G492 9th June 2016 Discussion - (inc. pre-release)

This is an exam discussion for the OCR B (Advancing Physics) AS paper - G492.

Link for the course specification:
http://www.ocr.org.uk/Images/74952-specification.pdf

The link for the pre-release article:
http://www.ocr.org.uk/Images/291729-unit-g492-advance-notice-article-june-2016.pdf

Feel free to discuss the exam, the course content and the pre-release article. Any resources posted will greatly be appreciated.

(edited 8 years ago)

Reply 1

Fox Corner

21

Original post by Fangedbeast

...

I've added this post to the A Level directory thread, which you can find here

let me know if you make or find any more exam threads and I'll add them to the directory

OP

bump .

OP

bump .

i'll get back to this thread after i've done the g491 paper (resit) next tuesday

OP

bump .

http://hyperphysics.phy-astr.gsu.edu/hbase/class/phscilab/restube2.html
https://en.m.wikipedia.org/wiki/End_correction
For reasonance experiment.

http://www.chabotcollege.edu/faculty/shildreth/physics/hookeslaw.htm
https://www.pa.msu.edu/courses/2013summer/phy251/labfiles/Lab%209%20spring.pdf
For Hookes Law

http://www.ocr.org.uk/Images/79603-question-paper-unit-g492-understanding-processes-experimentation-and-data-handling.pdf
http://www.ocr.org.uk/Images/78224-unit-g492-advance-notice-article-january-2012.pdf
For pre release for G492 Jan 2012 where dot plots have come up before.
BUT THIS WAS FOR MEASUREMENT OF TIME AND NOT HOOKES LAW SO BE CAREFUL.

For sysematic error, refer to the end of the revision guide I have uploaded with the target and bullseye.

I would make sure you are 90% confident on A2 stuff by this exam as everyone who is doing this exam will be doing A2 units as well so knowing OCR, there may be some A2 questions in here too.
@FranklyPineapple

(edited 7 years ago)

Any predicted questions for the pre-release? There were so many more resources last year because obviously now it's just a resit thing :frown:

I will be so mad if they do put A2 stuff in, I'm only retaking this exam to up my 4th AS grade, I don't do A2 Physics 😂😢

Reply 8

Fangedbeast

OP

2

Original post by kennz

http://hyperphysics.phy-astr.gsu.edu/hbase/class/phscilab/restube2.html
https://en.m.wikipedia.org/wiki/End_correction
For reasonance experiment.

http://www.chabotcollege.edu/faculty/shildreth/physics/hookeslaw.htm
https://www.pa.msu.edu/courses/2013summer/phy251/labfiles/Lab%209%20spring.pdf
For Hookes Law

http://www.ocr.org.uk/Images/79603-question-paper-unit-g492-understanding-processes-experimentation-and-data-handling.pdf
http://www.ocr.org.uk/Images/78224-unit-g492-advance-notice-article-january-2012.pdf
For pre release for G492 Jan 2012 where dot plots have come up before.
BUT THIS WAS FOR MEASUREMENT OF TIME AND NOT HOOKES LAW SO BE CAREFUL.

For sysematic error, refer to the end of the revision guide I have uploaded with the target and bullseye.

I would make sure you are 90% confident on A2 stuff by this exam as everyone who is doing this exam will be doing A2 units as well so knowing OCR, there may be some A2 questions in here too.
@FranklyPineapple

I highly doubt there will be any A2 content for an AS exam. Regardless of exam board or subject, AS exams are only meant to cover AS content and below (inc. GCSE) and not any higher. They're only allowed to ask questions/test you on synoptic parts of the course at most i.e. things learned previously. The same would apply to the A2 paper, it can only ask questions from GCSE, AS and A2 Physics. I'd be very surprised if there were things directly taken from the A2 course that is asked on the AS paper.

Anyhow, thank you for the resources (I would upvote you but TSR won't allow me to because I already upvoted you in the G495 thread you made :P)

(edited 7 years ago)

Reply 9

kennz

8

Original post by Fangedbeast

I highly doubt there will be any A2 content for an AS exam. Regardless of exam board or subject, AS exams are only meant to cover AS content and below (inc. GCSE) and not any higher. They're only allowed to ask questions/test you on synoptic parts of the course at most i.e. things learned previously. The same would apply to the A2 paper, it can only ask questions from GCSE, AS and A2 Physics. I'd be very surprised if there were things directly taken from the A2 course that is asked on the AS paper.

Anyhow, thank you for the resources (I would upvote you but TSR won't allow me to because I already upvoted you in the G495 thread you made :P)

Its the last year of the course and seeing how OCR are quite sneaky with things, it's not a bad thing to prepare for the worst. It should be against some sort of rule but in 2014, the G491 paper used a lot of information from outside the syllabus (but the questions were on stuff we learnt, just very applied). And to be honest, being confident with A2 stuff earlier is not a bad idea, it means that we can be that much better for G494 and G495. However, I agree it may be a long shot. Don't worry about the upvote as well.

Reply 10

Kristofa

in G492, there are the 'carry out the test to prove' questions. This is a stupid question but if the values for the constant are really close e.g. 48.7, 48.2, and 48.5, in the conclusion you would say that the test carried out fits the relationship given in the question? When do you say it isn't? Only when the numbers are completely different e.g. 0.099, 0.076 and 0.056, you'd disagree with the relation? Thanks in advance guys!

Reply 11

username2463673

9

Original post by Kristofa

in G492, there are the 'carry out the test to prove' questions. This is a stupid question but if the values for the constant are really close e.g. 48.7, 48.2, and 48.5, in the conclusion you would say that the test carried out fits the relationship given in the question? When do you say it isn't? Only when the numbers are completely different e.g. 0.099, 0.076 and 0.056, you'd disagree with the relation? Thanks in advance guys!

To be honest I like them cause they're easy marks. Basically, you're looking for a pattern so it's not always necessarily a constant- I.e. if the values increases there is the possibility of a relationship depending on the equation used.

In terms of the constant you want them roughly similar, but they'll never be identical.

Reply 12

Kristofa

Original post by JimJam456

To be honest I like them cause they're easy marks. Basically, you're looking for a pattern so it's not always necessarily a constant- I.e. if the values increases there is the possibility of a relationship depending on the equation used.

In terms of the constant you want them roughly similar, but they'll never be identical.

I really appreciate your reply, thank you so much :smile:

Reply 13

Flunked German

1

Original post by kennz

http://hyperphysics.phy-astr.gsu.edu/hbase/class/phscilab/restube2.html
https://en.m.wikipedia.org/wiki/End_correction
For reasonance experiment.

http://www.chabotcollege.edu/faculty/shildreth/physics/hookeslaw.htm
https://www.pa.msu.edu/courses/2013summer/phy251/labfiles/Lab%209%20spring.pdf
For Hookes Law

http://www.ocr.org.uk/Images/79603-question-paper-unit-g492-understanding-processes-experimentation-and-data-handling.pdf
http://www.ocr.org.uk/Images/78224-unit-g492-advance-notice-article-january-2012.pdf
For pre release for G492 Jan 2012 where dot plots have come up before.
BUT THIS WAS FOR MEASUREMENT OF TIME AND NOT HOOKES LAW SO BE CAREFUL.

For sysematic error, refer to the end of the revision guide I have uploaded with the target and bullseye.

I would make sure you are 90% confident on A2 stuff by this exam as everyone who is doing this exam will be doing A2 units as well so knowing OCR, there may be some A2 questions in here too.
@FranklyPineapple

Have you got a link for the end of revision guide for the systematic error?

Reply 14

kennz

8

Original post by Flunked German

Have you got a link for the end of revision guide for the systematic error?

yes I've uploaded the file

Original post by kennz

yes I've uploaded the file

Cheers

Reply 16

Fangedbeast

OP

2

I've just noticed something, the pre release says " The experiment is repeated ten more times. The results,  presented as a simple dot plot, are shown in Fig. 1." but there are a total of 12 dots when theoretically there should be 10 dots, if not 11.

Is this a typo by OCR? Or is it like that on purpose made to trip people up?

Reply 17

physics_maths

1

Original post by Fangedbeast

I've just noticed something, the pre release says " The experiment is repeated ten more times. The results,  presented as a simple dot plot, are shown in Fig. 1." but there are a total of 12 dots when theoretically there should be 10 dots, if not 11.

Is this a typo by OCR? Or is it like that on purpose made to trip people up?

I saw that too when helping a student go through it.

It's likely to be a typo like you said or it could be a set up for a question along the lines of:
"One dot was plotted accidentally, state and justify which dot this could be"
where then you could talk about the 1.8 cm saying it's out of range of 2 times the uncertainty calculated from the other values and furthest from the mean.

Reply 18

kennz

8

My predicted questions for section C (40 Marks)

Dot Plot
Calculate mean and spread (2) Standard, ignore value of 1.8
Decide that a value is an outlier (1) Standard
Source of systematic error (2) Using a ruler; Parralax error, edges have been rubbed off due to friction.
Effect of systematic error on final value (2) X is a small value so any uncertainty here has significant effect on measurement of spring constant.
Improvement of experiment(2) You want to improve value of x so take more measurements of x or use an electronic ruler or something like that (if it exists)
Total (9)

Systematic error
Difference between accuracy and precision (2) Precsision is due to the resolution of an instrument i.e. uncertainty., so the observations taken could be very similar if there is high precision. Accuracy is dependent on systematic error, if there is low systematic error, then result is accurate. A value can still be precise if its inaccurate and vice versa.
Ammeter systematic error (2) The zero error of 0.01 below 0 current, current is therefore smaller than it actually is. This is constant sytematic bias
Measuring tape systematic error (2) Measuring tape is stretched so real value is greater than measured value. This is varying systematic bias.
Effect of systematic error on final value (2) Already mentioned, could ask you to do this for an experiment not mentioned in the pre release article.
Question where num of observations is increased which is an improvement (2) As you increase number of observations, then effecct of uncertainty is minimised, e.g. if you take 100 observations instead of 10, the uncertainty is reduced by a factor of 10.
Total (10)

Reasonance tube
Graph of reasonance peak: y=Amplitude (or intensity) against x=Length (L)
This will show two Peaks, one very large one for L1 and one very small one for L2.
You can then find the distance between each peak using a rule which gives you a value for lambda/2
(2)
Draw loops of wavelengths for L2 or L1 and ask you to label nodes and antinodes (2) Standard question.
Explaination of how standing wave is formed inside reasonance tube (3) Be specific for antinodes (max amplitude, constructive interference, in phase etc) and mention how it reflects of bottom of tube.
Table of data : calculate missing values (2)
Graph of L2-L1 (y axis) against 1/f or T (remember 1/T = f) on the x axis
Plot data
Calculate gradient which is speed of sound divided by 2.
Use this to find value for speed of sound.
(4)
Label end correction on diagram with antinodes and nodes. (1)
Estimate value of c, usually between 0.6 and 0.3 of the radius of the reasonance tube (1)
Big question on sytematic error - effect of end correction on final value of speed of sound (4)