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OCR B (Advancing Physics) G492, 25th May 2012 Afternoon

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Reply 140
What has the highest grade boundary been for an A?
Reply 141
Original post by emma3
What has the highest grade boundary been for an A?


jan 2012, i think, was the highest boundary at 76 for an A. The other boundaries were slightly lower.
Original post by matty b
it's cos it rounds up or down, so the highest/lowest values are +/- 0.005, right?



Original post by Education_1
No you dont half it in this case according to my teacher! yes it would but 0.01 according to him is the uncertainty

EDIT:he is right guys so make sure in the exam you write 0.01A as uncetainty
have a look at
http://www.youtube.com/watch?v=1dTn2pt5PuA (1.14)



Original post by KoalaKim
so what is the uncertainty of the analogue one?? 2??


If you still think the resolution is 0.005 A, consider this example:
say the real value of the current is 0.007 A and it then increases to 0.013 A. Both would read 0.01 on the ammeter, yet the change is 0.006 A, therefore the resolution can't be less than 0.006 A!
Reply 143
Original post by master y
Can anyone tell me why it is particularly important for an ammeter to have 0 resistance for LARGER currents being measured?? (3)


P = I2R, so for high currents (high I) the power dissipated in the ammeter will be large if it has a large resistance (high R), causing the ammeter to overheat.
Reply 144
Original post by When you see it...
If you still think the resolution is 0.005 A, consider this example:
say the real value of the current is 0.007 A and it then increases to 0.013 A. Both would read 0.01 on the ammeter, yet the change is 0.006 A, therefore the resolution can't be less than 0.006 A!


i see ur point, but - say it increases from 0.005A to 0.014A. At both instances, the ammeter would read 0.01A. The variation in results is 0.009. The largest variation from the recorded value, 0.01A, is 0.005A. So, the uncertainty is 0.01 +/- 0.005.

The resolution is 0.01A, as it is the smallest increment measured.
Original post by matty b
i see ur point, but - say it increases from 0.005A to 0.014A. At both instances, the ammeter would read 0.01A. The variation in results is 0.009. The largest variation from the recorded value, 0.01A, is 0.005A. So, the uncertainty is 0.01 +/- 0.005.

The resolution is 0.01A, as it is the smallest increment measured.


http://www.thestudentroom.co.uk/showthread.php?p=37744840&highlight=
Yes resolution is 0.01A i agree but uncertainty is also 0.01
Original post by matty b
i see ur point, but - say it increases from 0.005A to 0.014A. At both instances, the ammeter would read 0.01A. The variation in results is 0.009. The largest variation from the recorded value, 0.01A, is 0.005A. So, the uncertainty is 0.01 +/- 0.005.

The resolution is 0.01A, as it is the smallest increment measured.


Yes I agree that:
Resolution is 0.01 A;
Uncertainty should be 0.005 A.
However, we are supposed to write +/- 0.01 for both for this exam.
I need to set off now - good luck everyone.
Reply 148
Crap, crap crap. Worst exam ever.
What did everyone thinkkkk?


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There were lots of awkward questions but nothing that was particularly awful, really
Reply 151
i thought it was horrible.. and there was barely any mechanics and thats the bit im gd at
Reply 152
it was ok, but I'm not as sure about it as the other exams. How did it compare to physics in action june 2012? I thought that was easier than today's exam.
Anyone fancy discussing any answers they got? I like to compare so I have a rough idea of what I got wrong :tongue:


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Reply 154
Original post by ashton.gibbs
Anyone fancy discussing any answers they got? I like to compare so I have a rough idea of what I got wrong :tongue:


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im happy to... but i cant remember many of them
Thant exam was very hard.... Hopefully very low grade boundaries... Best section was section c, hardest was section B! And what did you have to do for the question about the car going at constant acceleration at 12ms work out x and y?....


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Original post by KoalaKim
im happy to... but i cant remember many of them


I remember the one about the car on the roundabout I got 2.8 and 4.8, but I completely guessed how to do it!! I hated section C :frown:


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Original post by cricket001
Thant exam was very hard.... Hopefully very low grade boundaries... Best section was section c, hardest was section B! And what did you have to do for the question about the car going at constant acceleration at 12ms work out x and y?....


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Ahh I did like section C! I guessed how to do that roundabout one! Found the difference in components before and after turning then divided them by time!


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Reply 158
Original post by ashton.gibbs
I remember the one about the car on the roundabout I got 2.8 and 4.8, but I completely guessed how to do it!! I hated section C :frown:


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I hated section C as well... i definately got 4.8 for the y component and -1.8 or something for the x component
Original post by KoalaKim
I hated section C as well... i definately got 4.8 for the y component and -1.8 or something for the x component


I got 2.8 for x and 4.8 for y. But thinking about it maybe 4.8 shoulda been minus cos it moved down?:/ crap haha


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