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AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

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Ah ok lets see, I set June 2013 in the UMS converter and got:

Unit 1: 88
Unit 2: 106
Unit 3T: 39
Unit 4: 108
Unit 6T: 17
Unit 5A: ?

Total UMS marks yet (predicted of course): 358
When I added all the needed UMS for an A grade in June 2013, it was 480
So the difference is 122 UMS.
Looks like I won't probably land an A looking at that :/

What is total UMS acheivable and it seems like you really messed up 6T :l

scratch that..

you could get an A* if you haven't actually messed up 6T.

(edited 8 years ago)

Reply 1461

QueNNch

Original post by betbi3etwerrd

What is total UMS acheivable and it seems like you really messed up 6T :l

Total UMS achievable is 120 + 120 + 60 + 120 + 120 + 60 = 600
and yeah in 6T I got 33 out of 50 :frown:

Now I used the UMS converter for June 2014 and it says I need 52 UMS in Unit 5A!

Woah the difference is so huge...
According to June 2013 I need 122 UMS
According to June 2014 I need 52 UMS

(edited 8 years ago)

Reply 1462

betbi3etwerrd

Original post by QueNNch

Total UMS achievable is 120 + 120 + 60 + 120 + 120 + 60 = 600
and yeah in 6T I got 33 out of 50 :frown:

Now I used the UMS converter for June 2014 and it says I need 52 UMS in Unit 5A!

Woah the difference is so huge...
According to June 2013 I need 122 UMS
According to June 2014 I need 52 UMS

I do 6x instead and I feel it is far easier to get an A* because you only need around 38/55 to get the A*! (in 6x)

Reply 1463

Sbarron

Just found this which might help people with an idea. Sorry if you can't make sense of it as it's been scribbled all over but it shows ums/raw conversions and %

Reply 1464

Specter

Original post by gcsestuff

For turning points yes.

It's how between two plates an electron can act like a wave and jump across. As long as the gap is small enough and the potential difference is large enough. This is how electron tunnelling microscopes work.

Posted from TSR Mobile

Hmmm I meant for the topic of binding energy? Its in the textbook but seems so confusing :s-smilie:

Reply 1465

QueNNch

Original post by Sbarron

Just found this which might help people with an idea. Sorry if you can't make sense of it as it's been scribbled all over but it shows ums/raw conversions and %

Thanks for that I used it and it still looks like I need ~120 UMS for an A minimum :\
Did not know that the coursework could make so much difference :frown:

Fingers crossed for lower grade boundaries compared to June 2013 and I can get an A...

What did you get for yours?

Reply 1466

CD223

Original post by Specter

Hmmm I meant for the topic of binding energy? Its in the textbook but seems so confusing :s-smilie:

What does the book say? We learnt very briefly. Just that an alpha particle uses the release of binding energy to overcome the Coulomb barrier and therefore gains kinetic energy and leaves the nucleus?

Posted from TSR Mobile

Reply 1467

slaven123

Is a Quasar the name for a galaxy with a black hole in the centre, or the name for a black hole in the centre of a galaxy? If you get what I mean.

Reply 1468

Absent Agent

Original post by Specter

Hmmm I meant for the topic of binding energy? Its in the textbook but seems so confusing :s-smilie:

The textbook doesn't even know what it's saying. In that they try to simplify what isn't an elementary concept.

Posted from TSR Mobile

Reply 1469

BoigaDendrophila

are there any past papers from before 2007? The link on the first page just has 2007 onwards.

Reply 1470

AR_95

Someone give me a concise definition of the metastable state?

Reply 1471

Sbarron

Original post by QueNNch

Thanks for that I used it and it still looks like I need ~120 UMS for an A minimum :\
Did not know that the coursework could make so much difference :frown:

Fingers crossed for lower grade boundaries compared to June 2013 and I can get an A...

What did you get for yours?

I haven't done too well (messed up with stupid things) the unit 6 written part was AWFUL for me and I made some really really stupid mistakes on unit 4 too. I need a B overall but must get 101 UCAS points according to this on unit 5 now! I'm studying for hours ATM!! I'm desperate!! Lol

Reply 1472

Sbarron

Original post by Mehrdad jafari

The textbook doesn't even know what it's saying. In that they try to simplify what isn't an elementary concept.

Posted from TSR Mobile

I think I've learned it now although I'm far from full comprehension of it

Reply 1473

PotterPhysics

Turning points chapter 1: "The emission of light from a discharge tube happens because the voltage applied to the tube is so high that it pulls electrons out of some of the gas atoms in the tube."

How can a high voltage (edit: by itself) pull off electrons from atoms?

(edited 8 years ago)

Reply 1474

betbi3etwerrd

Original post by slaven123

Is a Quasar the name for a galaxy with a black hole in the centre, or the name for a black hole in the centre of a galaxy? If you get what I mean.

Quasars are the most distant and most powerful observable objects.
Using inverse square law it is shown that they produce the same power output of several galaxies but variation in their output suggests they may be only the size of a solar system.
They are now believed to come from a super massive black holes at the centre of active galaxies.

They emit electromagnetic radiation from the whole spectrum.

Reply 1475

PotterPhysics

Original post by Sbarron

I think I've learned it now although I'm far from full comprehension of it

Hello what exactly do you need help with I might be able to help

Reply 1476

Protoxylic

Original post by AR_95

Someone give me a concise definition of the metastable state?

A species, formed via beta decay of a parent nucleus, that is formed in an excited state and stays in this state for a prolonged period of time

Reply 1477

PotterPhysics

This is all slightly confusing: If thermionic emission isn't used in a gas discharge tube where do the electrons come from? I am aware that they come from the cathode and some are apparently pulled off gas atoms by the high voltage. Where do the cathode ones come from and how does the "pulling off by high voltage" mechanism work. (It seems unlikely that a high voltage by itself can cause atoms to ionize but I could be wrong.)

Reply 1478

AR_95

Original post by Protoxylic

A species, formed via beta decay of a parent nucleus, that is formed in an excited state and stays in this state for a prolonged period of time

So I understand that there's a time delay before the daughter nucleus emits the gamma photon
The metastate, is when the daughter nucelus is excited and is yet to emit the photon to de excite/ return to ground state?

Also in my book it mentions this occurs in alpha decay, so why've you only limited it to Beta?

Original post by PotterPhysics

The high voltage , or higher potential difference, means that the acceleration of particles is also higher. Higher acceleration means higher force (F=ma) and also velocity so the collision is more likely to cause ionisation