OCR Physics G485 - June 2013 Unit 5 (OFFICIAL THREAD)

OP

Original post by browb003

You can copy this link, it should take you to the first post of mine :smile:

http://www.thestudentroom.co.uk/showthread.php?t=2244676&page=9&p=42286271#post42286271

I'd think so definitely, booklets like these have served me incredibly well. I go through similar ones for all of my a levels and honestly, the exams are pretty much already done when you sit down. It's just a case of writing then.

For example; in the Jan 2013 paper there was a question asking Why can fusion in stars occur at temperatures lower than the predicted temperature of around 9 million Kelvin? (something like that)

And I had already seen a question in the legacy pack for nuclear physics, so I didn't even need to think about it (it was only 1 mark and I still put down 2 answers because I was pretty cocky, I do confess haha :tongue:

)

If you want the answer:

Spoiler

Beast ! And what would you recommend for Unit 4 then?

I will go to school and print all of those Legacy Papers off haha!!

You are an animal. So glad I made this thread. Really glad we've got some quality people here. It's really motivating me.

Reply 181

Original post by Better

Beast ! And what would you recommend for Unit 4 then?

By Unit 4 do you mean Newtonian World or the Medical Physics part of Fields, Particles or Frontiers?

And that's alright :smile:

I hope you do well!

Posted from TSR Mobile

Reply 182

OP

Original post by browb003

By Unit 4 do you mean Newtonian World or the Medical Physics part of Fields, Particles or Frontiers?

And that's alright :smile:

I hope you do well!

Posted from TSR Mobile

Newtonian World?

Reply 183

Original post by Better

Newtonian World?

I have legacy booklets for those too, I think they're in the thread for the January 2013 for Newtonian World. If you want, I'll upload them tomorrow (I'm too tired at the moment) I'll set a reminder for it

Posted from TSR Mobile

Reply 184

OP

Original post by browb003

I have legacy booklets for those too, I think they're in the thread for the January 2013 for Newtonian World. If you want, I'll upload them tomorrow (I'm too tired at the moment) I'll set a reminder for it

Posted from TSR Mobile

Thanks so much bro!

Reply 185

Gulzar

2

Does anyone know how much we need to know on fundamental particles. I really need to revise but the teacher has hardly done anyhting on it :frown:

Reply 186

101101

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Anyone have jan 2013 paper?

Reply 187

Rhodopsin94

Can anyone help me with this.

I have attached photos of the question to this post, and my attempt at a diagram for part a).

I'm aware that once I know the electrical force from part a), I can rearrange the equation for Coulomb's law to find the charge on the polystyrene, but I don't know how the diagram should be drawn. (If the angle of the thread should be subtended towards/away from the Van de Graaff machine or if I've missed anything)

I think the horizontal/vertical component of the thread and sphere could be used, but not sure how since gravitational and electrostatic forces are obviously different types.

Can someone tell/show me how the diagram should be drawn, and then how to calculate the electrical force?

Thanks in advance :smile:

By the way, the question starts at the bottom of one page, and continues at the top of the next. (The Van de Graaff and polystyrene sphere one to which I have referenced above)

(edited 11 years ago)

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Reply 188

Original post by Better

Thanks so much bro!

There you go http://www.thestudentroom.co.uk/showthread.php?t=2307470&p=42296138#post42296138
:smile:

Reply 189

i'm the daddy!

Original post by browb003

More

Fantastic work - legend!
questions 84 to 98 missing - presumably nuclear physics part 7 pdf ??

(edited 11 years ago)

Reply 190

Nuclear Physics_Part7 Part1.pdf593.8KB

Original post by i'm the daddy!

Fantastic work - legend!
questions 84 to 98 missing - presumably nuclear physics part 7 pdf ??

Damn you were right, even after splitting the original one up into separate booklets, it was too big to upload haha. Here you go

Nuclear Physics_Part7 Part2.pdf520.4KB

Reply 191

i'm the daddy!

Original post by browb003

Damn you were right, even after splitting the original one up into separate booklets, it was too big to upload haha. Here you go

fantastic! +ve rep

Reply 192

GeorgeL3

5

Original post by Rhodopsin94

Can anyone help me with this.

I have attached photos of the question to this post, and my attempt at a diagram for part a).

I'm aware that once I know the electrical force from part a), I can rearrange the equation for Coulomb's law to find the charge on the polystyrene, but I don't know how the diagram should be drawn. (If the angle of the thread should be subtended towards/away from the Van de Graaff machine or if I've missed anything)

I think the horizontal/vertical component of the thread and sphere could be used, but not sure how since gravitational and electrostatic forces are obviously different types.

Can someone tell/show me how the diagram should be drawn, and then how to calculate the electrical force?

Thanks in advance :smile:

By the way, the question starts at the bottom of one page, and continues at the top of the next. (The Van de Graaff and polystyrene sphere one to which I have referenced above)

Your diagram is pretty much the same as mine:
Charged Spheres TSR.png

Since only two vertical forces are the vertical component of Tension and weight and since the vertical forces are in equilibrium, we can say:
Tcos45 = 0.25 x 10^-6 x 9.81
There are also however, only two horizontal forces; the horizontal component of the tension and the electrical force. Therefore:
F = Tcos45
F = 2.4525 x 10^-6 N

Then you're right you can use Coulomb's law for the second part, I get an answer of q=-2.73 x 10^-9 C

Reply 193

Picture~Perfect

19

*Subcribes*
I'm re-taking this exam, it was my worst paper last year and if I can get a higher mark this year there is a chance I can up my overall grade from a B to an A :smile:

*fingers crossed*

Edit:
I've just seen that my pdf file is still here from last year, I hope it helps if so I'm wiling to make any other study materials but by the looks of it pretty much everything has been covered.

I'm also going to try my best to help with any questions, I'm still re-familiarising myself with the subject knowledge but I'll try my best to help, I find explaining things to others a great way to revise :smile:

(edited 11 years ago)

Reply 194

Picture~Perfect

19

Original post by Namod

Hello,
I started doing the questions in the OCR Physics A2 book (The main one for OCR) and got stuck in few questions:

Page 120, Q3a:
In the answers at the back it says "equally spaced horizontal parallel lines from plate to plate." How do they know that the Electric field from A to B is equal to the E Field from C to B?

An electric field between two parallel plates is uniform (therefore the field lines are equidistant) in this case I think A and C are the parallel plates.

Original post by Namod

Page 121, Q6c:
Can anyone please explain the question + the answer?

With this question I think what they are asking is how do you get the electron beam to move across the screen?
In order to do this you would need to change the magnetic field which can be done by changing the current in the coil as this has induced the magnetic field. Once the field is altered the electron beams deflection will be altered. They are then saying that if you reverse the field the deflection will be from up to down.

I'm not sure if that makes it any clearer...
Let me know if that helps at all.

Reply 195

blossomx

20

Hey.

Not sure if any of you will find these useful but I found a Youtube channel which has quite a few videos relevant to this unit. They're quite long and watching a piece of paper with writing on isn't the most entertaining way to learn but idk I think the way he explains things is great.

http://www.youtube.com/user/DrPhysicsA

Reply 196

Rhodopsin94

Original post by GeorgeL3

Your diagram is pretty much the same as mine:
Charged Spheres TSR.png

Since only two vertical forces are the vertical component of Tension and weight and since the vertical forces are in equilibrium, we can say:
Tcos45 = 0.25 x 10^-6 x 9.81
There are also however, only two horizontal forces; the horizontal component of the tension and the electrical force. Therefore:
F = Tcos45
F = 2.4525 x 10^-6 N

Then you're right you can use Coulomb's law for the second part, I get an answer of q=-2.73 x 10^-9 C

Great thanks, that helped to make sense of the stuff which I couldn't quite get the grasp of.

Reply 197

Lilmzbest

Original post by LeaX

Hey.

Not sure if any of you will find these useful but I found a Youtube channel which has quite a few videos relevant to this unit. They're quite long and watching a piece of paper with writing on isn't the most entertaining way to learn but idk I think the way he explains things is great.

http://www.youtube.com/user/DrPhysicsA

This is great, i learn really well by watching videos so thanks :smile:

Reply 198

OP

How much Detail do we have to go into on the details of MRI.

I don't want to learn more than I need to?

Reply 199