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OCR Physics A G485 - Frontiers of Physics - 18th June 2015

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Original post by bmwdestroyer
Any advice on cramming for this exam this evening, barely done any revision at all so far, only been over some universe stuff and capacitors


Go through all the papers online and copy out the mark schemes of the wordy questions as bullet points on a notepad. It's a good way of memorising exactly what phrases they're looking for.
Original post by Zenarthra
Any others?


Well I would say dont revise everything that came up last year but MRI was in June 2011 June 2012 and Jan 2012 and was all worth about a 10% of the marks
Can anyone explain question 6bii on the June 2014 paper.
Also 7bi on the same question, I get that it's the I=Ioe^-ux equation but why do I just use the e^=ux and ignore the rest? This is the same with all equations with e in, when can I ignore the first two terms?
Guys, collective predictions for big markers on all 4 sections? (Electricity, Nuclear, Medical and Universe)??? This is my last exam, need at least a solid C to get a B at A-level for my offer!!!).
Original post by FeelsToWaltz
It doesn't matter as long as they're the same unit, as the units cancel out in the calculation. So m and cm wouldn't work but cm and cm, or m and m would work!


thankyou :biggrin:
Original post by MrChemKid
in the equation I=Ie^mu X ( for x rays)

does the mu and x have to be in cm or m?


whatever is given in question, doesnt matter
Original post by I Persia I
Guys, collective predictions for big markers on all 4 sections? (Electricity, Nuclear, Medical and Universe)??? This is my last exam, need at least a solid C to get a B at A-level for my offer!!!).


Evolution of the universe, Gamma Camera, MRI/CAT scans, circular motion with magnetic field and alpha scattering experiment.
Judging by this year's F325, F322 and G482 papers I don't think this exam will be too tough. It seems OCR are just getting tough on the first modules of each course. Only thing I'm worried about is low grade boundaries. Last year was 69 for an A which is the lowest it's been since June 2011.

June 2010: 66
Jan 2011: 65
June 2011: 64
Jan 2012: 76
June 2012: 77
Jan 2013: 81
June 2013: 73
June 2014: 69
(edited 8 years ago)
Original post by pje1000
i dont understand magnetix flux/magnetic flux density/magnetic flux linkage, could somebody explain like...all of it please. And the common exam questions that come up on it as i think its my only weak area, thanks!

Magnetic flux density etc:

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Here's a question from June 2013 which is fairly typical
edexcel sending.jpg
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edit: sorry about all of the photos being sideways! they're the right way up on my laptop but apparently tsr is having none of it
(edited 8 years ago)
Original post by bmwdestroyer
Any advice on cramming for this exam this evening, barely done any revision at all so far, only been over some universe stuff and capacitors


Medical, learn all the principles then pray
Original post by physicsandbeer
Judging by this year's F325, F322 and G482 papers I don't think this exam will be too tough. It seems OCR are just getting tough on the first modules of each course. Only thing I'm worried about is low grade boundaries. Last year was 69 for an A which is the lowest it's been since June 2011.

June 2010: 66
Jan 2011: 65
June 2011: 64
Jan 2012: 76
June 2012: 77
Jan 2013: 81
June 2013: 73
June 2013: 69

Why is low worrying?
Reply 1391
Original post by physicsandbeer
Judging by this year's F325, F322 and G482 papers I don't think this exam will be too tough. It seems OCR are just getting tough on the first modules of each course. Only thing I'm worried about is low grade boundaries. Last year was 69 for an A which is the lowest it's been since June 2011.

June 2010: 66
Jan 2011: 65
June 2011: 64
Jan 2012: 76
June 2012: 77
Jan 2013: 81
June 2013: 73
June 2013: 69


If it is below 75 for an A i'll be very happy. I just need a few marks into an A for an A overall and i'm finally done with physics.
Original post by physicsandbeer
Judging by this year's F325, F322 and G482 papers I don't think this exam will be too tough. It seems OCR are just getting tough on the first modules of each course. Only thing I'm worried about is low grade boundaries. Last year was 69 for an A which is the lowest it's been since June 2011.

June 2010: 66
Jan 2011: 65
June 2011: 64
Jan 2012: 76
June 2012: 77
Jan 2013: 81
June 2013: 73
June 2013: 69


June 10 - June 11 had 15 minutes less so effectively disregard them.
Original post by chem@uni
Why is low worrying?

Because it might bounce back up this year. I find I always do worse on the higher grade boundary "easier" papers because it's easy to lose enough stupid marks by mistake to push you over the boundary.
Original post by Elcor
June 10 - June 11 had 15 minutes less so effectively disregard them.


I personally don't think the extra 15 minutes makes that much difference.
Is the attenuation coefficient in cms? so for 5cm x=5? and if its 3mm of depth does x=0.3, because I did a question where I though it was measured in metres so when a depth was like 3mm I put x as 3x10^3 put I still got the answer right.
Challenging paper with ~ 70 for an A, heavy on calculations and medical please :biggrin:
Original post by physicsandbeer
I personally don't think the extra 15 minutes makes that much difference.


It's more of a 'finishing the exam' thing than checking over probably. Also you'd be daft to not see the trend in the grade boundaries. You're probably quicker than the average student.
Urgent -----------------------------------------
Please help with question 6bii on the june 2014 paper, I don't get why I only use the e^-ux and not use the I=I0 part at the start. Really need help on this as going to get an early night soon
Original post by leroythelost
Is the attenuation coefficient in cms? so for 5cm x=5? and if its 3mm of depth does x=0.3, because I did a question where I though it was measured in metres so when a depth was like 3mm I put x as 3x10^3 put I still got the answer right.


If you're using the attenuation coefficient in the exponential relationship june13.4bii.pngthe units cancel out so as long as the units of x and mu are the same it doesn't matter (as you're multiplying m by m^-1 or cm by cm^-1)

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