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# OCR B Physics H157/01 Fnd in Physics 24th May 2016 watch

1. (Original post by maryamkhawaja)
12.5 ohms for what?
The resistance of the fixed resistor
2. Yep 5600 and 3200 is right.

For the diodes, they only conduct one way above their forward bias voltage (0.4V, when the graph starts to go up) so by the time you reach 0.6V it's got a much lower resistance than the ammeter so most of the current flows through the diode.

When finding the wavelength of the electrons, did anyone actually get 0.7nm? Everyone I spoke to got 0.3-0.4 (I got exactly 0.35nm, exactly half!). What's up with that?
3. (Original post by otah007)
Yep 5600 and 3200 is right.

For the diodes, they only conduct one way above their forward bias voltage (0.4V, when the graph starts to go up) so by the time you reach 0.6V it's got a much lower resistance than the ammeter so most of the current flows through the diode.

When finding the wavelength of the electrons, did anyone actually get 0.7nm? Everyone I spoke to got 0.3-0.4 (I got exactly 0.35nm, exactly half!). What's up with that?
I got exactly half aswell so I just doubled the length of the wavelength measured in the picture to get 0.68x10^-9 which is pretty close
4. (Original post by Watevaidc)
I got exactly half aswell so I just doubled the length of the wavelength measured in the picture to get 0.68x10^-9 which is pretty close
I was going to say 'wavelength = double peak-to-peak so wavelength=0.7nm' but I knew that wasn't true and thought I might be docked a mark :/
5. (Original post by Watevaidc)
I got exactly half aswell so I just doubled the length of the wavelength measured in the picture to get 0.68x10^-9 which is pretty close
I also did this.
6. (Original post by Watevaidc)
The resistance of the fixed resistor
I gave the new spec OCR A. Is this the same paper?
7. (Original post by maryamkhawaja)
I gave the new spec OCR A. Is this the same paper?
This paper was OCR B Physics H157/01
8. (Original post by Watevaidc)
This paper was OCR B Physics H157/01
whats the difference? The questions are similar...
9. (Original post by otah007)
Yep 5600 and 3200 is right.

For the diodes, they only conduct one way above their forward bias voltage (0.4V, when the graph starts to go up) so by the time you reach 0.6V it's got a much lower resistance than the ammeter so most of the current flows through the diode.

When finding the wavelength of the electrons, did anyone actually get 0.7nm? Everyone I spoke to got 0.3-0.4 (I got exactly 0.35nm, exactly half!). What's up with that?
I wrote pretty much the same thing for the diodes with calculations but i didnt say that the current only flows in one direction. How many marks do you reckon i would get?
10. (Original post by maryamkhawaja)
whats the difference? The questions are similar...
The questions may be similar but they are not the same paper. The spec is different for a start and they are called different things.
11. I found it much harder than the sample and specimen paper. Not what I expect.
12. What did people put for the estimating questions on weight ect.
13. what did people put for the last question? How would you calculate the terminal velocity with the first method?
14. (Original post by swagmister)
What did people put for the estimating questions on weight ect.
I put 2N but I think it should be 1N
15. Hey what did everyone get for that question where you had to estimate the amount of bits used in the signal with the graph? i put 5 bits, is that right?
16. (Original post by JZ0120)
I put 2N but I think it should be 1N
I legit guessed and wrote 0.49N those questions were weird, at least they were only one markers
17. (Original post by swagmister)
I legit guessed and wrote 0.49N those questions were weird, at least they were only one markers
I think I got all estimations wrong
I found this is a harder paper than SAM and specimen. I would possibly failed.
What did you got for the terminal velocity? As the acceleration is not constant how could we calculate it? All the suvat equations assume acceleration is constant.
What I have done was just to divide distance by time( can't think anything else)
18. (Original post by JZ0120)
I think I got all estimations wrong
I found this is a harder paper than SAM and specimen. I would possibly failed.
What did you got for the terminal velocity? As the acceleration is not constant how could we calculate it? All the suvat equations assume acceleration is constant.
What I have done was just to divide distance by time( can't think anything else)
I thought the acceleration was constant as 9.8 I can't remember what I got but I used s =0.5(u+v)t
I thought was alright but everyone's saying it was hard so I've either done really well or really badly 😕, dividing distance by time is when there's no acceleration
19. (Original post by swagmister)
I thought the acceleration was constant as 9.8 I can't remember what I got but I used s =0.5(u+v)t
I thought was alright but everyone's saying it was hard so I've either done really well or really badly 😕, dividing distance by time is when there's no acceleration
Well I think I definitely get this wrong.
I thought the acceleration was not constant due to the air resistant and it is decreasing to 0 as terminal velocity reached.
20. Worst physics paper I've seen! Awful

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