x Turn on thread page Beta
 You are Here: Home >< Physics

# OCR PHYSICS B G491~ 19th May 2015 AM ~ AS Physics watch

1. (Original post by Zain.chishty)
The question said the atoms were less than 100 in the width so i used 99
Less than 100 could be 98, 97, 21, 87

Posted from TSR Mobile
2. (Original post by Mutleybm1996)
For resolution I just did image size/ magnification/ how many pixels

Not sure if that's right

Posted from TSR Mobile
no you have to use the actual distance represented by the image, not the one measured by a scale.
3. (Original post by Zain.chishty)
what did you get for the resolution of the image. was it 270 pm * 99 and than divided by 500
I didnt get * 99 i got * 50 because i measured each diameter as 1 mm and whole picture as 50 mm wide so 50 atoms which were 270pm diamter each then divided by 300 pixels, I think should be same answer but i used the height of the picture whereas you used the full width?? i dont remeber answer i got tbh but should be fine i think we used same method
4. (Original post by Zain.chishty)
no you have to use the actual distance represented by the image, not the one measured by a scale.
Yeah so Actual=image/magnification , then divide that by the number of pixels

Posted from TSR Mobile
5. (Original post by vish.handa)
I didnt get * 99 i got * 50 because i measured each diameter as 1 mm and whole picture as 50 mm wide so 50 atoms which were 270pm diamter each then divided by 300 pixels, I think should be same answer but i used the height of the picture whereas you used the full width?? i dont remeber answer i got tbh but should be fine i think we used same method
Should be a really small number any way

Posted from TSR Mobile
6. (Original post by jpetersgill)
Did u find the diameter of one atom?

Posted from TSR Mobile
It gave you it in the question i think, like 270 pm??
7. (Original post by vish.handa)
I didnt get * 99 i got * 50 because i measured each diameter as 1 mm and whole picture as 50 mm wide so 50 atoms which were 270pm diamter each then divided by 300 pixels, I think should be same answer but i used the height of the picture whereas you used the full width?? i dont remeber answer i got tbh but should be fine i think we used same method
Finally someone else who got diameter = 1mm

Posted from TSR Mobile
8. (Original post by Mutleybm1996)
Yeah so Actual=image/magnification , then divide that by the number of pixels

Posted from TSR Mobile
to find actual size you need magnification.
How would u find magnification ? image size/ actual size

and the question gives the diameter of one atom and says that in width the image has less than 100 atoms
so actual size = diameter of one atom * the total number of atoms
9. Peeps, is it still possible for me to get an A overall if I say get a C in this? By e.g getting 100 ums in unit 2?
10. (Original post by jpetersgill)
Finally someone else who got diameter = 1mm

Posted from TSR Mobile
It said measure it so i just used my ruler... what did others get?
11. (Original post by Zain.chishty)
to find actual size you need magnification.
How would u find magnification ? image size/ actual size

and the question gives the diameter of one atom and says that in width the image has less than 100 atoms
so actual size = diameter of one atom * the total number of atoms
Yes
But it didn't say HOW MANY atoms

Posted from TSR Mobile
12. (Original post by Mutleybm1996)
Should be a really small number any way

Posted from TSR Mobile
i measured the diameter as 0.8cm from the image then did 0.8cm/270pm
13. (Original post by vish.handa)
It said measure it so i just used my ruler... what did others get?
So did I but if you count the spaces between the bright spots you get 2mm (which many did) whereas you and I just measured the bright spots' diameters

Posted from TSR Mobile
14. (Original post by Mutleybm1996)
Yes
But it didn't say HOW MANY atoms

Posted from TSR Mobile
the way the question was set up , saying less than 100 atoms , it implied as if one less than a 100
15. (Original post by vish.handa)
It said measure it so i just used my ruler... what did others get?
i got it as about 0.8cm as there was a faint circle surrounding the white dot which represents the atm, so that was 0.8cm
16. (Original post by Zain.chishty)
the way the question was set up , saying less than 100 atoms , it implied as if one less than a 100
If it wanted you to use 99 it would have said 99...........

Posted from TSR Mobile
17. (Original post by HennersPD)
i measured the diameter as 0.8cm from the image then did 0.8cm/270pm
I didn't spot that
Might get some method marks for the formulae though

Posted from TSR Mobile
18. (Original post by jpetersgill)
So did I but if you count the spaces between the bright spots you get 2mm (which many did) whereas you and I just measured the bright spots' diameters

Posted from TSR Mobile
I'm not sure measuring it was the right way to go to be honest especially if it's that ambiguous

Posted from TSR Mobile
19. (Original post by jpetersgill)
So did I but if you count the spaces between the bright spots you get 2mm (which many did) whereas you and I just measured the bright spots' diameters

Posted from TSR Mobile
Ah right fair enough yeah i did the diamter of the dots too but whoever is wrong , there will proably be a mark for allow 2mm or something
20. (Original post by HennersPD)
i got it as about 0.8cm as there was a faint circle surrounding the white dot which represents the atm, so that was 0.8cm
0.8cm as in 8 mm??? that seems quite large or do you mean 0.8mm? if so i got 1mm which is close to that ?

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: June 8, 2015
Today on TSR

### How do I turn down a guy in a club?

What should I do?

### My dad said he's stalked me at uni!

Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE