WJEC A2 PH5 Exam 18th June

About the Hall probe, can anyone remember which side they said was positively charged?

Reply 61

Original post by Hydeman

About the Hall probe, can anyone remember which side they said was positively charged?

I think I put right side, but can't remember (do you remember which way electrons were travelling+magnetic field direction?)

Reply 62

Original post by philgreek

I think I put right side, but can't remember (do you remember which way electrons were travelling+magnetic field direction?)

I put right as well. Electrons I think were travelling into the paper (difficult to describe otherwise) so the current must have been coming out and the B-field was going up, I think. I'm doing it again and it does seem like the force on the electrons would be left and hence the right side would be positively charged but I've cocked up FLHR before...

Reply 63

fha96

Original post by JakeDaw

Capacitor question
Radioactivity of technetium-99?
Hall probe question
Nucleon binding energy
Flux linkage through copper square

Unfortunately those are the only ones I can remember, and are not necessarily in the correct order

Posted from TSR Mobile

Original post by philgreek

Last one was cyclotron question.

I think order was:
capicitors
nucleon binding energy
flux linkage through copper square
Cyclotron
Radioactivity of technetium
Hall probe

Cheers guys, that's put my mind at rest haha. That binding energy per nucleon graph question was awful I reckon, what did you all do for it?

Reply 64

Original post by fha96

Cheers guys, that's put my mind at rest haha. That binding energy per nucleon graph question was awful I reckon, what did you all do for it?

Yeah was a lot worse than the usual easy marks that can be picked up from the binding energy questions, skipped the question on my first run through of the paper and was uncertain exactly how to answer some stuff.

Part i.) I just talked about how fusion+fission both release energy and increase stability of produced nuclei and compared heavier/lighter nuclei and what they undergo, relative to iron. Though predicting marking points for that was hard.

part ii.) mbe/n of deuterium was 1.1MeV and there were two nucleons, so 2.2 MeV would be released.

part iii.) I calculated binding energy of each nucleus based on graph and equated everything, to get energy released (I got about 200 MeV).

Reply 65

What do people think the grade boundaries will be like? Virtually dying with worry right now that I'll end up with a B in physics...

Reply 66

wb25

3

Does anyone have a copy of the paper they could put up ?

Reply 67

Original post by wb25

Does anyone have a copy of the paper they could put up ?

Haven't got a paper (hoping someone posts it too). But these are the questions I can remember, accounts for all the marks in materials option, almost all the marks in section A but only half in case study (can you remember any other questions in the case study?).

1a.) What is the charge stored by each capacitor (2)
1b.) Energy stored by all capacitors (2)
1c.) What is the resistance for discharge graph (3)
1d.) initial current (2)
1e.) time for 99% charge decrease(2)

2a.) fusion/fission explained in terms of energy/stability(4)
2b.) binding energy of deuterium (2)
2c.) Energy released in fission reaction (4)

3ai.) magnetic flux when parallel to field lines (3)
3aii.) Magnetic flux when perpendicular
3b.) Why is current induced in copper coil (3)
3c.) direction of force with Lenz’s law explained (2)
3d.) current flowing based on resistance given (5)

4a.) Derive frequency in cyclotron (2)
4b.) Frequency for specific case (1)
4c.) Calculate velocity of carbon (3)
Another part?

5a.) calculate half life (2)
5b.) Why only gamma radiation (3)
5c.) initial mass of technetium (4)

6a.) Label positive face (1)
6b.) add voltmeter (1)
6c.) Calculate Vhall (3)
6d.) Why electrons have no work done by electric field (1)
6e.) current based on drift drift velocity (I=nave)(2)
Another part?

57 of 60 marks accounted for

Case study:

7a.) explain why not all energy into ball’s gpe (2)

7b.) explaining in your own words why model and reality don’t agree (3)

7c.) table with blanks for increase/decrease and what forces were(3)

7d.) show consistent units for change in mass/change in time equation (1/2)

7e.) calculate speed based on values given (2)

7f.) Explain why no heat flow in bottle when it lifts off (1)

7g.) Explain why the internal energy decreases (1)

13/14 out of 20 accounted for

Materials:

10a.) Why glass is brittle (2)
10b.) Why can glass be accurately fractured (2)
10c.) Why prestressed glass is strong (2)
10d.) Proving young’s modulus for sample (1)
10e.) work done to break sample (3)
10f.) Drawing graph for alloy B (3)
10gi.) creep definition (1)
10gii.) necking definition (1)
10h.) Drawing creep graph(2)
10i.) work hardening-how it works and how it makes it stronger (3)

20 out of 20 accounted for

(edited 8 years ago)

Reply 68

Original post by Hydeman

What do people think the grade boundaries will be like? Virtually dying with worry right now that I'll end up with a B in physics...

Last year grade boundaries for PH5 were:

last year
100% = 85/100
90% = 79/100
80% = 73/100
70% = 63/100
60% = 53/100

and PH5 accounts for 44% of the Alevel year. In my opinion the paper was challenging and harder than last year. However, generally doing tests in exam conditions is more stressful so people find it harder. The grade boundaries are likely to be similar to last year. However, wjec grade boundaries have fluctuated a lot from year to year as so few people do the board.

How well did you do last year and how did you find PH4 and the experimental task?

Reply 69

Original post by philgreek

Last year grade boundaries for PH5 were:

last year
100% = 85/100
90% = 79/100
80% = 73/100
70% = 63/100
60% = 53/100

and PH5 accounts for 44% of the Alevel year. In my opinion the paper was challenging and harder than last year. However, generally doing tests in exam conditions is more stressful so people find it harder. The grade boundaries are likely to be similar to last year. However, wjec grade boundaries have fluctuated a lot from year to year as so few people do the board.

How well did you do last year and how did you find PH4 and the experimental task?

Last year I got a B but I resat PH2 and found it a breeze except for a couple of marks but so did others - and that's an important consideration as last year you needed over 80% raw marks to get an A on PH2 because people generally found it easy.

I really wish I'd done better at AS to be honest because even if I made the maximum possible improvement on PH2 my AS mark still only comes to 250/300 and I doubt I'll be getting full marks on PH2 although I think I'll come close.

I thought PH4 was alright although I've since been feverishly counting the marks I lost and I reckon it comes to about 7 - 8 marks which is somewhat bad news for a module which has a history of churning out 70/80 grade boundaries for an A on a harder paper than this year's.

PH6 - I think I lost about 3 - 4 marks on the data analysis but the experimental I think went okay. On the very last question on the experimental they asked you to verify the value of the half life from your graph using given values and I realised that those values weren't actually in my recorded results but I wrote a note saying that the half life would be the same for two stated values that differed by a factor of 2. I stated the values I used and why I couldn't use the ones they wanted and got the right answer so I think it'll be alright. That was all I had trouble with on the experimental and my teacher said that they'd worded it poorly and should have said something like "using appropriate values from the graph, verify..."

I really hope the grade boundaries are dirt-low this year. The timing on this exam is ridiculous. I missed out 4- and 5-markers that I could otherwise have done just for want of time. :frown:

Reply 70

Original post by Hydeman

Spoiler

AS (240/300) - So from AS your max is 250. In PH2 you were close to full marks, let's just say you drop 10 ums (which was 6 marks last year). So in AS 240.

PH4 (97/108) - Dropping 7-8 marks in PH4 has never been below 90%. So let's say you have 97 ums (/108). And don't forget that in PH4 ums-raw conversion is very steep, so a few extra marks would likely get you the full 108.

PH6 (48/60) - The 3-4 marks and perhaps that extra unknown one lost will likely be about 80% -> 48 ums.

Which means From the other 5 modules you would have about 385 (could be more as well), so to get an A you need 95/132 in PH5, which (based on last year) would be about 65/100. And grade boundaries could be lower this year as well as I believe the general consensus is that this was a hard paper.

I'm sure PH5 went better than you think. It can be easy to fixate on the 4/5 markers you didn't do and panic, while forgetting how many solid answers you gave to other questions.

So don't worry I'm sure you'll make your A in physics :smile:

and there's no point in worrying about it for a couple of months while waiting for results, enjoy the holiday \o/ .

Reply 71

Original post by philgreek

AS (240/300) - So from AS your max is 250. In PH2 you were close to full marks, let's just say you drop 10 ums (which was 6 marks last year). So in AS 240.

PH4 (97/108) - Dropping 7-8 marks in PH4 has never been below 90%. So let's say you have 97 ums (/108). And don't forget that in PH4 ums-raw conversion is very steep, so a few extra marks would likely get you the full 108.

PH6 (48/60) - The 3-4 marks and perhaps that extra unknown one lost will likely be about 80% -> 48 ums.

Which means From the other 5 modules you would have about 385 (could be more as well), so to get an A you need 95/132 in PH5, which (based on last year) would be about 65/100. And grade boundaries could be lower this year as well as I believe the general consensus is that this was a hard paper.

I'm sure PH5 went better than you think. It can be easy to fixate on the 4/5 markers you didn't do and panic, while forgetting how many solid answers you gave to other questions.

So don't worry I'm sure you'll make your A in physics :smile:

and there's no point in worrying about it for a couple of months while waiting for results, enjoy the holiday \o/ .

Haha, thanks for reassuring me. xD I'll try to forget about it till results day and hope for the best. :smile:

Still wish I'd done better at AS since it takes so much pressure off - in Biology I had 270/300 last year and the second exam didn't go great but the coursework and first exam were wonderful but it takes the pressure off because I know I only need to get 210/300 to get that A, even though I was kind of gutted at missing out on an A*. Oh well, we'll see.

And thanks again. :biggrin:

Reply 72

Original post by philgreek

Haven't got a paper (hoping someone posts it too). But these are the questions I can remember, accounts for all the marks in materials option, almost all the marks in section A but only half in case study (can you remember any other questions in the case study?).

1a.) What is the charge stored by each capacitor (2)
1b.) Energy stored by all capacitors (2)
1c.) What is the resistance for discharge graph (3)
1d.) initial current (2)
1e.) time for 99% charge decrease(2)

2a.) fusion/fission explained in terms of energy/stability(4)
2b.) binding energy of deuterium (2)
2c.) Energy released in fission reaction (4)

3ai.) magnetic flux when parallel to field lines (3)
3aii.) Magnetic flux when perpendicular
3b.) Why is current induced in copper coil (3)
3c.) direction of force with Lenz’s law explained (2)
3d.) current flowing based on resistance given (5)

4a.) Derive frequency in cyclotron (2)
4b.) Frequency for specific case (1)
4c.) Calculate velocity of carbon (3)
Another part?

5a.) calculate half life (2)
5b.) Why only gamma radiation (3)
5c.) initial mass of technetium (4)

6a.) Label positive face (1)
6b.) add voltmeter (1)
6c.) Calculate Vhall (3)
6d.) Why electrons have no work done by electric field (1)
6e.) current based on drift drift velocity (I=nave)(2)
Another part?

57 of 60 marks accounted for

Case study:

7a.) explain why not all energy into ball’s gpe (2)

7b.) explaining in your own words why model and reality don’t agree (3)

7c.) table with blanks for increase/decrease and what forces were(3)

7d.) show consistent units for change in mass/change in time equation (1/2)

7e.) calculate speed based on values given (2)

11/12 out of 20 accounted for

Materials:

10a.) Why glass is brittle (2)
10b.) Why can glass be accurately fractured (2)
10c.) Why prestressed glass is strong (2)
10d.) Proving young’s modulus for sample (1)
10e.) work done to break sample (3)
10f.) Drawing graph for alloy B (3)
10gi.) creep definition (1)
10gii.) necking definition (1)
10h.) Drawing creep graph(2)
10i.) work hardening-how it works and how it makes it stronger (3)

20 out of 20 accounted for

On the case study, the last two questions were about explaining why no heat flows in the expansion and then using the first law of thermodynamics to show why the gas cools over time.

(edited 8 years ago)

Reply 73