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AQA Physics: PHYA1 Tuesday 19th May 2015 (AM) and PHYA2 Thursday 04th June 2015 (PM)x

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Original post by MysteriousKnight

Hi Guys!
Guys I got a few question with the January 2013 paper

http://filestore.aqa.org.uk/subjects/AQA-PHYA1-QP-JAN13.PDF <- Paper

http://filestore.aqa.org.uk/subjects/AQA-PHYA1-W-MS-JAN13.PDF <- Mark scheme

Can someone explain 4Aiii) Where do they get the 1.63 x 10^-19 in the MS ... it seems as if I'm missing something quite simple out but can't figure out what :/

6B) the table ... How did they get 2V for C-D

Thanks :biggrin:

For 4a)iii) The kinetic energy after the collision is equal to the kinetic energy before - the kinetic energy it transfers to excite the electron.

Reply 21

joshohill

Original post by joshohill

Haven't got time to do 6B with you right now but you are right about 4aiii . youre missing something very simple. The energies given in the diagram are in eV. You must convert to J to do your calculation. 1J=ev * (1.6x10^19)

In 4 a ii you worked out by simple subtraction that the energy was = 10.19 ev. But you had to convert that into joules using the equation i mentioned above. (ev*1.6x10^-19). As 1.6 x10^-19 is charge on an electron. Ev is electron volts and 1 electron volt is the work done in accelerating an electron through a potential difference of 1 volt.

That would then give you 1.63*10^-18

In iii it gives you initial energy of electron before incidence and in first part of a ii you worked out how much energy was taken to promote the electron up a shell from n1 to n2. So just simply subtract lost energy from initial energy :smile:

Reply 22

rolypoly1997

Hey guys, seeing as this is a physics thread, how're you guys going about revising and prepping for the unit 3 EMPA and both its tasks? My teachers haven't really told us anything about it and I honestly have no idea what to revise!😭

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Reply 23

joshohill

Rules here say you cant discuss content so I will help you within what I can. Try to revise all of your basic knowledge. Just make sure you get your units right and tables and graphs are easy marks. Generally people perform well in empa tasks. Hopefully your teachers have told you to do past tasks from the aqa website.

(edited 9 years ago)

Reply 24

joshohill

Its against rules to know or discuss empa topics as you should not know the task. But as I said in terms of prep the onyl way you can prep is technique. Read examiners reports from past? Mark schemes?...

Reply 25

rolypoly1997

Okay will do! I would normally be a bit relaxed about it, but it's just that we haven't really done a mock and they haven't told us anything at all! But thank you so much for the advice! :smile:

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Reply 26

joshohill

No worries, just use the online resources :smile:

Reply 27

the_googly

bump

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Reply 28

crashMATHS

How's everyone feeling for unit 1? :tongue:

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Reply 29

PotterPhysics

Can someone explain question 8 part c here: https://d257ba8b9971d35b509279e471f1d8167ae3e7f0.googledrive.com/host/0B1ZiqBksUHNYZkdjdXdsZmZjX3M/From-AQA/1.2%20Quantum%20Physics.pdf

Thanks

Reply 30

crashMATHS

Original post by PotterPhysics

Can someone explain question 8 part c here: https://d257ba8b9971d35b509279e471f1d8167ae3e7f0.googledrive.com/host/0B1ZiqBksUHNYZkdjdXdsZmZjX3M/From-AQA/1.2%20Quantum%20Physics.pdf

Thanks

E to D and D to B.

To go between both of those energy levels, the same amount of energy has to be lost. Since energy is proportional to frequency, if they both require to lose the same amount of energy, they both will release a photon of the same frequency.

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Reply 31

PotterPhysics

Original post by kingaaran

Thanks! I missed the last part earlier, "of the same frequency," and was completely baffled for about 10 minutes. :wink:

Note to self: Re-read the question!

Reply 32

crashMATHS

Original post by PotterPhysics

Thanks! I missed the last part earlier, "of the same frequency," and was completely baffled for about 10 minutes. :wink:

Note to self: Re-read the question!

Indeed - every word counts with the unit one paper, I find.

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Reply 33

PotterPhysics

Original post by kingaaran

Indeed - every word counts with the unit one paper, I find.

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Yup, and don't misread questions either! If I had a penny every time that happened, I would be rich.

Reply 34

GrandMasti

How much do we need to know about oscilloscopes in unit 1?

Reply 35

Streebee2

Original post by GrandMasti

How much do we need to know about oscilloscopes in unit 1?

Quite a detailed amount, I'd say, as six mark questions involving them has come up before (June 2012 comes to mind).

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Reply 36

boyyo

for questions on suvat, can you use s= 0.5(U+V)t when they are talking about an object moving horizontally? thanks :smile:

Reply 37

crashMATHS

Original post by boyyo

for questions on suvat, can you use s= 0.5(U+V)t when they are talking about an object moving horizontally? thanks :smile:

If the object is accelerating at a constant acceleration, then of course.

If there is no acceleration, that equation simply becomes displacement = velocity x time.

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Reply 38

boyyo

Original post by kingaaran

If the object is accelerating at a constant acceleration, then of course.

If there is no acceleration, that equation simply becomes displacement = velocity x time.

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Thanks for clarifying that :smile:

Reply 39