OCR PHYSICS B G495~ 18th June 2015 AM ~ A2 Physics

Original post by Minecraft27

I got N to be 2.4x10^9 or something.

Anyone else get a resolution of 5.2x10^-7 and 30,000 lenses covering the eye?

I got something like that

Something like that

Umm....maybe a bit less? I can't remember though....it was a large number any way

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Reply 242

For one of the 1 mark motor question did anyone do BAN to find flux linkage?

Reply 243

Original post by STATER

For one of the 1 mark motor question did anyone do BAN to find flux linkage?

I did BA....
Then BAN/0.2 at the top of the next page
Bugger

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(edited 8 years ago)

Reply 244

Original post by Aeglor

I got about 22000, did it assuming there were 36 lenses per square 100m^-6... might have been more if you used a circle. Got the same resolution.

I got 30,000 by doing it the LONG way, with pi-r-squared and all, using the resolution that I got in the previous question, counting the eyes in the picture etc. After about a 500-step calc for 2 marks, I got 30000.

Reply 245

Rhetorical Hips

Low grade boundaries by the sounds of things then

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Reply 246

What exactly were they asking for in question 3 (the one about fields that had a straight line graph)?
I said the field was uniform shown by the straight line through the origin, and did two calculations which ended up as 4.2x10^3 and 4.3x10^3. Really was unsure what to do tbh.

Reply 247

Original post by falconinni

Those first two numbers ring a bell, i definitely got something x10^9 for N. That many air particles seems a lot though for a 'vacuum.'

Considering 1 mole of gas would be 6x10^23, one billion molecules per cubic centimetre is next to nothing.

Reply 248

Original post by Rhetorical Hips

Low grade boundaries by the sounds of things then

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Was the first one BA or BAN?
For the first one

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Reply 249

Rhetorical Hips

Guys, there are 100 x 100 x 100 centimetres cubes in one metre cubed right?

Somehow I screwed it up by saying there were 100 x 100 centimetres cubed in one metre cubed 😕

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Reply 250

Original post by STATER

I wrote V and m were directly proportional therefore it was uniform etc.

Reply 251

Original post by Minecraft27

I wrote V and m were directly proportional therefore it was uniform etc.

Yes son. Did you your constant come out the same though?

Any unofficial ms?

Original post by Rhetorical Hips

Guys, there are 100 x 100 x 100 centimetres cubes in one metre cubed right?

Somehow I screwed it up by saying there were 100 x 100 centimetres cubed in one metre cubed 😕

Posted from TSR Mobile

Yes, it was 100 x 100 x 100.

For the 4-marker about the rotor jamming, I wrote about resistance and stuff like that, filled the page with BS. Hope to get at least 2 for trying.

This paper was not too difficult. I reckon about 72 for an A.

Reply 254

rohanpritchard

Don't remember the question, something to do with a rotor in a stator where something increases (might have been potential difference but I'm not sure). It asks what happens to the speed of rotations? I put that although the force on the rotor will increase, the speed of rotations does not due to the fact that the question stated that the current remains the same and I figured this meant that the poles don't switch any quicker so it can't spin any faster... Does anyone agree/disagree? And does anyone actually remember the question properly? :smile:

Reply 255

Original post by Minecraft27

This paper was not too difficult. I reckon about 72 for an A.

Last year it was 74 though. Do you think this one was harder overall?

Reply 256

I got C for question 5 about the amps and voltage of the second coil (0.36A, 6V).

Anyone else get 16.8 for magnification and 11.2 Dioptres? My friend got 188 dioptres... which one is correct?

Reply 257

POLL
http://www.thestudentroom.co.uk/showthread.php?t=3411579

Reply 258

Original post by Minecraft27

I got C for question 5 about the amps and voltage of the second coil (0.36A, 6V).

Anyone else get 16.8 for magnification and 11.2 Dioptres? My friend got 188 dioptres... which one is correct?

Yes
Yes
I got x200 too

Reply 259