laser174572
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#541
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#541
(Original post by mrwho)
Thanks a lot - that's great.
Sorry to hear there's no Applied option stuff, if you e-mail the admins it might be a website error, it might be worth a try! But for the core there's still something like 100 pages of questions


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mrwho
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#542
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#542
(Original post by laser174572)
Sorry to hear there's no Applied option stuff, if you e-mail the admins it might be a website error, it might be worth a try! But for the core there's still something like 100 pages of questions


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I deleted that comment because it sounded rude, but I guess you saw it anyway! Apparently, though, applied comes under 'core', which I didn't realize. The 'packs' only had nuclear and not applied, but there's a bunch of past papers for applied physics from the old spec and that's great, so thanks again! I still don't see why applied physics isn't in the AQA revision book though.
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jackerharder
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#543
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#543
(Original post by Pinkhead)
Try reading through this, especially the bit under ''Moderation of Fast Neutrons''
http://hyperphysics.phy-astr.gsu.edu...ene/moder.html
Yes, I understand all of the moderation process, but I don't understand how the word 'scattering' can be linked to it? Does it just mean that the nuetrons released in fission go all different directions?
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bugsuper
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#544
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#544
(Original post by JRP95)
You Only need around 100?! What did you get in the ISAs and in unit 4?
I got 120 in Unit 4, and 58 in the ISA. I think it's 270/300 for an A*, so I guess that leaves me with 92 to get...
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smith50
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#545
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#545
Could anyone help me on this question please Name:  Capture.PNG
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Thanks,
Smith
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bugsuper
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#546
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#546
The process of decay into calcium is 8x more likely than the process of decay into argon. This means that, for every argon atom, you can assume there will be 8 calcium atoms somewhere.

The tricky part comes in interpreting these relative proportions:

If there are 5 potassium atoms for every argon atom, then we know that there must also be 8 calcium atoms (because of that argon atoms.) This means that, initially, when the rock was formed, there were 14 potassium atoms (5 that still haven't decayed, 8 that became calcium, and one that became argon.) Using the half-life of potassium, which I imagine was given you, you can work out how long it would take for 14 potassium atoms to decay into 5 in the usual way.
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cooldudeman
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#547
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#547
(Original post by bugsuper)
I got 120 in Unit 4, and 58 in the ISA. I think it's 270/300 for an A*, so I guess that leaves me with 92 to get...
Damnnn I got 57 in isa. Is that 54ums?

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bugsuper
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#548
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#548
I don't know the conversion rates off the top of my head, but they'll be on the AQA website (if you did it in January, anyway.)

It certainly won't be LESS than around 54 ums anyway
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JRP95
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#549
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#549
(Original post by bugsuper)
I got 120 in Unit 4, and 58 in the ISA. I think it's 270/300 for an A*, so I guess that leaves me with 92 to get...
Wow you've dropped only 2 ums this whole year so far... So you've basically got an A*
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fayled
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#550
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#550
(Original post by bugsuper)
I got 120 in Unit 4, and 58 in the ISA. I think it's 270/300 for an A*, so I guess that leaves me with 92 to get...
120UMS for me in unit 4 too, but we do the EMPA so I don't have the comfort of knowing my practical marks unfortunately. Also, I'm Oxford too
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bobthebuilder
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#551
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#551
anyone who does astro, can you help me out pls?
i'm slightly confused about the definition of a black body,
if it absorb all wavelengths of all electromagnetic radiation, how can it emit all wavelengths of em radaition too?
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amish123
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#552
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#552
(Original post by bobthebuilder)
anyone who does astro, can you help me out pls?
i'm slightly confused about the definition of a black body,
if it absorb all wavelengths of all electromagnetic radiation, how can it emit all wavelengths of em radaition too?
Thermal equilbrium I suspect, what energy it gains must be radiated to maintain this equilibrium. The radiation is emmited in accordance with Planck's law (black-body curve).
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amish123
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#553
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#553
(Original post by bugsuper)
I don't know the conversion rates off the top of my head, but they'll be on the AQA website (if you did it in January, anyway.)

It certainly won't be LESS than around 54 ums anyway
Hey, I got pretty much the same results as you so far in Physics at A2, has your ISA been moderated at all?
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bugsuper
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#554
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#554
(Original post by amish123)
Hey, I got pretty much the same results as you so far in Physics at A2, has your ISA been moderated at all?
I don't know about moderation, although I remember our Physics teacher very carefully explaining to us that grades may go up as well as down when we were given them. I think you only get your final grade in June, although I may be wrong... anyone know about ISA moderation procedures?
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JayJay95
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#555
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#555
Hey guys

Just wanted to ask, are we supposed to use the atomic mass of an electron when calculating the mass defect in the binding energy section?
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bugsuper
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#556
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#556
(Original post by JayJay95)
Hey guys

Just wanted to ask, are we supposed to use the atomic mass of an electron when calculating the mass defect in the binding energy section?
Since the changes of binding energy only apply to the nucleus, I doubt that you should - because the electron mass would presumably be conserved as electrons. Maybe if you were calculating the mass changes during electron capture, or something like that.
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JayJay95
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#557
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#557
(Original post by bugsuper)
Since the changes of binding energy only apply to the nucleus, I doubt that you should - because the electron mass would presumably be conserved as electrons. Maybe if you were calculating the mass changes during electron capture, or something like that.
Oh yeah that makes sense thanks

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ehtisham_1
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#558
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#558
Hey guys on the topic of moderation, our isas got moderated last year and they got marked down as we may have done did the experiment wrong, for whatever reason it ended up getting marked down from an A to an E, so you never know with is as unless your 100 percent you've done the experiment correctly and your teachers marked it right.

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Beth_L_G
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#559
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#559
Does anyone happen to have a copy of any of the past papers with the answers written on? I have written out answers on printed past papers but I'm a bit of a cripple and so can't be bothered to go upstairs and get them
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jimmy_95
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#560
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#560
What are your opinions on the isa grade boundaries this year? Do you think they will go up, down or remain the same as last year?
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