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

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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?

Reply 601

Ainsleyy

What time is everyone going to sleep? Still got some cramming to do :frown:

Reply 602

splashywill

Original post by nnblccz

Fancy quickly summarising the tunnelling microscope?

sorry only just saw this, gimme a sec

Reply 603

Will2610

Original post by Ainsleyy

What time is everyone going to sleep? Still got some cramming to do :frown:

2 is my planned nap time.

Reply 604

jatt1997

Can someone please explain what the "k" is in the gamma radiation equation? So confused lmfao

Reply 605

Notions97

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

Reply 606

jatt1997

Original post by ChillGod

Where can I find this? Is there one for turning points?

https://e301d5e52e4368a053856306f6475860b017e094.googledrive.com/host/0B1ZiqBksUHNYemtzOWdnbGVnRVk/Textbooks-for-Options/D1%20Discovery%20of%20the%20Electron.pdf

https://e301d5e52e4368a053856306f6475860b017e094.googledrive.com/host/0B1ZiqBksUHNYemtzOWdnbGVnRVk/Textbooks-for-Options/D2%20Wave-Particle%20Duality.pdf

https://e301d5e52e4368a053856306f6475860b017e094.googledrive.com/host/0B1ZiqBksUHNYemtzOWdnbGVnRVk/Textbooks-for-Options/D3%20Special%20Relativity.pdf

Reply 607

Notions97

Original post by HandsomeRakk

Where?!?!

Reply 608

jatt1997

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

Reply 609

jatt1997

Original post by Notions97

Where?!?!

Ive sent links but TSR taking their time to moderate

Reply 610

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?

Posted from TSR Mobile

Reply 611

splashywill

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.

Reply 612

splashywill

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?

Posted from TSR Mobile

The electrons excite the gas atoms, when the gas atoms de-excite they release photons which causes them to glow.

Reply 613

WillRose

fxck this im going to bed, lets just pray for the morning :biggrin:

Reply 614

Ainsleyy

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 :smile:

Reply 615

jatt1997

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

Reply 616

Notions97

Original post by jatt1997

Love you thanks so much!!

Reply 617

Notions97

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

What is the point

Just tried question 4b on june 2011 5d (turning points), I used normal Ek formula (ek = 0.5mv^2), and i just used the rest mass of a proton (938.257MeV) and worked out a ratio, ended up with 0.18 and the answer is 0.25. I realise this is completely the wrong method, but i have a few questions.

For special relativity equations. How do you know which 'reference frame' (e.g. a proton moving, and some detectors) is the L =.... and which one is the L0 (subscript) part? Like how do you know which reference frame is the normal length or speed or time, and which one is the Lorentz form length, speed or time (contracted - where you use the spec rel equations) (if that makes sense).

Thanks

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

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