different forces (3, 6, 9 newtons) (2 mark)

    5 - Eye correction/lenses/Ray trace diagram questions
    Critical angle (2 significant figures): 1/1.5 = 0.6666.. sin^-1(0.6666..) = 42 degrees (3 mark)
    (image was formed behind object, magnified, and was virtual because the lines on the other side of the lens did not converge)??? (3 mark)
    Reason for long longness: Lens in eye too weak OR eyeball too short (1 mark)
    Source of energy for cutting cornea: LASER (1 mark)
    (Not too sure, but there was an M/N object question) (3 mark)
    C/B lens question: draw the lens fatter??? (1 mark)


    Grade boundaries are looking low too. from a purely personal viewpoint (don't take these 100% seriously) these are what i think the boundaries will be:

    A* - 40
    A - 34
    B - 28
    C - 23
    D - 17
    E - 12


    (P.S. Below are some mark schemes for the P2 exam you wonderful physicists might want)
    http://www.thestudentroom.co.uk/show....php?t=4171131
    http://www.thestudentroom.co.uk/show....php?t=4171228
    http://www.thestudentroom.co.uk/show....php?t=4171902 --- This one is probably the best, well done to lily628 for making it
    Q5. Describe how the image changes if the bulb was moved from N to M.

    The image would become smaller (1), it would become real (1) and it would become inverted. (1)
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    I cant remember seeing a question on asking to describe the bulb and drawing the lens fatter. I did p3 ?
 
 
 
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