QUANTA - QUARKS... wtf?!?! (1 Viewer)

EXA BOY

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did anyone else find this option extremely difficult??? the 7 mark question i didnt even know neutron scattering was in the silly Bus!!!!!! wats the deal?!?!?! and there were 2 other hard 3 mark qns aswell!!! wat a gay option!!!
 

Bug

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I agree !!!!

What did people put for B III ??

The rest was fairly easy but the marking scale is very wierd !!!
 

blake

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I SO AGREE!

QUANTUM TO QUARKS WAS HAAAARD


hehe


"Not Attempted"


*/me walks out*
 

BlackJack

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Me & Lake practised on it during the days before... :) It was just in time, when I spotted it buried deep and vague... Of course that's assuming I know what neutron scattering means...:D

Fermi's work on distribution of KE of electron also helped a bit (though I didn't remember the exact reason...)
That wuestion is a problem, because only some of the textbooks have information on that... it was in none of mine, except in Jacaranda which we can't officially borrow . :p (McLake stealed the teacher's copy... damn you...:p)

edit: oh, there it is... "marsden" notes...
 
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EXA BOY

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i got that jacaranda aswell hehehe stole it from james ruse hahah thanks mum!! ummmm but my summaries were ON THE SYLLABUS so i didnt even read the section on neutron scattering... didnt see the need 2 CAUSE ITS NOT IN THE SYLABUS!!!!! im so dirty bout that as u can prob tell..... grrrrr
 

Bug

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I have the Excel HSC physics text book, it has half a page on neutron scattering. Given that it is 7 marks i suspect it's 3 marks for neutron scattering and 4 marks for the "other process that have been used to increase our understanding of the structure of matter" .... I did atom smashers.

I think i'll only get 3 or 4 marks for that question.

* The marks may be the other way around .... but i'm pritty sure it's 3 and 4 marks.
 

EXA BOY

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it mite b discussed in the text books..... but there is NO dot point relating to it!!! if u can find me the one that says "describe neutron scattering" then tell me... cause i got every dot pt summarised with the words of the syllabus and it doesnt mention it i cant believe they can test sumthin that isnt there?!?!?!?! stupid idea 2 me... the other method is ok though i killed that part but i cant get 7 cause i wrote like 2 sentences on neuton scattering and i called it neutron bombardment anywayz cause i didnt know wat it was
 

Bug

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Neutron scattering is in there.

9.8.5.4:
Explain why neutron scattering is used as a probe by referring to the properties of neutrons.
 

-=«MÄLÅÇhïtÊ»=-

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for (b) (iii), what was the reason for the maximum at that point?

and i had to make up some bs about (c)(i) coz i didnt fink my response was gonna gain 3 marks.
 

ske

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say what?...i thot u were spozed to work out the energy of the neutrino n explain the lost energy went into that..so were spozed to explain the graph?..coz i jus explained onli the beta decay reaction they gave us...eeeeeeh ><..there goes 3marks i guess...:rolleyes:
 

BlackJack

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I'll post here for the maximum...
It's complex, I bitched about it then because I didn't get the info I needed in my textbooks...

I had to assume gaussian distribution (bell-shaped curve) would be the norm for all multi-particle collisions, (it's based on laws involving average kinetic energy for particles in air... related to diffusion, etc.) beta-decay is a collision, in a sense. (you see the non-syllabus stuff I had to write?)

I fudged some of the answer, and just stated reasons why most of the parrticles had to have much less than the maximum. These include: some beta-decays release EMR, up to gamma wavelength / There's a second particle involved, the antineutrino, which must also share in the energy, and all neutrinos are observed to travel very fast / In conditions where both laws of conservation held, I thought the relationship of 1/2 mv^2 and mv meant that particles would be likely have a low velocity instead of a high one.

I need somebody with a real answer... where's spice girl :D?
 

spice girl

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Originally posted by -=MLhtʻ=-
for (b) (iii), what was the reason for the maximum at that point?
Well, the reason for the peak is out of our syllabus. If you really wanna know:
http://230nsc1.phy-astr.gsu.edu/hbase/quantum/fermi2.html

PS: i've nfi about what it all means...dun ask me. I just wrote: "it can be worked out by mathematics developed by Fermi.."

Wrong? then no one'll get it right...(i think)
 
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McLake

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Originally posted by spice girl

Wrong? then no one'll get it right...(i think)
That's a little conceted (even if it IS true ...)

I said most would be less than max due to energy lost as heat and sound ...
 

spice girl

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anyways
my guess as to what we have to write for that question:

* a continuous distribution of energies
* always less than 1.16 MeV (because of conservation of energy: beta energy <= mass defect)
* explained by Pauli's neutrino: energy of mass defect "shared" by ejection of both neutrino and beta particle.

i dun think a maximum comes into it...(i think). Otherwise, I'm stuffed for one mark...
 

The BrickSh*ter

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ARRRRRG

Sadly i looked after and the neutron scattering IS in the syllabus. However the general exam was pretty easy I left after 2 hours

I looked at the age of silcon questions and i could have done better in that option than quanta to quarks....




anyway 2 days till drinking time :);)
 

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