OCR ADVANCING PHYSICS B G494 EXAM MONDAY 18th June

YES! Practically same answers throughout, numerical answers at least.

For 13b) you make the denominators common for kinetic energy and then add the numerators together, GmM - 2GmM = -GmM or something like that.

Frequency i either go 3.00 or 3.50, not sure, probably rounding somewhere.

And for question 5 i put both smaller change in T and larger initial N.

Actually for the fridge one I also got 8.6x10^24 not 5.7, and when i subbed it back into the equation, p1v1/t1 = 79.9 and p2v2/t2= 80, which works, not sure about the 5.7 you got :/

It asked to show that the number of particles was roughly 6x10^24, and I used the values of:
p = 1x10^5, v = 0.23, k =1.4x10^-23 and T = 288? :s-smilie:

Reply 181

Anthony Soprano

Original post by Oromis263

It asked to show that the number of particles was roughly 6x10^24, and I used the values of:
p = 1x10^5, v = 0.23, k =1.4x10^-23 and T = 288? :s-smilie:

Ohhhh yeah yeah I got the same value exactly, I mixed up reading the markscheme, i was thinking of d) Calculate the new pressure, 8.8x10^4 Pa for some reason, probably because thats where i got an 8.something answer :smile:

Same answers throughout then :rolleyes:

Reply 182

Oromis263

2

Original post by Anthony Soprano

Ohhhh yeah yeah I got the same value exactly, I mixed up reading the markscheme, i was thinking of d) Calculate the new pressure, 8.8x10^4 Pa for some reason, probably because thats where i got an 8.something answer :smile:

Same answers throughout then :rolleyes:

Cool.

Really hoping for a high mark on this to go with my coursework, so I can try even out my G495 if it actually went worse than I feel it went. :smile:

Reply 183

EricEdwardSelvaraj

What did you guys get for your cswk?

I got 20 on the practical and 9 on the essay, but I am worried that the exam board might lower it.

Reply 184

Oromis263

2

Original post by EricEdwardSelvaraj

What did you guys get for your cswk?

I got 20 on the practical and 9 on the essay, but I am worried that the exam board might lower it.

The same, hoping they moderate my essay up to a 10, my teacher docked it one because it was long (12 pages) but that was mostly bibliography and diagrams, whereas the actual body of text was under the 2000 words. My experiment report was beasty :biggrin:

Reply 185

lukas1051

18

The calculate epsilon question was very difficult, I don't think many candidates will have got it. I certainly didn't, but hopefully I'll get 1 or 2 method marks. In general I thought it was a relatively difficult paper, but I think I personally did well. :smile:

I think the mention of resonance was important for the question about the bike - I got f = 3.4Hz which when you think about it is about the same frequency it would be forced to vibrate at when going over bumpy ground at a reasonable speed.

(edited 11 years ago)

Reply 186

EricEdwardSelvaraj

Original post by Oromis263

The same, hoping they moderate my essay up to a 10, my teacher docked it one because it was long (12 pages) but that was mostly bibliography and diagrams, whereas the actual body of text was under the 2000 words. My experiment report was beasty :biggrin:

They won't do it individually though. It's either all go up or all come down.

Reply 187

Oromis263

2

Original post by EricEdwardSelvaraj

They won't do it individually though. It's either all go up or all come down.

Well that sucks, luckily my teacher is very harsh (I would say). :smile:

Perhaps I'll get lucky :P

(edited 11 years ago)

Reply 188

Oromis263

2

Original post by lukas1051

The calculate epsilon question was very difficult, I don't think many candidates will have got it. I certainly didn't, but hopefully I'll get 1 or 2 method marks. In general I thought it was a relatively difficult paper, but I think I personally did well. :smile:

I think the mention of resonance was important for the question about the bike - I got f = 3.4Hz which when you think about it is about the same frequency it would be forced to vibrate at when going over bumpy ground at a reasonable speed.

I considered that as I walked out. I am pretty sure I got all the other technical terms in, but when I considered 3.4Hz I would agree that that is roughly the frequency at which you would bounce on a bumpy track. :smile:

I would agree, but would hazard a guess that the boundaries will be similar to the January paper so roughly:

54 - 100%
49 - A*
44 - A
39 - B
35 - C
31 - D
27 - E

Perhaps? :smile:

Reply 189

EricEdwardSelvaraj

Original post by Oromis263

I considered that as I walked out. I am pretty sure I got all the other technical terms in, but when I considered 3.4Hz I would agree that that is roughly the frequency at which you would bounce on a bumpy track. :smile:

I would agree, but would hazard a guess that the boundaries will be similar to the January paper so roughly:

54 - 100%
49 - A*
44 - A
39 - B
35 - C
31 - D
27 - E

Perhaps? :smile:

I mentioned resonance, but I did not link it in with the calculated value i.e. 3.4 Hz, do you think it was necessary to mention that?

Reply 190

deejayy

1

Original post by Oromis263

I considered that as I walked out. I am pretty sure I got all the other technical terms in, but when I considered 3.4Hz I would agree that that is roughly the frequency at which you would bounce on a bumpy track. :smile:

I would agree, but would hazard a guess that the boundaries will be similar to the January paper so roughly:

54 - 100%
49 - A*
44 - A
39 - B
35 - C
31 - D
27 - E

Perhaps? :smile:

What is the maximum raw mark you can get in this paper?

Reply 191

lukas1051

18

Original post by Oromis263

I considered that as I walked out. I am pretty sure I got all the other technical terms in, but when I considered 3.4Hz I would agree that that is roughly the frequency at which you would bounce on a bumpy track. :smile:

I would agree, but would hazard a guess that the boundaries will be similar to the January paper so roughly:

54 - 100%
49 - A*
44 - A
39 - B
35 - C
31 - D
27 - E

Perhaps? :smile:

Yeah those sound about right to me.

Reply 192

Oromis263

2

Original post by deejayy

What is the maximum raw mark you can get in this paper?

60. The boundaries I posted are similar to the ones in January, and I'd say the papers were of roughly the same difficulty. Usually they are lower, last June had boundaries of 50 - 100%, 45 - A*, 40 - A, then 35 31, 27, 23 for B C D E respectively. :smile:

Reply 193

jackofwack

For the question about the activation energy 'epsilon' in the fridge, was there any other way of doing it without having to solve two rather daunting simultaneous equations? I ended up dividing two equations and using Some indices work on the exponentials. It was however only 3 marks and uses a level of maths that some candidates won't have so what was the easier way? Unless I did it completely wrong :colondollar:

? (I got 1.6x10^-19 (or-18) or something by the way)

Reply 194

luketaylor777

for the conservation of momentum question did everyone get the velocity to be negative? (Going left after the collision)

Reply 195

lukas1051

18

Original post by luketaylor777

for the conservation of momentum question did everyone get the velocity to be negative? (Going left after the collision)

Yup. Can't remember the number, -0.57 maybe(?), but I remember having -311 in there somewhere...

Reply 196

Yarpie

9

Original post by jackofwack

For the question about the activation energy 'epsilon' in the fridge, was there any other way of doing it without having to solve two rather daunting simultaneous equations? I ended up dividing two equations and using Some indices work on the exponentials. It was however only 3 marks and uses a level of maths that some candidates won't have so what was the easier way? Unless I did it completely wrong :colondollar:

? (I got 1.6x10^-19 (or-18) or something by the way)

I ended up with 1.609x10^-19 unrounded answer.

You had to re-arrange to eliminate C. A question like this came up in Core 4 for AQA and it was worth four marks so I don't think it's fair that it's three marks for the exact same method in Physics, ah well.

So you have;

I'll put x=e/kt just for ease of writing.

500=Ce^x1
2=Ce^x2

2e^x1=500e^x2

250=e^x1/e^x2

ln250=ln((e^x1/e^x2))

ln250 = lne^x1 - lne^x2

ln250 = x1 - x2

ln250 = epsilon(1/k(temperature for 500)-1/k(temperature for 2)

Reply 197

PhysicsGirl

OP

7

Original post by jackofwack

For the question about the activation energy 'epsilon' in the fridge, was there any other way of doing it without having to solve two rather daunting simultaneous equations? I ended up dividing two equations and using Some indices work on the exponentials. It was however only 3 marks and uses a level of maths that some candidates won't have so what was the easier way? Unless I did it completely wrong :colondollar:

? (I got 1.6x10^-19 (or-18) or something by the way)

If you mean saying that 2= e^-epsilon/288k and 500=e^-epsilon/253k and then dividing to get 0.004=e^(epslion/k (1/288 - 1/253)), then solving that by taking the natural log of both sides, then I'm pretty sure that's a correct method.
That's the way I did it, and I think that's the right answer. I think it's GCSE-level maths, not A-Level (except perhaps the fact that the base of the powers is 'e' and you have to take logs, which is in the physics course), so I'm not sure there's an easier method.

Reply 198

jackofwack

Original post by Yarpie

I ended up with 1.609x10^-19 unrounded answer.

You had to re-arrange to eliminate C. A question like this came up in Core 4 for AQA and it was worth four marks so I don't think it's fair that it's three marks for the exact same method in Physics, ah well.

So you have;

I'll put x=e/kt just for ease of writing.

500=Ce^x1
2=Ce^x2

2e^x1=500e^x2

250=e^x1/e^x2

ln250=ln((e^x1/e^x2))

ln250 = lne^x1 - lne^x2

ln250 = x1 - x2

ln250 = epsilon(1/k(temperature for 500)-1/k(temperature for 2)

I got to the same final stage apart from I had two equations from the two conditions set (i.e temperatures) but to eliminate 'C' I divided them instead. Seems we both got to the same answer anyways though :smile:

Reply 199

Amy-Rose

8

Was stressing about the graph on the first page, couldn't decide between A and B! :')