OCR Physics B - Rise and fall of the clockwork universe - 28th Jan

I thought the paper was pretty straightforward.

Reply 43

tiggerplease

That... was... ridiculous

Reply 44

dan9

i found it quite mixed really :s-smilie:

i didnt have a clue about the question to do with the copper particles melting when they oscillate at 15% of d or sumat like that... anyone enlighten me?

Reply 45

LambieUK

Thought it was awful.

Reply 46

dan9

i found it quite mixed really :s-smilie:

i didnt have a clue about the question to do with the copper particles melting when they oscillate at 15% of d or sumat like that... anyone enlighten me?

On that question i used E = 1/2 k x^2 and E = kT, so k x^2 = 2kT

However that was one question where I don't think I got the correct answer - I got a ridiculous 49,000K.

Reply 47

Ksaw92

dan9

i found it quite mixed really :s-smilie:

i didnt have a clue about the question to do with the copper particles melting when they oscillate at 15% of d or sumat like that... anyone enlighten me?

Hey,

E = 1/2 k (force per unit displacement) A²

A= 0.15 x d (found in earlier question)

E = k (boltzmann) T

T = E/k (boltzmann)

Sub in E found earlier and you get the melting point :-)

I got around 1300K

Reply 48

bluespacetiger

What was up with the question on young modulus and spring constant/density having the same units? As far as I could tell they don't...

EDIT: I for one could have used a bit more time too. (or a shorter paper)

Reply 49

Katie_08

I thought this paper was harder than all the past papers we did but i did expect it after last years June exam though. Even the momentum question was quite tricky.

Reply 50

josh_a_y

2

The paper was bad... :frown:

definitely resitting in june :smile:

Reply 51

kylesawhney

Hey,

E = 1/2 k (force per unit displacement) A²

A= 0.15 x d (found in earlier question)

E = k (boltzmann) T

T = E/k (boltzmann)

Sub in E found earlier and you get the melting point :-)

I got around 1300K

Shoot! I did exactly that but used 1.15 instead of 0.15 :eek3:

Reply 52

Didnt have enough bloody time again. The section A wasnt as easy as it normally is, and i didnt have a clue about the atom question. Also some nice questions like the velocty-KE graph and the piston question. But yeh... no time to check answers so i dont know.

Reply 53

I'm surprised you didn't have enough time - I found myself with 15 minutes to check answers.

Reply 54

ojpowermake

I just wish we had lines for the questions where u gotta write. And wasn't expecting that one on electron emission, didn't do that this year. Felt sorry for the new guy in my class who didnt do it last year.

Reply 55

Mmm... yeh i guess the electron was synoptic, i just remembered it from chemistry though lol. Et=KT, then E=hf, finally v=yf. There was also a boltzmann factor part i seem to remember?

Reply 56

Skadoosh

12

Wasn't a bad paper, wasn't the best either.

Felt Section A was rather tricky, especially the wording of question 3. Obviously the one about the copper melting was a bit hard as well.

TBH, I was expecting it to be worse so overall not too bad.

Reply 57

Samw1se

I'm surprised you didn't have enough time - I found myself with 15 minutes to check answers.

Really!? Did you miss a page or just do everything double time lmao, i did my calculations twice the first time round... but that only takes like 5 min extra!

Reply 58