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# OCR Physics B G491 20th May 2013 watch

1. (Original post by King Hotpie)
What did people get for the 'estimate the factor that the intensity has increased' or something like that, the logarithmic scale thing for the dolphin click question. I put 10^7, then crossed it out and changed to 10^6.7
I got 90 - 60 = 30db

the sound level increases by a factor of 10 for every 10db increase

therefore 30/10 = 3

103 = 1000

so its 1000x larger
2. (Original post by King Hotpie)
What did people get for the 'estimate the factor that the intensity has increased' or something like that, the logarithmic scale thing for the dolphin click question. I put 10^7, then crossed it out and changed to 10^6.7
I initially also put 10^7 but then looked at the y axis then decided to put 10
3. (Original post by dannyboy819)
I got 90 - 60 = 30db

the sound level increases by a factor of 10 for every 10db increase

therefore 30/10 = 3

103 = 1000

so its 1000x larger
Why 90-60? Did I miss something?
4. (Original post by King Hotpie)
Why 90-60? Did I miss something?
I think it said what factor does the sound level increase by from one frequency to another (owtte)...

...which worked out to give 90db and 60db

TBH I can't really remember.

Does anyone have a copy of the paper?
5. (Original post by King Hotpie)
What did people get for the 'estimate the factor that the intensity has increased' or something like that, the logarithmic scale thing for the dolphin click question. I put 10^7, then crossed it out and changed to 10^6.7
(10^9) / (10^6) so 1,000
6. For the number of levels question i did log (base 2) 400 = 8.6 - but i stupidly rounded it down to 8. Do you think they'll give me the mark (in some past papers they do say "accept 8" when the real answer is 9)?
7. (Original post by King Hotpie)
Why 90-60? Did I miss something?
Because the dB level increased from 60-90, so you needed to calculate the difference
8. (Original post by Josh-B)
Because the dB level increased from 60-90, so you needed to calculate the difference
...........................

Damn it
9. I thought it just said for the frequency at 20kHz? Does anyone have a copy of the paper they can kindly upload?
10. (Original post by marksmith34)
What did everyone put for the ebook question - first time I've ever seen a social/ethical question in a physics paper...
I put -
Advantage: Implementing books in modern technology may encourage younger people to read more.
Disadvantage: Research has shown that reading on a screen is much harder on the eyes than reading off a page, so people may develop eyesight problems if they read off of the ebook too much.

And yeah I don't know of any research for the disadvantage, but it's the weirdest question I have ever seen.
11. I hate this unit so much. Other than the wave equation, was for really a single 'proper' physics question? The rest all seemed more like computer/material science

And estimating the average number of pages in a book. REALLY?
12. (Original post by King Hotpie)
I hate this unit so much. Other than the wave equation, was for really a single 'proper' physics question? The rest all seemed more like computer/material science

And estimating the average number of pages in a book. REALLY?
I thought there was some sort of formula that I wasnt getting from the text and so just left the answer blank. It was only when I got outside when my friends told me that you just had to estimate *facepalm*
13. Would they give a mark for just 90-60
14. Failed

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15. i thought the paper was quite difficult, easy to drop silly marks. It was definitely different to past papers. Does any one have the paper to upload? Would be nice to see how much things are worth and then we can see how we did!

if i am honest.... i cant wait to drop the f***er!
16. (Original post by Dan1300)
i put 10^7
Why did you get 10^7?
17. Cant really remember now i just remember 20 to 90 so the difference is 70.
As it increases by 10 times each time it increases by 10^7 overall
18. (Original post by benewen)
I got 30mS because conductance in parrallel add together. The 30mS conductance at the top was in series.
However there was 30 mS and conductance in series is 1/G total = 1/30 + 1/30 therefore 15 mS

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19. (Original post by Dan1300)
Cant really remember now i just remember 20 to 90 so the difference is 70.
As it increases by 10 times each time it increases by 10^7 overall
Oh ok.... I said that it went up by 3 intervals 60-70db 70-80db and 80-90db so it goes up by 10^3 times so 1000
20. (Original post by jehearo)
However there was 30 mS and conductance in series is 1/G total = 1/30 + 1/30 therefore 15 mS

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Yeah i got the same! For the question above the last one, did you put stress=Force/cross sectional area so therefore more cross sectionalleads to a smaller stress (i think it was 5 correct me if i am wrong) so therefore if you had 1nm of force it would be 1/1 and 1/5 so therefore 1/5 more?

Sorry if that makes little sense!

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