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OCR Physics A Breadth of Physics (24th May 2016) Discussion

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Original post by mxixbl
I got 7520 for the density because I rounded early, will that drop me marks?


I kept my values in the calculator and after rounding to the correct number of sig figs got 7520, so I wouldn't worry.
how many marks for very last question? and how many marks do you reckon 90 ums?
Original post by Suat
I did

was this the thin to thick ratio?
Reply 463
Hi in regards to this post i'd just like to let you know that you said "multiple choice questions thanks to abeh" but in fact me Daniaal and my friend (Yiannis) are the ones who found that book and took a long time to convert it into a pdf hence it has a watermark on the bottom with our names on every single page of the document and the google drive link you have posted is from Yiannis's google drve and he originally shared it on the a level physics online youtube channels comment section for the mcq video.

Some people on other threads have posted it too but I just wanted to make it clear that we are the ones who spent a long time finding that ebook and then converting it.

I also have the chemistry version of the same book if anyone's interested.

Many Thanks.


Original post by Infinity999
I haven't been on this site for a long time, but I was surprised not to see a Breadth of Physics discussion for the OCR A exam. So I thought I'd make one.

Here are some resources I looked at in the past few months:

. http://twyfordphysics.blogspot.co.uk/ ( this has most of the waves notes and electricity notes for the new spec.)
. PhysicsandMathsTutor.com (most people use this and if you haven't already please do!)
. http://www.thestudentroom.co.uk/showthread.php?t=3517229 (OCR A Physics A* resources by @ForgottenApple )
. http://www.saintolaves.net/uploads/ckeditor/attachments/999/AS_Revision_Checklist.pdf (thanks to @Marxist)
. http://www.thestudentroom.co.uk/showthread.php?t=4100393 (Questions on Experiments thanks to @voltz)
. https://drive.google.com/file/d/0Byy0joJp_zfMSUJmTjVpcFpYME0/view?pref=2&pli=1 (Multiple Choice questions thanks to @Abeh)
. https://drive.google.com/open?id=0B2jqkYvna6gNODhpYzNMZEVGNVk (Teachers Pack OCR)
Reply 464
Original post by alex19678
Same :smile:


What was the answer though???
mark scheme anyone
1. Was the thin/thick ratio 0.125? and was the current anticlockwise being more at X?
2Was ball B moving downwards and A upwards?
3. What were we meant to write for the force on asteroid description? how many marks was it?
4. INn the emf question I got the ciruit and readings but I didn't write abot the graph however I did write that the y- intercept is the emf...how many marks out of what it was out of could I get?
5. In the LED question what did we have to write to describe the voltage?
6. In the way to measure the wavelength it would be just measuring XY and timesing it by 4, we didn't have to say about an instrument did we?
7. What was the very last question and how many marks was it?
Anyone have any idea what the question about the EPE of the springs was.
Original post by Parhomus
Same, just not sure about the one with wave speed, I got 60+-0.3, I think the uncertainty is probably wrong.


I got the same
Reply 469
[QUOTE=Parhomus;65124177]Anyone have any idea what the question about the EPE of the springs was.

I said 16 but im not even sure if its correct
Reply 470
Original post by chemari1
1. Was the thin/thick ratio 0.125? and was the current anticlockwise being more at X?
2Was ball B moving downwards and A upwards?
3. What were we meant to write for the force on asteroid description? how many marks was it?
4. INn the emf question I got the ciruit and readings but I didn't write abot the graph however I did write that the y- intercept is the emf...how many marks out of what it was out of could I get?
5. In the LED question what did we have to write to describe the voltage?
6. In the way to measure the wavelength it would be just measuring XY and timesing it by 4, we didn't have to say about an instrument did we?
7. What was the very last question and how many marks was it?


1) Can't really remember.
2) Can't really remember, but imagine the wave was shifted to the right, then you draw the arrow from A and B to the next wave, and you can find if it goes up or down.
3) Force on asteroid was 2 marks, you were supposed to talk about the reaction force it experiences from Newton's 3rd law when it pushes against the comet, and also how the comet pushes on the asteroid with it's own force.
4) Will probably drop you 2 marks since the point of the question was to find internal resistance, you may only drop 1 if they emphasize repeating the experiment, if you wrote about that.
5) LED question, the voltage was insufficient to light up the LED, and the diode was pointing the wrong way. To make the circuit work, reverse polarity on the battery or switch direction of diode, then say for the LED to light up you need a sufficient voltage above the threshold. (Read from graph)
6) XY is wavelength/2, you have to multiply by 2, not 4. Probably needed to mention tape measure or something.
7) Last question was about how resistance changes as voltage changes in a diode VI characteristic. The very last part was the calculate number of photons emitted from LED per second or something. Total 8 marks or so.
Here are some answers I remember.

For the adding a vecotor and scalar quantity, I would write with adding velocity, you must consider the direction and find the resultant velocity, whereas with mass, you can just add their magnitudes.
I got 0.73 using suvat for the time taken down the ramp.
For the u^2 graph, the gradient i calculated was 16. Since 2a=m, m/2 = a, so acceleration was 8. It was then a simple F=ma question, giving you 7360N, or 7400N.
For the density, it was 7500, this was long, and hard, for sure.
What did y'all get for the wave equation one?
I forgot what I put for momentum, but I probs got it wrong.
Mean drift velocity was something *10^5 I think, quite high for some reason.
For the last, last question the answer was N=2.9*10^15 electrons emitted.
Q20 of multiple choice was 15, and the uncertainty one a few questions back was 6.5.
All I really remember, i found it quite hard, and timings wern't great, definetly harder than past papers, and I would expect low boundaries.
Reply 472
[QUOTE=Darshhchiba;65124201]I got the same

How comes its 0.3 and not 3?
Original post by maryamkhawaja
was the power mcq change in rate of word done.
q2 w=FP
uncertainty= 6.5
angle of rafraction 49 degs
something u/2

the mcqs are bothering me alot. help


i put FQ, as work done is force multiplied by the distance moved in the direction of THAT force... So as w was going down the only work that could be done is down so it was WQ
Original post by Suat
How comes its 0.3 and not 3?


If you're talking about the uncertainty for the waves question, im pretty sure it was 3, but I didn't put it into my calculator properly so it bidmas'd ma ass and gave me 0.3 instead.
was this question paper from AQA❓
Reply 476
Original post by Rushi Patel
was this question paper from AQA❓


clearly says ocr
Original post by Ramoose
1) Can't really remember.
2) Can't really remember, but imagine the wave was shifted to the right, then you draw the arrow from A and B to the next wave, and you can find if it goes up or down.
3) Force on asteroid was 2 marks, you were supposed to talk about the reaction force it experiences from Newton's 3rd law when it pushes against the comet, and also how the comet pushes on the asteroid with it's own force.
4) Will probably drop you 2 marks since the point of the question was to find internal resistance, you may only drop 1 if they emphasize repeating the experiment, if you wrote about that.
5) LED question, the voltage was insufficient to light up the LED, and the diode was pointing the wrong way. To make the circuit work, reverse polarity on the battery or switch direction of diode, then say for the LED to light up you need a sufficient voltage above the threshold. (Read from graph)
6) XY is wavelength/2, you have to multiply by 2, not 4. Probably needed to mention tape measure or something.
7) Last question was about how resistance changes as voltage changes in a diode VI characteristic. The very last part was the calculate number of photons emitted from LED per second or something. Total 8 marks or so.

say
in
3) Could I have said about the impulse provided by the comet acting on it and decreases with the change of momentum
5) I was on a bout the graph we got given to describe
6) I thought that at first but I changed it stupidly
7) so are them 8 marks including the graph to be described?
Original post by teachercol
Ive done the paper and I'll post up my answers and mark scheme later today.
Its quite a tough one - still that means low grade boundaries.


Answers are now posted. I'm not allowed to post any of the questions!

http://www.thestudentroom.co.uk/showthread.php?t=4114965
(edited 7 years ago)
Original post by teachercol
Answers are now posted. I'm not allowed to post any of the questions!


where?

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