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Edexcel Physics Unit 2 "Physics at work" June 2013 Watch

  • View Poll Results: The last question - Does resistance increase or decrease?
    It increases ( using V=IR or some other method)
    70.73%
    It decreases using the 'lattice vibrations' theory
    29.27%

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    (Original post by sarah.102)
    Did you get the marks back for your coursework?
    I either did and forgot or I don't get them back


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    (Original post by vinhvu95)
    I either did and forgot or I don't get them back


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    I didn't, so I doubt you got them as my teacher said that coursework is sent to Edexcel.
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    (Original post by krisshP)
    I didn't, so I doubt you got them as my teacher said that coursework is sent to Edexcel.
    Yep, same case for me
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    Hey, what this everyone put for q6 of the multiple choice? It was Somin about what transition would be caused by the absorption of the lowest frequency of radiation. I put 1 -2 thinking that all electrons are in the ground state, however thinking back on it now I'm not sure if it could have been 4-5 as this gap was the smallest.
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    (Original post by Lennie4Life)
    Hey, what this everyone put for q6 of the multiple choice? It was Somin about what transition would be caused by the absorption of the lowest frequency of radiation. I put 1 -2 thinking that all electrons are in the ground state, however thinking back on it now I'm not sure if it could have been 4-5 as this gap was the smallest.
    The answer for it is 4-5 since it is an absorption and with the lowest frequency,
    when the gap is small there is less energy,and therefore low frequency.
    If it was an emission it would have been 5-4 .
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    btw last question last part many used the equation R=V/I and some talked about filament and vibration and temperature which one is right?
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    hey could i know if anybody is doing physics unit 4 on the 13th ?
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    Guys the grades for each unit are converted in UMS points: 120+120+60= 300. What is usually the grade to get an A out of 300 in the A's??
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    (Original post by Alexsk)
    Guys the grades for each unit are converted in UMS points: 120+120+60= 300. What is usually the grade to get an A out of 300 in the A's??
    to get an A you should get atleast 240.
    to get a B you should get atleast 210.
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    Is this standard?
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    yes it is :P it doesn't change
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    Because to get an A (overall) you should have a total of 480 so half of it is 240,overall B is above 420 so for As level a B is half of it which equals to 210 and for As level a C is above 180 and these are fixxeed values
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    (Original post by krisshP)
    What did you put for 17b, here's the QP
    https://www.dropbox.com/sh/v6ydqbfrg...ZWR-r9ZOSH?lst
    I put something like this, and my answer almost covered the entire page (I got a bit nervous and wrote as much as possible ). Obviously this is in more logical order...

    As long as the voltmeter reading and the ammeter reading gives the true value it'll have no effect in the value of E and r. Now with an ammeter of non-negligible resistance still the current reading and the voltage reading will be accurate for the cell and the additional resistance may be thought to be included in R. But with a voltmeter with low resistance the current/ammeter reading will be inaccurate, as some current flows through the voltmeter
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    does anyone know if and when an unofficial mark scheme is likely to come out?
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    I thought the very last question was referring to the filament lamp in the bulb...I said resistance would decrease because lower current so lower temp. etc...is that wrong? also question about why both current and p.d can be controlled from the mains? why is that? and why doesn't it matter if the ammeter has non-negligible resistance?
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    (Original post by hamzeh h)
    btw last question last part many used the equation R=V/I and some talked about filament and vibration and temperature which one is right?
    I used V=IR, meaning the resistance increases (as it doesn't mention anything about temperature I didn't want to include that in my explanation). Because the resistance increases, as P=VI, P decreases meaning the bulbs don't light because more electrical energy is wasted/dissipated due to the increased resistance. So less goes through the bulbs.

    Don't know if that is right though but I think it makes sense.

    also it doesn't anything about a filament lamp so I didn't put that in my answer because for all we know it could have been fluorescent which isn't affected by temp etc. I think it could have been worded better
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    Well for the very last one I said that as in it is connected in parallel the total voltage would be equal to 230v and so the voltage does not change. As the current is made to decrease then the resistance of each bulb should increase proportionally, as the current through both is the same and the voltage does not change.

    Whether you should mention temperature is bugging me.
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    (Original post by StUdEnTIGCSE)
    Well for the very last one I said that as in it is connected in parallel the total voltage would be equal to 230v and so the voltage does not change. As the current is made to decrease then the resistance of each bulb should increase proportionally, as the current through both is the same and the voltage does not change.

    Whether you should mention temperature is bugging me.
    what did u put for the multiple choice question for the refraction angle?

    angle of incidence was 33 degrees and was the refraction one 21 degrees (or was it the one with 55 degrees) ?
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    (Original post by a10)
    what did u put for the multiple choice question for the refraction angle?

    angle of incidence was 33 degrees and was the refraction one 21 degrees (or was it the one with 55 degrees) ?
    I put 33 and 21....I thought 90-57=33 would give the incident angle...
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    (Original post by Kitnimohabbathai)
    I put 33 and 21....I thought 90-57=33 would give the incident angle...
    I put 33 and 21 as well, but looking at the diagram its confusing it looks like more dense to less dense which would mean its 33 and 55....but from the left that must be air so at the same time I think our answer was correct
 
 
 
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