Join TSR now and get all your revision questions answeredSign up now

OCR PHYSICS B G494~ 11th June 2015 AM ~ A2 Physics Watch

    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by mariamaisabelle)
    I just wrote that it does work with the equation because they were all like 351, 352, 353 so they were all 350 to (2.s.f.) and the differences are just due to experiments always have error! or something like that anyway
    but they probably accept it if you say it doesnt work with the equation as long as you justified why!!

    you rounded to 2sf, but the data was to 3sf so you're being inaccurate here
    I';m pretty sure it wasn't constant
    I remember a question in another paper when they were close and it rejected them
    Offline

    1
    ReputationRep:
    (Original post by malachirp)
    I wouldn't give up hope of getting all those marks, often the markscheme accepts both as long as you explain why you came to your conclusion and it is valid. That being said i also said the relationship was true
    Good point, I agree that either conclusion should be accepted if you have decent reasoning, and if the mark scheme says that for similar questions then can't argue with that.

    Posted from TSR Mobile
    Offline

    3
    ReputationRep:
    (Original post by Mutleybm1996)
    Did you get the values as constant relationship or not?

    I know I made some mistakes, but I don't think it's enough to cost me an A
    Well, I hope not any way!
    Yeah I said the relationship was consistent to a certain degree of accuracy.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Iridann)
    Yeah I said the relationship was consistent to a certain degree of accuracy.
    will either conclusion be accepted?
    depends on whether we say they're significantly different or not
    Offline

    3
    ReputationRep:
    (Original post by rapunzelsa)
    I said they were different, i tested it out with much higher values of T and lower values of p that still fitted with the pattern in the table, and it was definitely not constant, but i don't know what they wanted :-(
    I said they were all within +- 1 so it was true
    Offline

    3
    ReputationRep:
    (Original post by MasterOfTheSwag)
    I got numbers around the value 352 for each one so I said that it was constant, as the +-1 difference was negligible
    Me too!
    Offline

    3
    ReputationRep:
    (Original post by Lewis7253)
    I said the same . Didnt think the paper was that bad. Some of the questions were tricky and took a while. Did anyone else get something like 1.22x10^-10 for G. And 2.7x10^23 collisions per second
    Yes for both
    Offline

    12
    ReputationRep:
    (Original post by Mutleybm1996)
    you rounded to 2sf, but the data was to 3sf so you're being inaccurate here
    I';m pretty sure it wasn't constant
    I remember a question in another paper when they were close and it rejected them
    I'm sure you're right, but from what I remember of primarily the legacy papers it stated that it if the relationship held to the number of significant figures within the tolerance of the data, then you could make the assertion regarding the relationship for the purposes of A Level.

    Normally, the marking points are:

    -valid test.. [1]
    -..correctly applied on two or more data sets [1]
    -valid conclusion [1]

    So worst case, and I may be wrong, you should only lose one mark for an incorrect conclusion.
    Offline

    3
    ReputationRep:
    (Original post by Mutleybm1996)
    Oops I did 10-1
    The rest was right though
    How many marks lost?


    Posted from TSR Mobile
    Did the correct method but did 1/10 not 10/1 so got 4.80*10^-20 :/ how many marks left if my method was exactly correct except for that one mistake? :/
    Offline

    1
    ReputationRep:
    (Original post by Rhetorical Hips)
    Damn I screwed up the pV=constant one. I worked it out then proceeded to divide p by V instead of multiplying! Asides from that, what I wrote what correct - the 'equation' they gave you was not valid because the values calculated were not constant (for me at least).

    How many marks was that question? 3/4? Hopefully I'll only lose 1 or 2 marks for that

    Nice markscheme anyway 😊


    Posted from TSR Mobile
    That question was only 2 marks
    Offline

    2
    ReputationRep:
    (Original post by Greating)
    This is what a friend and I think are acceptable answers, though there is some uncertainty in some of the longer explanation questions.

    Our answers are attached.
    Where was the radioactivity question????

    Help! Did I miss a page???
    Offline

    1
    ReputationRep:
    (Original post by Greating)
    This is what a friend and I think are acceptable answers, though there is some uncertainty in some of the longer explanation questions.

    Our answers are attached.
    For question 6, the gravitational equipotentials, I put C, the straight line straight through the middle of the two planets. My thinking behind that is that along that line, the gravitational forces of the two planets are equal and opposite, so the force on that line is zero.
    Offline

    1
    ReputationRep:
    (Original post by mauriceyap)
    For question 6, the gravitational equipotentials, I put C, the straight line straight through the middle of the two planets. My thinking behind that is that along that line, the gravitational forces of the two planets are equal and opposite, so the force on that line is zero.
    I put C, it would be correct if the question was asking where the gravitational forces from both the planets were equal but I think it might have been asking where the gravity felt by the object was equal
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by Mathangi)
    I put C, it would be correct if the question was asking where the gravitational forces from both the planets were equal but I think it might have been asking where the gravity felt by the object was equal
    Pretty sure it's B


    Posted from TSR Mobile
    Offline

    14
    ReputationRep:
    (Original post by mauriceyap)
    For question 6, the gravitational equipotentials, I put C, the straight line straight through the middle of the two planets. My thinking behind that is that along that line, the gravitational forces of the two planets are equal and opposite, so the force on that line is zero.
    C would be where the gravitational force exerted by the two planets cancel out.

    I actually couldn't work it out myself, it was a toss up between B and C, but the fact that equipotentials are usually spherical meant that I guessed B.
    Offline

    1
    ReputationRep:
    (Original post by Mathangi)
    I put C, it would be correct if the question was asking where the gravitational forces from both the planets were equal but I think it might have been asking where the gravity felt by the object was equal
    Yes, that is true in that it is a line of zero resultant force, but there is still gravitational potential from both planets as you move outwards along that line, so the potential changes.

    Since equipotentials are lines when the potential is the same, the vertical line through is not an equipotential, but it is a line of zero force.
    Offline

    3
    Thoughts on boundaries?
    Offline

    0
    ReputationRep:
    I know the data is to 3sf but if they're all with like +/-2 of each other then I would think that means that its pretty much constant and obviously data from an experiment will always have error so I just wrote that
    Offline

    3
    ReputationRep:
    (Original post by Mathangi)
    I put C, it would be correct if the question was asking where the gravitational forces from both the planets were equal but I think it might have been asking where the gravity felt by the object was equal
    (Original post by mauriceyap)
    For question 6, the gravitational equipotentials, I put C, the straight line straight through the middle of the two planets. My thinking behind that is that along that line, the gravitational forces of the two planets are equal and opposite, so the force on that line is zero.
    It was V grav, not F
    Offline

    2
    ReputationRep:
    So is there an unofficial mark scheme about? Feel like I got 51 marks. Not really happy about that.
 
 
 
Poll
Which web browser do you use?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.