OCR Physics A G485 - Frontiers of Physics - 18th June 2015

thanks!
yeah cos my teacher said imagine there's a positive test charge between them and which is more neg or pos, so this and that so it kinda got a bit too complicated....
i understand now ^_^

I have a mock tomorrow for this unit on everything except medical imagining and nuclear physics :P
Did all the papers and stuff xD
Please watch over me guys >_<

So...how did it go?

got 1% off an A in the G485 mock we had before half term, so many silly mistakes dammit

OH MY GAH 1%!
But isnt UMS is more important then grade, so you got a very high UMS!
Which paper did you do, our paper was all muddled up with random questions from various papers so it is harder, as someone may memorise by accident the correct mark scheme...

Result out next week, tell you then but the boundaries are going to be 80% A and then so on.

Ours was the June 2014 paper. I could have had a peek before hand but I guess that just destroys the purpose IMO.

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Would you happen to have a copy which I can look xD
Cos I am very curious if it is somewhat similar to the past papers because seeing the unit 4 2014 paper and it was so much more harder like woah dude calm down.

I know man the G484 june 14 paper was crazy! OCR were like "hey look we've given you an extra 15 minutes" but little did we know they'd popped an extra question in there.

Yeah sure I'll attach some of the questions. Bearing in mind the A grade was 69/100 I'd say that was hard too, and a pretty harsh (IMO) mark scheme to go with it.

Loads of unintentional slip-ups, please try not to hurt yourself from excessive laughter?

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Where are you in terms of content.

For this module specifically I have nuclear physics and the space module per se left to revise over.

We're currently on the last topic of med (MRI; also in my opinion the toughest) and then we're onto space.

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lol, you just revise the mark scheme past questions of medical physics....


How long did it take you to get through nuclear?

Are you applying/applied to oxbridge

Could do, if you're not going for further study in physics I guess.

It took us about three weeks.

No, my firm choice is the university of Glasgow . Have you applied to oxbridge?

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ooh, were said shots fired :d

Ah right, that's not too bad.

Yeah Oxford. Ah nice, Physics?

How are you finding this module?

COD pun I see.

Yeah physics wbu? And the paper's don't seem too nice but for me G482 is a bit harder.

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1v1 me rust m9?

I played my fair share back in the day and by fair share - I mean all the tiem

Econ with management. The content this year looks so much better than AS.

Did you do the PAT, also are you doing further maths?

I like physics. Kind of wish I appreciated it more before.

Seen the last question on the g484 june 2014?

Good luck cod brah

Can someone explain to me what this means?

'Work is done against the repulsive force'

This is the answer to a question about Lenz's law, where the North Pole of a magnet is brought towards a solenoid
The question asks to state the polarity of the solenoid at this end and explain using ideas of energy conservation.
So the polarity is North, which I understand. But I don't understand why the above quoted sentence is the explanation in terms of energy conservation.

For the North Pole being brought back out again, the solenoid would become South at this end right? And so the energy explanation would be: work is done against at attractive force?

But can someone still explain how work being done against the force ensures the law of energy conservation is not violated?


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Think. Imagine what would happen if, when you moved the N pole of the magnet towards the solenoid, that end of the solenoid became a S pole as a result?
How would that relate to conservation of energy?

The magnet would experience a force towards the solenoid.
Ahh
That would induce more emf
So experiences more force etc etc
And that is creating energy and so violates the law of conservation of energy, right?

So the magnet must be North, so that work is done against the repulsive force and hence energy is conserved - is that correct?
Electromagnetic induction is the toughest topic I think.


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That's basically it.
If a S pole was induced, moving the magnet slightly towards the solenoid would cause it to be attracted, thus moving further and faster. This would generate energy from nowhere.
Yes em induction is a difficult topic. The number of questions asking for help on this topic here is what leads me that conclusion...