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# OCR PHYSICS B G495~ 18th June 2015 AM ~ A2 Physics watch

1. (Original post by STATER)
What exactly were they asking for in question 3 (the one about fields that had a straight line graph)?
I said the field was uniform shown by the straight line through the origin, and did two calculations which ended up as 4.2x10^3 and 4.3x10^3. Really was unsure what to do tbh.
I put that it non uniform as electric potential should be inversely proportional to distance, and it wasn't.
2. (Original post by STATER)
Mass was not conserved since a gamma photon was released.
Gamma photons have no mass!!!!

It was charge. Alpha particles are charged.
3. (Original post by RealTime)
Yeah I think that's correct, I also got that too
how did you do it? :/i did it quite a funny way and got the correct answer just wondered what people's methods were since my graphical calculators didn't show gamma to enough decimal places so I had to use an old fashioned calculator haha!
4. (Original post by McCustard)
Did anyone else get 2312K for the temperature for 3N electrons per second? It took me forever!
Also now I'm worried that I didn't read it properly and can't remember if it wanted the increased temperature or how much it had increased by
I got that too, but I don't know if that's right or not.
5. (Original post by McCustard)
Did anyone else get 2312K for the temperature for 3N electrons per second? It took me forever!
Also now I'm worried that I didn't read it properly and can't remember if it wanted the increased temperature or how much it had increased by
Yes I did , you used the fact that current was proportional to the boltzmann factor and my calculation involved logging both sides haha but yeah i got exactly that and it seems correct to me! worked through it logically so should get the marks!
6. (Original post by Minecraft27)
I got that too, but I don't know if that's right or not.
yes since number of electrons released was proportional to current so you did current*3 and this equal the BF so you then log both sides and get that answer for T
7. (Original post by Minecraft27)
Gamma photons have no mass!!!!

It was charge. Alpha particles are charged.
Wasn't it quarks

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8. (Original post by HennersPD)
how did you do it? :/i did it quite a funny way and got the correct answer just wondered what people's methods were since my graphical calculators didn't show gamma to enough decimal places so I had to use an old fashioned calculator haha!
I calculated the Lorentz factor (gamma) and then rearranged the formula for calculating the Lorentz factor which involved v and made v the subject
9. What did you guys get in the 4 marker about the accurate representation of the decay particles in a magnetic field?

I worked out their deflection radii and found that beta particles in reality have a radius 200 times smaller than an alpha decay particle and wrote about how the diagram was inaccurate for only showing beta particles as having slightly less radius etc etc.

PS: What thing is not conserved? I wrote charge, because alpha particles are charged.
10. (Original post by Mutleybm1996)
Wasn't it quarks

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i think i put charge since an alpha particle is charged!
11. (Original post by Minecraft27)
Gamma photons have no mass!!!!

It was charge. Alpha particles are charged.
Gamma photons have energy. E=mc^2. Energy released = mass lost.
12. (Original post by RealTime)
I calculated the Lorentz factor (gamma) and then rearranged the formula for calculating the Lorentz factor which involved v and made v the subject
ah yeah thats what i did good!
13. (Original post by Minecraft27)
What did you guys get in the 4 marker about the accurate representation of the decay particles in a magnetic field?

I worked out their deflection radii and found that beta particles in reality have a radius 200 times smaller than an alpha decay particle and wrote about how the diagram was inaccurate for only showing beta particles as having slightly less radius etc etc.

PS: What thing is not conserved? I wrote charge, because alpha particles are charged.
yeah i did the same should get the marks! also said that beta particle should have less deflection than shown by the diagram!
14. (Original post by HennersPD)
yeah i did the same should get the marks! also said that beta particle should have less deflection than shown by the diagram!
Shouldn't it have much much more?
15. (Original post by STATER)
Gamma photons have energy. E=mc^2. Energy released = mass lost.
What was the equation? Wasn't it an alpha decay?

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16. Did anyone else write Charge for the thing that isn't conserved.

It's not quarks because there are no free quarks.
It's not mass because photons have no mass.
And I can't remember what the other thing was.

@post 295, a gamma photon was released too.
17. (Original post by Minecraft27)
Did anyone else write Charge for the thing that isn't conserved.

It's not quarks because there are no free quarks.
It's not mass because photons have no mass.
And I can't remember what the other thing was.
Other thing was nucleon number?

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18. What did everyone get for the minimum X-ray wavelength? I got something like 3.3x10^-11 metres but I don't remember exactly.
19. (Original post by Rhetorical Hips)
What was the equation? Wasn't it an alpha decay?

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I don't remember exactly. It had an electron and an antineutrino. Also the question said that a photon was released which I remember well because I highlighted it
20. (Original post by Minecraft27)
What did everyone get for the minimum X-ray wavelength? I got something like 3.3x10^-11 metres but I don't remember exactly.
Yes thats correct

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