OCR Physics A - G485: Fields, Particles & Frontiers of Physics - June 2012

whats the answer for what is an absorption spectrum?
if i described how it shows either red **** or blue shift is that not atleast a mark

Reply 1381

stunnaman

Please ocr make it 66 to get an a (or less) !!

Reply 1382

SomeoneIveNeverMet

Original post by jamesvernon

The fact it said state your reasoning made me think i was right.

I reasoned that all the mass of the positron + electron gets converted to energy. Use Einstein's equation. DIVIDE BY 2, then the lambda, h and c equation from unit 2 and Bob's your uncle.

At least i think so :P

Yup this is all correct (except that Bob isn't my uncle :tongue:

)
For my reason I wrote that each electron/positron (beta particle) produces one gamma photon (although I may have said ray :/) I probably won't get a mark for the explanation. But yes your math is correct :smile:

Reply 1383

tallen90

3

Original post by SomeoneIveNeverMet

I used the gradient of the graph at it's steepest point and got about 11.6V..which to 2s.f. is 12. (did this because emf = - rate of change of manetic flux linkage)

..is that how you got the Emf?

Weird, I did it and got exactly 12V. I guess there's different ways of doing it. I know my calculation was something like 1.2x10^-2/1x10^-3.

Reply 1384

SomeoneIveNeverMet

Original post by tallen90

Weird, I did it and got exactly 12V. I guess there's different ways of doing it. I know my calculation was something like 1.2x10^-2/1x10^-3.

I guess it depends on your gradient. I didn't draw a tangent though, which I now know I should have :/ oh well

Reply 1385

jamesvernon

Original post by tallen90

Weird, I did it and got exactly 12V. I guess there's different ways of doing it. I know my calculation was something like 1.2x10^-2/1x10^-3.

I said something along the lines of...

Since emf = change in flux over time, the graph of EMF is the differential of the flux graph. Hence the max occurs at the point on the graph where whatever time it was it occured.

Took a small interval, = 12v exactly.

Reply 1386

Small123

15

Original post by tallen90

Weird, I did it and got exactly 12V. I guess there's different ways of doing it. I know my calculation was something like 1.2x10^-2/1x10^-3.

Was it something like

\dfrac{(0.6--0.6) \times 10^{-2}}{(3-2) \times 10^{-3}}

? That's how I did it and got exactly 12V

Reply 1387

Toshiya

1

Original post by tallen90

Weird, I did it and got exactly 12V. I guess there's different ways of doing it. I know my calculation was something like 1.2x10^-2/1x10^-3.

This is how I did it too. I kept getting 8V at first the other way I did it, then it just clicked.

Reply 1388

shiinkii

8

Im so bombed right now. I worked my butt off for that paper. I mean literally. I revised so hard for so long that the chair I was sitting on became anti matter to my butt and they annihilated each other in order to produce countless amounts of gamma photons in opposite directions. Perfectly obeying the law AE=AMC^2 (A representing delta). I currently no longer have a butt.

Reply 1389

RESIDUAL FLUX

what did u you guys get for the gradient on the first page, i got gyrometric ratio as the quantity

Reply 1390

RESIDUAL FLUX

but my freind said it was capacitance but how?? cause isnt capacitance charge/voltage??

Reply 1391

RESIDUAL FLUX

Original post by shiinkii

Im so bombed right now. I worked my butt off for that paper. I mean literally. I revised so hard for so long that the chair I was sitting on became anti matter to my butt and they annihilated each other in order to produce countless amounts of gamma photons in opposite directions. Perfectly obeying the law AE=AMC^2 (A representing delta). I currently no longer have a butt.

sell your life!

Reply 1392

Small123

15

Original post by RESIDUAL FLUX

what did u you guys get for the gradient on the first page, i got gyrometric ratio as the quantity

I'm not sure what the gyrometric ratio is but on wikipedia it states that it's units are Coulomb per kilogram hence surely that would be not be the units of the gradient?

Reply 1393

tom28

Original post by RESIDUAL FLUX

but my freind said it was capacitance but how?? cause isnt capacitance charge/voltage??

Original post by Small123

I'm not sure what the gyrometric ratio is but on wikipedia it states that it's units are Coulomb per kilogram hence surely that would be not be the units of the gradient?

The gradient was V/Q. Capacitance is Q/V, so the gradient is 1/capacitance.

Reply 1394

RESIDUAL FLUX

Original post by tom28

The gradient was V/Q. Capacitance is Q/V, so the gradient is 1/capacitance.

oh crap.... that was so obvious, thanks man, i least i know what i got wrong now!!

Reply 1395

RESIDUAL FLUX

BTW, for 'evolution of the universe' i have a different opinion as i am atheist and therefore suggested that God, the ALMIGHTY himself, has dwelled us in this loveable earth where life strives and water flows.. and it was created in 7 days.. day 1: adam and eve, etc , do u think ill get some marks cause i am not wrong, it is what i choose to believe!!

Reply 1396

Oromis263

2

Original post by RESIDUAL FLUX

BTW, for 'evolution of the universe' i have a different opinion as i am atheist and therefore suggested that God, the ALMIGHTY himself, has dwelled us in this loveable earth where life strives and water flows.. and it was created in 7 days.. day 1: adam and eve, etc , do u think ill get some marks cause i am not wrong, it is what i choose to believe!!

as i am atheist

God, the ALMIGHTY himself

as i am atheist

God, the ALMIGHTY himself

as i am atheist

God, the ALMIGHTY himself

Wait, what?!

Reply 1397

alexbumpoo

Original post by Moiraclaire

The attenuation coefficient was in cm and the answer was in cm, don't bother converting.
3.3 x =ln2
simple...

I think :L
the answere was 0.21cm I think

yeah because if you wanna convert its not 0.033 its actually 333 because its 3.3 per cm so per metre its 333