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    (Original post by usycool1)
    Ah well, just one mark I threw away a mark on the Oscilloscope question where they asked us to draw the d.c. one...I put a straight line on the peak voltage instead of the rms voltage for some reason :mad: Ah well, the rest was OKish
    Damn I did that too!!
    ahhhh throwing away marks here
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    (Original post by posthumus)
    How many marks was the rms plotting question ? Didn't even do it !

    What'd you do for the first question

    & Also what'd you get for the final questions

    Thanks !
    2, I think, not many.

    Can't remember, except I know I got 30000 ohms on the last one or something
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    Did anyone include the electron's mass in the specific charge?


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    Damn I divided 20 by 8 instead of 10 because they said vertical, I interpreted that wrong, anyone know how many marks I would lose?


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    Yeah I got the same values. Except for the oscilloscope thing you had to write how you would divide the scale. That's why it gave how many divisions were on the oscilloscope.


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    (Original post by FrankB3)
    Did anyone include the electron's mass in the specific charge?


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    It only makes a difference at the 4th sig fig, so it doesn't matter, but I did include it anyway...


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    I got 7XXXX ohms for the last question. No idea how you got 30k
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    (Original post by Tuya)
    Damn I divided 20 by 8 instead of 10 because they said vertical, I interpreted that wrong, anyone know how many marks I would lose?


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    I did exactly that at first! Very mean way of wording it! If a lot of people did that they may condone the slip up.
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    Anyone have access to the paper?


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    you know on the specific charge one on question one, I completely forgot to add the mass of the electrons, kicking myself for making such a stupid mistake!


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    (Original post by GeneralOJB)
    Well that was one piss easy exam! Finished with like 30 minutes to spare. Full marks here I come.
    What did you get for the last question?

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    (Original post by Mr. T. Face)
    Um, no, (6/10000+x)*5000=0.75, so x = 30000 Ohms
    I got 30,000 too.

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    (Original post by GeneralOJB)
    I did exactly that at first! Very mean way of wording it! If a lot of people did that they may condone the slip up.
    Do you reckon I would lose all 3 marks if I was in the minority though? And any idea for cap boundary ?


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    (Original post by hannahclaire)
    you know on the specific charge one on question one, I completely forgot to add the mass of the electrons, kicking myself for making such a stupid mistake!


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    I don't think it matters, I think you end up with the same value....
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    (Original post by hannahclaire)
    you know on the specific charge one on question one, I completely forgot to add the mass of the electrons, kicking myself for making such a stupid mistake!


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    It only makes a difference at the 4th sig fig, so it doesn't matter


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    (Original post by Ryejd)
    I got 7XXXX ohms for the last question. No idea how you got 30k
    For 0.75 to pass through the 5k resistor, the current must be 0.75/5000 = 1.5x10-4 A. This means the overall resistance must be 6/1.5x10^-4 = 40000 ohms. You already have 5000 ohms on the resistor R and 5000 ohms on the LDR which you were given, so the variable resistor must be 40000-5000-5000 = 30000 ohms.
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    (Original post by hannahclaire)
    you know on the specific charge one on question one, I completely forgot to add the mass of the electrons, kicking myself for making such a stupid mistake!


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    The mass of electrons are so small it doesn't make a difference if you included it or not

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    i think i got all the marks other than maybe losing a couple of marks for wording on the wordy questions
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    At first I didn't realise that the time axis was in milliseconds. Lucky I looked over it when I was checkig


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    For the oscilloscope question, I did 20v per division not 16v. Will they both be accepted, so like in the mark scheme, will it say 'accept any sensible value?' I'm guessing the main thing about the question was that you had to write that the time base had to be set at 2ms per division so that the two cycles can be seen. Hmm...
 
 
 
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