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# Official OCR New Spec AS Level Physics: Depth in physics - 9th of May watch

1. I forgot to factor in the x10^-3 for the gradient and the resisitivity
2. For the breaking stress i talked about measuring stress and strain and when the wire broke i would read off the stress/streain graph to find a value for breaking stress. Bc breaking stress is just force over area. Is this right
3. (Original post by voltz)
I belive I got 5.6 x 10^3, and 0.100 for the bit about finding the resistivity...? Did you get something similar for that?
yeah I think I got something like 0.1045 ohm metres.
4. (Original post by sen99)
For the breaking stress i talked about measuring stress and strain and when the wire broke i would read off the stress/streain graph to find a value for breaking stress. Bc breaking stress is just force over area. Is this right
Yeah; I don't think you have to include the strain bit because it was only about the breaking stress. I just said use the pulley system one; and then measure the diameter multiple times with a micrometer; take an average and use A=πd^2/4 for the cross sectional area; and then do the same for the mass x 9.81 where the wire began to neck/ about to break and do this multiple times and take an average. Then do F/A=breaking stress.
5. (Original post by Parhomus)
Threshold frequency; so it showed that it was a particle as there is no way of explaining this phenomena with the wave like nature of EM radiation. Also explained it talking about how if it was explainable using the wavelike nature then continuous energy stored would eventually lead to electron emission and so the leaf would fall, but obviously it didn't. Also talked about how the intensity doesn't affect the time taken for the radiation below the threshold frequency showing the previous contradiction. Then I said that the fact that the leaf falls faster when intensity increases for uv shows the particulate nature as it means there are more photons per m^2 and so more photons for the one-to-one ratio >>>electrons escape faster so it falls faster.
I also said that for white light the violet end of the spectrum could have enough energy to cause electron emission bc there gold leaf still fell really slowly. Is his right.
6. (Original post by sen99)
I also said that for white light the violet end of the spectrum could have enough energy to cause electron emission bc there gold leaf still fell really slowly. Is his right.
Yeah, I didn't bother writing that but it's probably correct; maybe I'll lose a mark for that? I just thought that the main gist of it was what i wrote though.
7. (Original post by voltz)
I belive I got 5.6 x 10^3, and 0.100 for the bit about finding the resistivity...? Did you get something similar for that?
i got 0.112
8. I got 8% for uncertainty because x2 for l^2 and then x2 for measuring at the top and bottom of the ruler.
9. (Original post by BobAhmed)
i got 0.112
There will probably be error carried forward and the difference will just be because our different gradients - atleast the answers for that seem to be very similar
11. Unoffical markscheme anyone?
12. (Original post by voltz)
I belive I got 5.6 x 10^3, and 0.100 for the bit about finding the resistivity...? Did you get something similar for that?
I got this.
I got 5800 for the gradient and 0.11 for the resistivity.
For the gradient, were we meant to write it in standard form on the answer line?

Are these roughly the correct answers?
13. I found the gradient to be 5.8x10^3, 10^-3 on X axis so included that when finding answer
14. I got 0.8% for the uncertainty one...
15. (Original post by Turtlebunny)
I got this.
I got 5800 for the gradient and 0.11 for the resistivity.
For the gradient, were we meant to write it in standard form on the answer line?

Are these roughly the correct answers?
Yeah I got pretty much the same
16. Can't wait until this unofficial mark scheme goes up
17. (Original post by Parhomus)
Yeah; I don't think you have to include the strain bit because it was only about the breaking stress. I just said use the pulley system one; and then measure the diameter multiple times with a micrometer; take an average and use A=πd^2/4 for the cross sectional area; and then do the same for the mass x 9.81 where the wire began to neck/ about to break and do this multiple times and take an average. Then do F/A=breaking stress.
18. what did people get for the max ke question? Me and few others in class got 1.24x10^-19 if I remember rightly
19. (Original post by maryamkhawaja)
6 for the breaking strain (but it was a QWC one)
20. These grade boundaries are going to be inflated...

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