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    (Original post by Bixel)
    I think the Astronomical Data along with some of the constants are used in A2
    But still, I'm not sure why it's in our booklets...
    I'm pretty sure it's a cost saving strategy as they distribute the same data sheet for AS and A2.
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    Anyone know the circuit symbol for a variable power supply? A lot of the 6 markers want this.
    is it this: http://rpmedia.ask.com/ts?u=/wikiped...symbol.svg.png
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    Does anyone know any definite information on significant figures on the physics exams? I know the norm is do it to the same significant figures as to the highest S.F. as what they've given to you in the question, but mark schemes clearly disagree with this.

    On the questions where it states "Do it to an appropriate amount of S.F." it's always the same S.F. as what they've given you.

    However there is no congruency anywhere else, sometimes they give all their values in 2 S.F. and expect a 3 S.F. answer on the mark scheme. Sometimes they give 3 S.F and expect 2 S.F answer in the mark scheme.

    I'm totally confused. Does anyone know whether you lose marks if you give your answer to 3 S.F. in questions where they don't mention "Do it to an appropriate amount of S.F." but the mark scheme gives the correct answer to 2 S.F.?

    Why can't they just do it like maths and expect 3 S.F. to most of the questions. /rant over and any help appreciated
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    Why are electrons with different kinetic energies emitted when light with photons of the same energy is shone onto a metal? I can't find it in the book but I remember a question on it. Thanks
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    (Original post by SamuelJ)
    Why are electrons with different kinetic energies emitted when light with photons of the same energy is shone onto a metal? I can't find it in the book but I remember a question on it. Thanks
    Because some the electron will be deeper into the metal and require more energy to release them, therefore they will have less Kinetic Energy compared to those that were released from atoms on the surface of the metal for example
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    This may seem silly but can anyone give me a definition to learn for emf?
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    (Original post by hassantahir)
    Anyone know the circuit symbol for a variable power supply? A lot of the 6 markers want this.
    is it this: http://rpmedia.ask.com/ts?u=/wikiped...symbol.svg.png
    Yeah it's basically that As long as you have the symbol for the source of power, i.e. the cell, and the arrow to represent that it varies, you couldn't really be wrong! If you have to include it in a diagram, there's nothing wrong with labelling it as a variable power supply, if anything it's better!
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    (Original post by BajoLily)
    This may seem silly but can anyone give me a definition to learn for emf?
    It's the work done per coulomb charge when there's no resistance including internal resistance.

    The voltage equals the EMF when current equals zero

    V= EMF - Ir

    I think that's about all you need to know
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    (Original post by dada55)
    Does anyone know any definite information on significant figures on the physics exams? I know the norm is do it to the same significant figures as to the highest S.F. as what they've given to you in the question, but mark schemes clearly disagree with this.

    On the questions where it states "Do it to an appropriate amount of S.F." it's always the same S.F. as what they've given you.

    However there is no congruency anywhere else, sometimes they give all their values in 2 S.F. and expect a 3 S.F. answer on the mark scheme. Sometimes they give 3 S.F and expect 2 S.F answer in the mark scheme.

    I'm totally confused. Does anyone know whether you lose marks if you give your answer to 3 S.F. in questions where they don't mention "Do it to an appropriate amount of S.F." but the mark scheme gives the correct answer to 2 S.F.?

    Why can't they just do it like maths and expect 3 S.F. to most of the questions. /rant over and any help appreciated
    As I said a few pages back, you will only lose significant figures if the question explicitly state that you need to give your answer to an appropriate number of sig figs. So no, you don't lose marks on those.
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    (Original post by hassantahir)
    Anyone know the circuit symbol for a variable power supply? A lot of the 6 markers want this.
    is it this: http://rpmedia.ask.com/ts?u=/wikiped...symbol.svg.png
    I don't think the 6 marks ask for a variable power supply, I think they ask for a way to vary the pd eg variable resistor. Which 6 markers in particular said this? (I might be wrong - need to check)
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    Can anyone help with question 6b jan 2013 ?????

    PLEASE!!!
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    (Original post by Bixel)
    Yeah it's basically that As long as you have the symbol for the source of power, i.e. the cell, and the arrow to represent that it varies, you couldn't really be wrong! If you have to include it in a diagram, there's nothing wrong with labelling it as a variable power supply, if anything it's better!
    in that case what is the symbol for a power supply? the two dots with a gap?
    And so to show it variable just an arrow though it diagonally?
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    (Original post by posthumus)
    Because some the electron will be deeper into the metal and require more energy to release them, therefore they will have less Kinetic Energy compared to those that were released from atoms on the surface of the metal for example
    Thank you!
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    With potential dividers, how are we meant to know which resistors are R1 and R2?


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    (Original post by Jimmy20002012)
    With potential dividers, how are we meant to know which resistors are R1 and R2?


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    The notational doesn't really matter so much but R2 is typically the with Vout across it... the one you are getting the potential from basically
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    (Original post by posthumus)
    It's the work done per coulomb charge when there's no resistance including internal resistance.

    The voltage equals the EMF when current equals zero

    V= EMF - Ir

    I think that's about all you need to know
    Thanks so much!
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    Does anyone have a list of all the important formulas we'll need to use?

    Also, what do you lot think the 6 marker will be on? I'm predicting something on oscilloscopes to be honest.
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    (Original post by PickwickianGeek)
    Does anyone have a list of all the important formulas we'll need to use?

    Also, what do you lot think the 6 marker will be on? I'm predicting something on oscilloscopes to be honest.
    Unlikely oscilloscopes will come as it came in June 2012, I think it will be so etching about the photoelectric effect as it hasn't come since 2010


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    (Original post by posthumus)
    The notational doesn't really matter so much but R2 is typically the with Vout across it... the one you are getting the potential from basically
    The normal potential divider equation is:

    Voltage output= Voltage in X R2/Total resistance in branch

    So in the January 2013 paper when you are meant to find the voltage output of D-F I thought it would be 6 x 5/15= 2V, but it is the other way round, could you explain?


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    (Original post by Jimmy20002012)
    Unlikely oscilloscopes will come as it came in June 2012, I think it will be so etching about the photoelectric effect as it hasn't come since 2010


    Posted from TSR Mobile
    What kind of question could they ask us on the Photoelectric effect for 6 marks, that hasn't already been done before then?
 
 
 
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