PHYA1 - Physics Unit 1 Exam - 24th May 2011

Original post by questionandanswer

Questions I can remember:
1. Proton , Neutron
2. The second equation can't happen -lepton number not conserved
3 X is a baryon as a to conserve baryon number
4. Specific charge was 4.79x10^7 Ckg-1
5. 6 marker on excitation of atoms
6. Ionisation is min energy required to remove electron from atom in a gaseous state
7. Internal resistance was 0.488ohms
8. Power was 0.355W
9. 5ohms was total resistance
10. Proof that resistors were 3
11. 1.33A
12. 2V
13 emf=1.52V
14. Neutrino needed to preserve lepton number
15. Electron capture

Any more?

How sureare you power was 0.355W ? because i got that and rounded to 0.36w. Its the only numerical answer I was concerned with.

Reply 442

I'm fairly sure it was the right answer, just not sure of sig fig

Reply 443

Original post by joe5494

didn't you have to prove resistance was 5?
as it was
1/(1/3 +1/6) +3
is 5 :smile:

i did that! :smile:

Reply 444

Original post by Notsocleverstudent

Is anyone aware if AQA mark down for significant figures?

yes they do, but only on the questions that specifically state 'to an appropriate degree of accuracy'

Reply 445

harrywhiterose

for the feynman diagram i put a photon symbol for the exchange particle, is this right or not?

Reply 446

Msd27

1

Original post by maths134

How sureare you power was 0.355W ? because i got that and rounded to 0.36w. Its the only numerical answer I was concerned with.

dont think they will be too bothered about sig fig.. i cant remember them asking to an appropiate number of sig figs... or did they? :tongue:

Reply 447

Original post by Msd27

Okay so lepton number has to be conserved in the interaction.... lepton number on right hand side = 0 therefor the lepton number on righthand side has to also equal 0 therefor as a positron is emmited that has a lepton number -1 therefor the other particle has to have lepton number +1 therefor electron neutrino not anti electron neutrino :biggrin:

what about charge? :smile:

Reply 448

Some of the data was 3sf, so I did 3

Also: the exchange particle was a W+ boson

Reply 449

Original post by questionandanswer

I'm fairly sure it was the right answer, just not sure of sig fig

how did u calculate it. I realised u could just do P=.... at the end and in the exam but did it quite long winded lol. Basically used the I=Q/T equation from the question before. Divided that by 15 to get coloumbs per second. Then used my internal resistance and the current given to calculate V (V=IR). Then used all of this in the V=W/Q. hmm I did get that answer tho lol

Reply 450

Original post by harrywhiterose

for the feynman diagram i put a photon symbol for the exchange particle, is this right or not?

i think it was a W+ boson, im not sure :smile:

Reply 451

Original post by harrywhiterose

for the feynman diagram i put a photon symbol for the exchange particle, is this right or not?

Wrong it was a W+

Reply 452

Original post by littleprecious

what about charge? :smile:

Neutrinos and antineutrinos aren't charged so they dont come into it

(side note: as they're not charged, they're very difficult to detect)

Reply 453

Original post by maths134

how did u calculate it. I realised u could just do P=.... at the end and in the exam but did it quite long winded lol. Basically used the I=Q/T equation from the question before. Divided that by 15 to get coloumbs per second. Then used my internal resistance and the current given to calculate V (V=IR). Then used all of this in the V=W/Q. hmm I did get that answer tho lol

P=IsquaredxR
0.89squared x 0.448

Reply 454

Original post by Alex J

for the quality of a strangeness i put: "a strance particle has a non-zero value for strangeness"

i put that strangeness is only conserved in strong reaction, not sure if thats right tho :smile:

Reply 455

Original post by questionandanswer

P=IsquaredxR
0.89squared x 0.448

now you see, this would have saved me a great amount of time. I believe my method is still valid however.

Reply 456

harrywhiterose

ok its just 1 mark anyway haha, and 2 more things, what did u put for the 6 mark question, and what did u put in the argon thingy with the positron emmision or summet ???

Reply 457

Msd27

1

Original post by littleprecious

what about charge? :smile:

both the electron neutrino and electron anti-neutrino are uncharged therefor you cant use charge conservation law to decide which one it should be :frown:

Reply 458