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# Feynman Diagrams ??? watch

1. 1) Sketch the feynman daigrams for the electromagnetic force between
-a proton and electron
-two electron

is it a simple p and e in and out with an virtial photon exchange in the middle ?

2) Also im copying my friends notes and she has written things like L=
B=
around her feyman diagrams, what do these mean ?

3) In both beta + decay and electron capture, a proton chaanges into a neutron. Describe how these two processes differ ?
mostly i got the answer right except one part of the answer which was
" in elctron capture the W+ boson decays into a beta- particle and a neutrino" but the feynman diagram in the textbook dosen't show a beta- partcle ??

thankyou for you help

_________________
Why so many questions ???
Well, this summer im on a mission to learn all of AQA AS physics, its a challenge but i have to, if i want to apply to the course i want. I love physics but without leasons things are not going to well so please help me !!!
2. 3) In beta+ decay, the equation is written: p->e(+) + v + n, so a proton DECAYS into 3 other particles, where as in electron capture, a proton changes into a neutron as a results of it INTERACTING with an antineutrino.
So in beta plus decay, a proton decays, and in electron capture a proton interacts with another particle.
A beta particle can also be written as 'e', because a beta particle is an electron
3. attatchment- an electron-electron interaction, and the 2nd attatchement is for a proton-electron interaction

2) i honestly don't know what L= or B= stands for, but i wouldnt worry about i, i didnt use them and i got an A for it.
Attached Images

4. if you need anymore help on physics AS, don't hesitate to pm me, i did it last year, and know pretty much the whole thing. however...i really don't like electricity in unit 1.
5. yeah same here - if you need help just ask.

I have just done that same syllabus this year and so far it has gone well (100% ums on unit1 and isa, hoping for same on unit 2)

Good luck with it!
6. I'd guess that L stands for lepton number and B stands for baryon number. Every interaction has to conserve lepton and baryon number iirc.
7. Yes it does.
8. (Original post by suneilr)
I'd guess that L stands for lepton number and B stands for baryon number. Every interaction has to conserve lepton and baryon number iirc.
Nope.
Baryongenisis is the process of breaking the symmetry in Baryon number.
9. (Original post by suneilr)
I'd guess that L stands for lepton number and B stands for baryon number. Every interaction has to conserve lepton and baryon number iirc.
They'll teach you otherwise next year
10. (Original post by Mehh)
Nope.
Baryongenisis is the process of breaking the symmetry in Baryon number.
(Original post by ashy)
They'll teach you otherwise next year
Is nothing sacred anymore?

How bad is third year compared to second year? I'm hoping not too much harder...Also which lab options are the most interesting/easiest?
Thanks
11. (Original post by suneilr)
Is nothing sacred anymore?

How bad is third year compared to second year? I'm hoping not too much harder...Also which lab options are the most interesting/easiest?
Thanks
I won't lie to you; it's a lot more work and the concepts are quite a lot more advanced. Doable though, obviously.

I did Hall Effect, Radiation Laws and Boltzmann Constant by PN Junction.

I recommend the last two - the Hall Effect is a huge amount of very tedious work. Radiation laws took about 1/3 of the time it was meant to, and PN Junction is fine once you've done Solid State Physics.
12. (Original post by ashy)
I won't like to you; it's a lot more work and the concepts are quite a lot more advanced. Doable though, obviously.

I did Hall Effect, Radiation Laws and Boltzmann Constant by PN Junction.

I recommend the last two - the Hall Effect is a huge amount of very tedious work. Radiation laws took about 1/3 of the time it was meant to, and PN Junction is fine once you've done Solid State Physics.
I guess that means my social life will fall to 0 next year then....

Oh right. Do you have any idea what the microprocessor lab thing is like? It seems kind of interesting but also quite complicated. I'll probably end up asking you about labs when I come to do it and realise I have no clue as to what's actually going on
13. (Original post by suneilr)
I guess that means my social life will fall to 0 next year then....

Oh right. Do you have any idea what the microprocessor lab thing is like? It seems kind of interesting but also quite complicated. I'll probably end up asking you about labs when I come to do it and realise I have no clue as to what's actually going on
Just noticed my stupid typo >.<

I didn't do it but it covers two labs, so you only have to do one experiment. If you're good at programming then it's worth looking at, but I avoided it like the plague

I actually found 3rd year labs the most enjoyable
14. (Original post by ashy)
Just noticed my stupid typo >.<

I didn't do it but it covers two labs, so you only have to do one experiment. If you're good at programming then it's worth looking at, but I avoided it like the plague

I actually found 3rd year labs the most enjoyable
oh right. I don't mind programming. It's more the electronics that worries me. That's good to hear as I hate labs lol. I wasn't expecting to be doing labs next year since I was on theoretical but I decided to change at the last minute What options did you do, and how did you find them?
Woops I seem to have kind of hijacked this thread....
15. (Original post by suneilr)
oh right. I don't mind programming. It's more the electronics that worries me. That's good to hear as I hate labs lol. I wasn't expecting to be doing labs next year since I was on theoretical but I decided to change at the last minute What options did you do, and how did you find them?
Woops I seem to have kind of hijacked this thread....
I'm not really qualified to advise on the microprocessor course to be honest I know you have to learn assembly code.

I did Atmospheric Physics, Astrophysics, Sun Stars and Planets and Entrepreneurship. I do not recommend Atmospheric as it involves some vector maths which will melt your brain: rotating frames of reference and pain like that (ignore the fools who say there's no such thing as the centrifugal force!) It is a 4th year option though. Astro is cool. SSP is really cool (definitely do a level 2 option if you do a level 4). Entrepreneurship isn't great to be honest.
16. (Original post by ashy)
I'm not really qualified to advise on the microprocessor course to be honest I know you have to learn assembly code.

I did Atmospheric Physics, Astrophysics, Sun Stars and Planets and Entrepreneurship. I do not recommend Atmospheric as it involves some vector maths which will melt your brain: rotating frames of reference and pain like that (ignore the fools who say there's no such thing as the centrifugal force!) It is a 4th year option though. Astro is cool. SSP is really cool (definitely do a level 2 option if you do a level 4). Entrepreneurship isn't great to be honest.
Fair enough.

Hmm I'm considering doing advanced classical physics, lasers optics and biophotonics, optical communication physics, computational physics and foundation of quantum mechanics. I'm guessing that these options are going to be quite masochistic? Do you know anything about how people found these courses?
17. (Original post by suneilr)
Fair enough.

Hmm I'm considering doing advanced classical physics, lasers optics and biophotonics, optical communication physics, computational physics and foundation of quantum mechanics. I'm guessing that these options are going to be quite masochistic? Do you know anything about how people found these courses?
Computational physics is rape, I heard, with a separate exam in January and lots of coursework. ACP was the farcical exam this year where people thought they'd be lucky to pass. I reproduce here an excerpt from the email of complaint sent to the department:

As I'm sure any of you who were in this mornings exam are aware, the questions set were way above the standard of the course, the problem sheets, and any of the past papers from the last 5 years. As a result of this I have received many emails regarding how a lot of us felt this was unacceptable. Personally, I agree; I believe setting an exam completely beyond the scope of the course is not only disrespectful, but simultaneously a display of the arrogance of certain members of the department who apparently have nothing but contempt for the student body.
Make of that what you will

I don't know much about the other courses, to be honest. It sounds like a fairly rapey set of courses, but if they're subjects you like then I don't see why not
18. (Original post by ashy)
Computational physics is rape, I heard, with a separate exam in January and lots of coursework. ACP was the farcical exam this year where people thought they'd be lucky to pass. I reproduce here an excerpt from the email of complaint sent to the department:

Make of that what you will

I don't know much about the other courses, to be honest. It sounds like a fairly rapey set of courses, but if they're subjects you like then I don't see why not
Maybe I should just kill myself now I was originally planning on doing pretty much all the theory options because that's what I'm interested in, but I've decided that careers-wise I want to go into some kind of engineering probably weapons science hence the change to more applied modules Hopefully I'll be able to cope with them. Thanks for all the help. I'll probably be pming you for lab help in a few months though
19. (Original post by suneilr)
Maybe I should just kill myself now I was originally planning on doing pretty much all the theory options because that's what I'm interested in, but I've decided that careers-wise I want to go into some kind of engineering probably weapons science hence the change to more applied modules Hopefully I'll be able to cope with them. Thanks for all the help. I'll probably be pming you for lab help in a few months though
No problem. I'm just telling you what little experience I have of the other courses - I could be way off the mark.

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