OCR Physics B G495 Field and Particle Pictures June 21st 2011 Exam Thread

did anyone put that the difference in speed of the two wavelengths due to the refraction would cause the superposition effect to break down?

i totally guessed that

did anyone put that the difference in speed of the two wavelengths due to the refraction would cause the superposition effect to break down?

i totally guessed that

it wasnt as bad as i thought it would be actually

yeah exactly that.. but i ended up dividing the emf by two... took a risk! if it turns out wrong it will only be a mark

Oh, why did you divide by two, is it because it said average? Hmmmm... that's a good point.

Yeah, it went better than a lot of the past papers I have done, I think.

See my post above, that was what I put . . .

Mass of U-235 per year:

Multiply Watts/power given by number of seconds in a year, get total energy used per year.

Divide total energy by energy released per fission to get no of nuclei that decay.

Get actual mass of one U-235 nucleus by multiplying 235 by u to get mass in kg

Multiply no of nuclei by the mass...result?

Oh, why did you divide by two, is it because it said average? Hmm... that's a good point.

Yeah, it went better than a lot of the past papers I have done, I think.

On the one with the ring, i thought it was an average because of the way the ring was moving. It wasn't spinning it was just sort of falling, so i thought the bottom part of the ring which didn't move much only cut a few lines, whilst the top part covered a larger distance cutting more lines. So i thought the normal calculation could be the average.

I think it did spin, but it only did 1/4 of a rotation. If it just feel without spinning then the flux lines through the area of the coil would be constant, I think.

it wasnt as bad as i thought it would be actually

yeah exactly that.. but i ended up dividing the emf by two... took a risk! if it turns out wrong it will only be a mark

I used the normal equation, i thought it would be average because the normal flux linkage/time graph is a curve, but we calculated the straight line gradient between the points and 0... so i guessed that our equation didn't take into account this curve?

I got 4.35 people and rounded it up to 5. I hate those questions haha

I was generally pretty happy with the paper, hopefully it will be the 2nd A for my durham offer

Yeah that's what I did.

Geekchick, what did you put for the 800 minima question?

Just spotted this:
http://www.bbc.co.uk/news/education-13857911

Was this our physics paper or a different one? Sorry if it's already been mentioned on here.

Erm .. The one asking for wavelength?
2d = phase difference i think of n/2(lambda) but n is odd, so i think thats the same as your 2n+1 lambda version?
I can't really remember
I seem to remember i got somehting like 525 nm for a wavelength somewhere down the line ..? it was like 525 accurate so i presumed it was right?

did anyone else get like 4.96 kg for the mass of uranium used??