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# AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread] watch

1. Hello everyone!

I was wondering if anyone could help me on a question that I was stuck on.

Its is Q10 Jan '04 in the following link. I do not understand why C is the answer.
2. Thanks, so am i right in thinking that it would take longer for a magnet to pass through an incomplete coil than to free fall?

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3. (Original post by chughes17)
Thanks, so am i right in thinking that it would take longer for a magnet to pass through an incomplete coil than to free fall?

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No Because in an incomplete circuit there's no current induced hence there's no opposing (force)magnetic field to slow it down. So if it's a vertical fall acceleration will be just g
4. (Original post by Disney0702)
Hello everyone!

I was wondering if anyone could help me on a question that I was stuck on.

Its is Q10 Jan '04 in the following link. I do not understand why C is the answer.
Look on the data sheet - E = Q/4pier2, so doubling r quarters E. V=Q/4pier, so doubling r halves V.
5. (Original post by sykik)
No Because in an incomplete circuit there's no current induced hence there's no opposing (force)magnetic field to slow it down. So if it's a vertical fall acceleration will be just g
But there's still an emf induced, so what effect does that have?

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6. (Original post by Lau14)
Look on the data sheet - E = Q/4pier2, so doubling r quarters E. V=Q/4pier, so doubling r halves V.
Oh my! Its that simple!

Thank you so much!
7. My teacher told me that we'll be provided an extra answer sheet to write our answers down for Section A.

Does anyone knows what it looks like?

I do not want to find out on the very day I sit the exam.
8. (Original post by Disney0702)
My teacher told me that we'll be provided an extra answer sheet to write our answers down for Section A.

Does anyone knows what it looks like?

I do not want to find out on the very day I sit the exam.
Yes, we used one for our mock (if I find that I have the sheet when I'm at home tonight I'll take a photo and post it in the thread), but it has I think a details section at the top (name etc), numbers 1-50 (presumably for different papers)down the page with four dots next to them labelled A-D. You colour in the correct dot (in pen) to indicate your answer - any working etc do on the question paper (which does have the advantage of meaning you can write all over it!).
9. spec : energy considerations for an orbiting satellite?
10. (Original post by Lau14)
Yes, we used one for our mock (if I find that I have the sheet when I'm at home tonight I'll take a photo and post it in the thread), but it has I think a details section at the top (name etc), numbers 1-50 (presumably for different papers)down the page with four dots next to them labelled A-D. You colour in the correct dot (in pen) to indicate your answer - any working etc do on the question paper (which does have the advantage of meaning you can write all over it!).
Ah thanks a lot ☺ it'd be great if you could upload a picture, should you find it, because I don't think my teacher showed us.
11. (Original post by CD223)
• The ratios of gravitational field strength equals the ratio of the masses divided by the ratio of the radii squared.

• the mass is proportional to the product of the density times volume, and hence proportional to the density times radius cubed:

• The ratios of gravitational field strength equals the ratio of the densities multiplied by the ratio of the radii cubed divided by the ratio of the radii squared.

Cancelling top and bottom (cubed and squared terms):
• The ratios of gravitational field strength equals the ratio of the densities multiplied by the ratio of the radii.

• Dividing the ratios of gravitational field strength by the ratio of the densities gives 6 divided by 5/3 which is 3.6.

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Thanks, how did your c3 exam go

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12. (Original post by Disney0702)
Ah thanks a lot ☺ it'd be great if you could upload a picture, should you find it, because I don't think my teacher showed us.
Yeah an awful lot of people have never seen one or even knew they were a thing! I will do my best to find it tonight
13. (Original post by sykik)

Hi can anyone explain what should the angle be between. I came across a multiple choice question where they had given us a wrong angle and we had o workout the right one but i don't understand the angle should be between? Thanks
It is between the normal of the coil and the uniform magnetic field.

I hope that helps
14. Can anyone remind me how to work out Q13 in this paper?
http://filestore.aqa.org.uk/subjects...W-QP-JUN10.PDF
15. (Original post by Ilovemaths96)
spec : energy considerations for an orbiting satellite?
Guys?
16. (Original post by EmiratesCaptain)
Can anyone remind me how to work out Q13 in this paper?
http://filestore.aqa.org.uk/subjects...W-QP-JUN10.PDF
The ratio of the charge to the distance is the same for both charges. Namely; 4uC/d=16uC/(120mm-d)
You just need to rearrange this to find d.

Another way of looking at it is that the potential due to the 4uC charge at that point 'd' is equal and opposite (in sign) to the potential due to the 16uC charge. So 4uC/d + -16uC/(120mm-d) = 0 And rearrange to find d.
17. (Original post by Disney0702)
It is between the normal of the coil and the uniform magnetic field.

I hope that helps
Yh but that's just one magnetic field line... There's another one you can make an angle with so do u use the first nearest line to the normal?
18. (Original post by SuperMushroom)
Thanks, how did your c3 exam go

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C3 went really well - thanks for asking I posted an unofficial mark scheme and most people seemed to agree so I'm happy - just need to replicate that in Core 4!

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19. (Original post by Ilovemaths96)
Guys?
Well, if the spec says energy considerations then it depends on the conditions of the satellite. For example if the radius of the orbit decreases what energy changes take place. Not sure really

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20. Anyone likely to be able to take home with them a MC copy of this year's paper after the exam so we can discuss answers? Or is that too illegal?:L

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