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PHYA5 ~ 20th June 2013 ~ A2 Physics

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I said used furl rods for the source. Donno if it is correct...

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What did people think of the applied paper?

Boundary predictions?


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Original post by MSI_10
IMO hardest unit 5 paper anyone agree? :/

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Harder than all of them except for jun12

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Original post by Jam Jam24
That question pissed me off. We learned that moderators slow down neutrons. So how is it elastic?? I just put down what i learned that kinetic energy of the neutrons decreases and gets trannsfered to the moderator atoms but no clue


It's elastic because a lot of the every is given to the moderator nuclei.
Yeah I was stumped when they asked about elastic collisions in the moderator... Wtf?

And what is an ideal gas?
Reply 1505
Avatar for Elton
Elton
To anyone who did the Medical Option, did you include any specific values for how much the force or pressure is amplified by in the 6 mark question on the ear or did you just explain when and how it's amplified by each part of the ear?
What did everyone get for the value of V for the point where 2m0 is on the graph?
Original post by Jam Jam24
What did everyone get for the value of V for the point where 2m0 is on the graph?


2.(6 or 8)x10^8
Reply 1508
Avatar for mrwho
mrwho
Original post by bugsuper
Definitely the used fuel rods. They're CRAZY radioactive.


Why didn't I put that? For some reason I thought the question was asking about the fuel rods, so you didn't have to say it and instead talked about an excess of neutrons, but in retrospect that was really really stupid. What an idiot. That's 1 or 2 marks I easily could have got.
Original post by study beats
38 marks for a B?


I already have 367UMS, therefore i need 53UMS to get a B overall. So i would say with a solid 38, and however many more i doubted myself for, this should get me in.
Original post by Pinkhead
Yeah I was stumped when they asked about elastic collisions in the moderator... Wtf?

And what is an ideal gas?


I said "A gas that obeys Boyle's law, the Pressure law, and Charles's law. It is a theoretical model used to model real gases."

I've since looked it up and a popular definition online is "a theoretical gas that obeys Boyle's Law at all temperatures" or words to that effect. So hopefully I'll get half marks
Original post by mrwho
Why didn't I put that? For some reason I thought the question was asking about the fuel rods, so you didn't have to say it and instead talked about an excess of neutrons, but in retrospect that was really really stupid. What an idiot. That's 1 or 2 marks I easily could have got.


You're right, they were talking about the spent fuel rods i.e the neutron rich daughter nuclei, saying fuel rods doesn't mean anything.
And just like that all hope for an a* was lost....
Reply 1513
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mrwho
Original post by SpiggyTopes
The neutron passes Ek on to the moderator, and slows down to become a thermal neutron after about fifty collisions.


How is that 'elastic'? I said that because I had no idea, but it goes explicitly against what was stated in the question.
Reply 1514
Avatar for Christd
Christd
Original post by Pinkhead
2.(6 or 8)x10^8


yup i got 2.6x10^8 ms^-1
what did the graph look like?
Reply 1515
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Kenna
What did people get for the energy release on the 1st question? I think mine was around 230 Mev.... can't remember exactly.
Original post by Beth_L_G
Yeah I only need 60 ums in this for my b so should be ok (fingers crossed)


Yeah, it's such a nice feeling! Ouch at 120UMS for an A.... I did re-sit Unit 4 to try for the A but i haven't done it. I'm over the moon with a B though, i haven't found it easy this year.
Reply 1517
Avatar for Hullo
Hullo
8
Original post by Pinkhead
Yeah I was stumped when they asked about elastic collisions in the moderator... Wtf?

And what is an ideal gas?


Ideal gas with molecules which are identical, no intermolecular forces, negligible volume and random motion :confused:
Original post by Christd
yup i got 2.6x10^8 ms^-1
what did the graph look like?


massenergy.gif
Original post by Kenna
What did people get for the energy release on the 1st question? I think mine was around 230 Mev.... can't remember exactly.


I got like 27 or something, so youre probably fight :P

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