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# AQA Physics PHYA5 - 28th June 2016 [Exam Discussion Thread] Watch

1. (Original post by Ainsleyy)
are you sure?!
Yeah this is right I came across it today, d is the distance

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2. (Original post by HandsomeRakk)
Although the text books don't there are some notes that AQA have made instead of a textbook, much better IMO. They are written in a much better way and made easily understandable with much less BS filler like every other aqa textbook!
Where can I find this? Is there one for turning points?
3. What time is everyone going to sleep? Still got some cramming to do
4. (Original post by nnblccz)
Fancy quickly summarising the tunnelling microscope?
sorry only just saw this, gimme a sec
5. (Original post by Ainsleyy)
What time is everyone going to sleep? Still got some cramming to do
2 is my planned nap time.
6. Can someone please explain what the "k" is in the gamma radiation equation? So confused lmfao
7. (Original post by jatt1997)
Can someone please explain what the "k" is in the gamma radiation equation? So confused lmfao
It's a constant . K = nhf/ 4pi
8. (Original post by ChillGod)
Where can I find this? Is there one for turning points?
https://e301d5e52e4368a053856306f647...20Electron.pdf

https://e301d5e52e4368a053856306f647...%20Duality.pdf

https://e301d5e52e4368a053856306f647...Relativity.pdf
9. (Original post by HandsomeRakk)
Although the text books don't there are some notes that AQA have made instead of a textbook, much better IMO. They are written in a much better way and made easily understandable with much less BS filler like every other aqa textbook!
Where?!?!
10. (Original post by Notions97)
It's a constant . K = nhf/ 4pi
what does each thing mean apart from the 4pi lol. Like can you give an example of a question please
11. (Original post by Notions97)
Where?!?!
Ive sent links but TSR taking their time to moderate
12. Turning points people: How does a glow occur on a discharge tube? I know it invoves electrons being excited, but for the electrons or gas atom electrons?

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13. (Original post by nnblccz)
Fancy quickly summarising the tunnelling microscope?
Scanning tunnelling microscope
-Fine tipped probe scans over the surface of a material atom by atom
-electrons tunnel across, inducing a current in the probe
-tunnelling current increases if the gap is made smaller (by a raised atom) and decreases if the gap is made larger (by dip in atoms)

There are 2 settings on STM
-Constant height mode-
The height of the probe remains constant and the change in current caused by the varying height of the surface is used to produce an image of the atom structure
-Constant current mode-
Piezoelectric transducers (god i love that word) respond to the change in current by adjusting the height of the probe so that the current is kept constant. The changes in height of the probe are used to form an image of the surface atoms.

-The wave nature of electrons is what allows them to tunnel across the gap, Their De Broglie wavelength is sufficiently large to stretch across the gap giving electrons a finite chance of crossing.
14. (Original post by Yo12345)
Turning points people: How does a glow occur on a discharge tube? I know it invoves electrons being excited, but for the electrons or gas atom electrons?

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The electrons excite the gas atoms, when the gas atoms de-excite they release photons which causes them to glow.
15. fxck this im going to bed, lets just pray for the morning
16. (Original post by jatt1997)
Ive sent links but TSR taking their time to moderate
i dont think they will moderate it by tonight. Took them a day to moderate mine. Tell him what to google or something
17. (Original post by Notions97)
Where?!?!
Right if you go on physics and maths tutor, Go to physics revision, then you will see a bunch of textbooks for the optional subjects. Chose D1 D2 D3 if you are doing turning points. Other textbooks are on there too
18. (Original post by jatt1997)
Right if you go on physics and maths tutor, Go to physics revision, then you will see a bunch of textbooks for the optional subjects. Chose D1 D2 D3 if you are doing turning points. Other textbooks are on there too
Love you thanks so much!!
19. (Original post by jatt1997)
what does each thing mean apart from the 4pi lol. Like can you give an example of a question please
Can't give an example of a question I'm afraid but hopefully this makes sense.

For a point source that emits n photons per sec, each with energy hf , the radiation per enegrry per sec = nhf.

At a distance r from the source, all photons emitted from the source pass through a total area of 4pi r ^2 ( surface area of sphere with radius r because gamma radiation is emitted In all directions so like a sphere)

So intensity is radiation enegrry per sec divided by total area which means
I= K/ r^2 so hopefully you can see that k is nhf/ 4 pi
20. What is the point

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