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

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Original post by L'Evil Fish
I just did that one, lost a mark there... Not sure why


That question also confused me for a while, but it's because the question states that the current through the circuit is constant.
Original post by sagar448
Oh I see, but then when would it be exponential?


when the current is not kept constant by the use of a variable resistor. usually current, charge and voltage decrease exponentially.
How do i convert 4 x 10^4 Vcm^-1 to V m^-1, explanation/ exaples too for understanding please; thanks.

Sorry solved.

1/1cm

Then it follows, 1 / 1x 10^-2 = 100 m
(edited 8 years ago)
Original post by Oraeng
So why is it wrong if you do convert them if the units cancel out anyway?

It isn't

You probably converted them wrong
Original post by FeelsToWaltz
That question also confused me for a while, but it's because the question states that the current through the circuit is constant.


Yeah makes sense now
Original post by boristeve
when the current is not kept constant by the use of a variable resistor. usually current, charge and voltage decrease exponentially.


Oh I see, but current decreases exponentially when charging and voltage and charge increase exponentially. Just to make sure you don't mess up. :biggrin:
Reply 665
Original post by L'Evil Fish
It isn't

You probably converted them wrong



1.7cm = 0.017m
6.5cm^-1 = 0.065m^-1

am I missing something?
Hello does anyone know where to get the answers for the end of chapter questions in the OCR textbook?:redface:
Why they're not in here Idk:hmmm:

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Original post by Oraeng
1.7cm = 0.017m
6.5cm^-1 = 0.065m^-1

am I missing something?


Yeah the 6.5cm^-1 would go to 650
Original post by Leechayy
Hello does anyone know where to get the answers for the end of chapter questions in the OCR textbook?:redface:
Why they're not in here Idk:hmmm:

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these ones? sorry its a txt file, the pdf was massive and too big :s-smilie:
Can anyone explain the shape of the graph for question 4bii) please from the paper below

http://www.ocr.org.uk/Images/81115-unit-g485-fields-particles-and-frontiers-of-physics-specimen.pdf

Thanks.
Original post by boristeve
these ones? sorry its a txt file, the pdf was massive and too big :s-smilie:


It's okay
Thankss:tongue:

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Original post by boristeve
is it sinuisoidal?


No, it only consists of straight lines. The emf is zero before the coil enters the field, and then whilst in the field the emf stays constant (constant change of flux). The bit I don't get is that it says on the mark scheme that there should be a negative emf (the emf apparently changes direction half way through the motion) But the direction in which the flux is cut is always the same, so I don't get that?
Original post by ReeceG46
No, it only consists of straight lines. The emf is zero before the coil enters the field, and then whilst in the field the emf stays constant (constant change of flux). The bit I don't get is that it says on the mark scheme that there should be a negative emf (the emf apparently changes direction half way through the motion) But the direction in which the flux is cut is always the same, so I don't get that?


I think it is to do with Lenz's Law.
Hey everyone. New to the thread. Just curious: is anyone else, in a sick and twisted way, looking forward to this exam?
Original post by The Room Student
Hey everyone. New to the thread. Just curious: is anyone else, in a sick and twisted way, looking forward to this exam?


Lol no:mmm::mmm::mmm:


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Original post by boristeve
these ones? sorry its a txt file, the pdf was massive and too big :s-smilie:


Actually is it possible to just link it instead? I didn't think it'd be that bad :tongue:

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Can someone please help me with jan 2013 3d. Thanks.
Original post by Leechayy
Lol no:mmm::mmm::mmm:


Haha, sounds weird I know, but the low grade boundaries just make me feel kinda chilled about it! :biggrin:

There's a load of stuff to learn, but once you've grasped it, most questions are quite friendly I think...
Original post by The Room Student
Hey everyone. New to the thread. Just curious: is anyone else, in a sick and twisted way, looking forward to this exam?


Yes !!!
Original post by Leechayy
Actually is it possible to just link it instead? I didn't think it'd be that bad :tongue:

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here you go

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