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# OCR PHYSICS B G491~ 19th May 2015 AM ~ AS Physics watch

1. anyone know how to answer this question form Jan 2013 Question 4? I can't seem to get my head around it! :/
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2. (Original post by IIEquinoxII)
In the examiners report for last years paper they admit that they messed up big time, and noted that the timing was way off. Im 99% sure this paper will not be anywhere near as hard
" Timing was an issue for some candidates on this paper, which may have been slightly more
demanding than some previous papers in the series. Some candidates seemed thrown by a
slightly new context, the digital QR codes in Q.10, but they should expect to apply their physics
knowledge (digital information) to novel contexts in the examination.
"

http://www.nooooooooooooooo.com/
3. (Original post by HennersPD)
anyone know how to answer this question form Jan 2013 Question 4? I can't seem to get my head around it! :/
What a coincidence, I just did this paper today myself.

It's really quite simple, you take the frequency of a harmonic other than the first, and divide to find the fundamental frequency.

Harmonics are multiples of the fundamental frequency. Therefore the fifth harmonic is five times the fundamental frequency.

Using a higher harmonic will decrease the % uncertainty of the frequency reading.

As for the second part, the peaks will just decrease in amplitude whilst staying in the same position.

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4. (Original post by HennersPD)
anyone know how to answer this question form Jan 2013 Question 4? I can't seem to get my head around it! :/
400/5=80

Wait, answer is 77...no idea how

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5. (Original post by HennersPD)
anyone know how to answer this question form Jan 2013 Question 4? I can't seem to get my head around it! :/
This was such a silly question imo, if I remember correctly you estimated the value of each each peaks frequency over several peaks, added them then divided it by how many however many peaks you used to get an average. Why they wanted an average I'm not too sure, it's marginally more accurate than reading just one value off a crude scale?

For part 2 of the question the frequencies of the peaks would be the same however the p.d they reached would be lower(smaller amplitude) as the sound is quieter = less energy = lower p.d
6. (Original post by SheLikeTheMango)
I feel like OCR B dumb down physics a bit too much, they say that the electrons in metallic bonding act as a 'glue'...
Well, yeah, they do though don't they, simply because they don't need you to use key word after key word doesn't mean that the course has been dumbed down.
7. Also, guys/girls - If I get an answer like 41080, should I write in the answer box 41080 , 4.10 x10^4 or 41000?
8. (Original post by Fangedbeast)
Also, guys/girls - If I get an answer like 41080, should I write in the answer box 41080 , 4.10 x10^4 or 41000?
I would write 4.11 x 10^4
Or 41100

Generally keep things at 3 s.f. unless told otherwise
9. (Original post by Mutleybm1996)
400/5=80

Wait, answer is 77...no idea how

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5th peak is around 380 Hz, so divde 380 by 5 as this is the 5th harmonic and you'll get 76 which is close to what they wanted
10. (Original post by Fangedbeast)
Also, guys/girls - If I get an answer like 41080, should I write in the answer box 41080 , 4.10 x10^4 or 41000?
As far as I'm aware (mother is a physics teacher teaching this course) they'll accept any, just ensure your rounding is sensible and correct
11. (Original post by Fandalf)
Just a quick question, why did everyone hate last year's paper? I did it as a mock and honestly I thought it was better than some of the previous papers.
I think many people hated the QR code question, i didn't mind it but a lot of people ran out of time etc before they could get their head round the novelty of the situation
12. (Original post by danthebox)
http://www.cram.com/flashcards/g491-...hysics-5861979

I HAVE JUST MADE A FLASHCARD SET ON CRAM REGARDING TOMORROW!

Yeah, these are pretty good. A few definitions are slightly different from what I've thought - but they're really worth a look!

Thanks for putting them up!!!!!
13. (Original post by terrytomlinson)
does anyone know of any good sites for materials revision?
These are great, and really helped me out
http://sam.davyson.com/as/physics/ca...view.php?n=4.0
http://sam.davyson.com/as/physics/ca...view.php?n=5.0

14. Why do we do height of E over height of A?

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15. good luck people!
16. (Original post by terrytomlinson)
does anyone know of any good sites for materials revision?
http://www.cram.com/flashcards/g491-...hysics-5861979
Flash card set i made earlier today! see what you think !!
17. soo scared for tomorrow!
18. (Original post by Emerald123)
soo scared for tomorrow!
i can't decide whether its gonna be a nice physics exam or a dreadful one!
19. (Original post by danthebox)
i can't decide whether its gonna be a nice physics exam or a dreadful one!
Sure it'll be the former!
20. In Jan 2011 the grade boundaries were the same as last year (38 for an A) and in June 2011 the paper was a lot easier and grade boundaries went up to 45. i got 44 in the Jan 2011 paper and 55 in the June 2011 paper so you increase your marks by about 20%. Hopefully the paper is easier this year. I predict stress and strain to come up as there was none of it last year. Also, there should be a lot of chapter 3 (signalling) as there was not much of it last year. I also expect polarisation to come up as it hasn't come up for a while. But this is looking at recent exam papers and it's always hard to predict questions so I could be completely wrong.

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