OCR Physics B A2 synoptic pre-release discussion

I think we need to find this teachers forum, my teacher went on about it too.

Reply 44

I found the site I think you guys are talking about and managed to find this:

http://www.tim.swchs.net/AdvancesinPhysics.doc

Reply 45

jgosden

Great Find - Thanks alot datr :smile:

Reply 46

paulharrison also posted up some questions his teacher gave him here in the other thread if you haven't seen it yet.

Reply 47

Yep, that document is what I was on about :yy:

Reply 48

Acomodo

Can literally anything can up in section B? Or is there always specific topics that they tend to chose, i.e. Redshift, SHM etc.?

Reply 49

Acomodo

Also, has any1 got the answers for those questions from the teachers' forum?

Reply 50

No, someone else asked me for them in the other thread so I looked around the teacher's forum but I couldn't find any answers.

Reply 51

Acomodo

Ah well, cheers anyway.

Quick question: No.9 of those teachers forum questions it says that entropy is defined as kln(W).

It then asks for the entropy of a pack of new playing cards.

As there is only 1 way of arranging a pack of new playing cards, does this mean that the entropy is 0 [ln(1)] ????

Just sounds a bit odd to have an entropy of 0 :confused:

Reply 52

eguk

omg all of those questions are impossible!! the exam better not be that difficult. also does anyone know the marks of the exam, ie how many for section A and B, as i am more confident about section B.

Reply 53

Jonno_

5

eguk

omg all of those questions are impossible!! the exam better not be that difficult. also does anyone know the marks of the exam, ie how many for section A and B, as i am more confident about section B.

Section A is worth roughly 2/3 of the marks and Section B about 1/3. Sorry.

Reply 54

The paper I have has 59 marks for A and 31 marks for B. Not sure if they change or not. Man this exam could go really ****ty and whether I make my firm or insurance uni hinges on this.

Reply 55

justaddwater1

can anyone post the link to the teachers forum?

Reply 56

enrico palazzo

I don't think we ever use a negative value of entropy in this paper, it's the magnitude of the change in enthalpy. I think. Correct me if i'm wrong.

The stuff I'm more worried about is like refractive index stuff and young's modulus, ie

n = sin i / sin r

cancel out the sins,

n = i/r

that's how i'm going to remember it at least. :suitc:

BTW I just realised that formula is in the formula booklet. You might look to learning Sin C = 1/n instead as that isn't.

Also there doesn't seem to be a teachers forum, it's a mythical place, let's not speak of it no more.

Question, what's the difference between conductivity and conductance, I realise the difference mathematically but do they both measure how easily a material conducts electricity?

Reply 57

Conductance is specific to a certain object, a wire say. Where as conductivity is specific to a certain material, e.g. copper.

So two copper wires of different radii and length will have different conductance but the same conductivity.

Reply 58

DanC

datr

I found the site I think you guys are talking about and managed to find this:

http://www.tim.swchs.net/AdvancesinPhysics.doc

Hmmm, that's got me a bit worried. How the hell do you do the first question?

a) A train is travelling at 40ms-1 along a level stretch of track. It draws 100Amps at 25,000V from the overhead line. What is the force required to keep it moving?

Reply 59

dra2k4