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# Official Thread For OCR Physics A G484 Jan 2011 Watch

1. (Original post by TinySnowflake)
I think I got 8. something for the number of moles, and for the mass I got something around 0.023?
Sorry can't remember the exact values..
Before i meant 0 to -18, and i had the same for the last two. 8.35 and 0.023
2. Much harder than the Jan 10 june 10 papers, id say 44 for an A
3. (Original post by TinySnowflake)
I think I got 8. something for the number of moles, and for the mass I got something around 0.023?
Sorry can't remember the exact values..
This
4. what did everyone write about in the brownian motion question
5. (Original post by yash123A)
what did everyone write about in the brownian motion question
That it showed molecules moved in random chaotic motion, and had collisions ect.
6. (Original post by nirvana001)
Much harder than the Jan 10 june 10 papers, id say 44 for an A
I agree, hopefully lower the boundaries.
7. I got 112.5 for the speed of oxygen, 1800/16?
8. (Original post by yash123A)
what did everyone write about in the brownian motion question
first part i sed theyre in rapid, random motion.

second part i sed they are colliding with the air molecules and so the air molecules must also have random motion. then i mentioned that the speed of the air molecules is greater than that of the smoke particles as they have smaller mass. then i finished off by saying that they are moving

the calculation one i got as 450m/s
9. That was a ridiculous paper - easily harder than jan or june 2010. I was a bit stumped by the air momentum helicopter thing until I saw that it was "this" mass of air, then from there it was OK(ish). What did people get for the tide equation? I got 13 + sin(1.4 x 10E-4 t) (assuming t starts at mid tide as the tide is coming in), but realised after that it should have been 15.5 instead of 13 since that's the eq. position. Also, the kilowatt hour shocked me a bit - never in my life have I seen quite so bold a synoptic question!
10. can someone post the paper up, with the mark scheme? thanks
11. i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??
12. (Original post by TinySnowflake)
Did the question require you to put temperature values on the side?
I thought it said it didn't...
18, 0 and -18 were already there, it said you didn't need to add a scale to the time axis
13. (Original post by sc0307)
i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??
I got 13.2 or something for before, and then right down to 3. something after
14. (Original post by EmperorMustard)
I got 13.2 or something for before, and then right down to 3. something after
I got 13.2 down to like 3.2 or something, with momentum as 4/3
15. (Original post by nirvana001)
first part i sed theyre in rapid, random motion.

second part i sed they are colliding with the air molecules and so the air molecules must also have random motion. then i mentioned that the speed of the air molecules is greater than that of the smoke particles as they have smaller mass. then i finished off by saying that they are moving

the calculation one i got as 450m/s
I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.
16. this paper was a load of b****, seriously, the the helicopter question p**** the hell out of me, I tried every combination of numbers and couldn't get 6000, then realised at the end it said cylinder so didn't have time to do that

kilowatt an hour annoyed me, that's AS! argh

prob going to have to retake ;/ it's on the 27 June aswell dam.
17. i got 481ms-1

firstly i used E=3/2 kT for one molecule

then multiplied by avagadros constant for one mole

plugged that into E=1/2mv^2 to get the speed

is this how everyone else done it??
18. (Original post by sc0307)
i got 481ms-1

firstly i used E=3/2 kT for one molecule

then multiplied by avagadros constant for one mole

plugged that into E=1/2mv^2 to get the speed

is this how everyone else done it??

I did 1/2mv^2 for hydrogen, used that energy for oxygen, and used 1/2mv^2 again to find v

got 450

(Original post by FruitsPunchSamurai)
I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.
really, I'm sure it's 5???
19. amplitude for the harbour question?

surely it was 18m cos that was the maximum depth?
20. (Original post by yash123A)
what did everyone write about in the brownian motion question
My 3 points (3 marks):

-Random,chaotic motion
-Intermolecular collision
-Proof of kinetic gas theory therefore the molecules exert a pressure.
(Original post by sc0307)
i was so stretched for time!

did anyone else get 13.2 for the total energy before and 13.1 for the total energy after??
I got 13.2J down to 3.2J,therefore inelastic.

(Original post by FruitsPunchSamurai)
I got that as well, but when I was working out temperature in that question, I got a ridiculously large number. 1.5x10^26, I was thinking, "How is that even remotely possible?"

I got 2.5 for the amplitude question.
Also got 2.5 for amplitude, good to know

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