Physics

eirebhoy

Do you think I'll be safe going into the Physics exam knowing very little about the whole electricity section?

In the folens sample papers only 1 experiment comes up, at the most, on Electricity in Section 1.

Also, in the papers Question 6 is always on Mechanic. Is that always going to be like that? Does anyone know the actual layout of the exam (ie. is their a specific order of questions in each topic, like Maths)?

I'm going to do Q5, Q6 (if its definitely on Mechs), Q10(a), Q12, and one more question that I find easiest.

Is this a good way to go into the Exam?

Dont be at yourself

Between experiments, short questions and full questions, Mechanics is worth around 33% of the paper, apparently.

You could skimp on Electricity, but that would leave you with little or no choice with regards to the questions so you'd want to be very familiar with everything else.

Bottle_of_Smoke

Know modern physics, not too hard.

Electromagnetism and heat also seems to have a good chance of coming up

selling_irish

YOU DON'T NEED TO KNOW ELECTRICITY TO GET AN A1

Personally, I'm just looking to pass Physics. I got 40% in the mock, but only because Boyle's Law Experiment was question 1! And that's so not gonna happen in the real thing. It's the easiest experiment ever!

Anyway, yeh you can leave out the entire electricity section and still get an A1.

In Section A, you have 4 experiments and have to answer 3. Only one of them is on electricity, and you have to answer three in total. Answer the OTHER three!

In Section B, you have 8 questions and have to answer 5. Only a maximum of 3 full questions will be on Electricity, so answer the OTHER five!

Where electricity appears in an "Answer two out of the three following parts" question, you can still avoid it and get full marks in that question.

I would be completely ****ed if I had to answer electiricity! It's so ****ing boring and complicated and pointless!

Good Luck

C ye

Boston

I have to wonder why you people bothered to do physics in the first place. Electricity is simple, infact physics in simple. Btw its answer 2 out of 4 not 3 in question 12, and there doesn't have to be a question on electricity in section a

Sangre

I would have thought electricity was one of the most relevant topics on the LC, all about the mains etc.

CuLT

Might be relevant, not necessarily easy tho Sangre.

Sangre

Originally posted by selling_irish

I would be completely ****ed if I had to answer electiricity! It's so ****ing boring and complicated and pointless!

Good Luck

C ye

I was referring to the pointless part, should of qouted. Anyway I agree, it is a bitch, hate all the static electricity >8(

PHB

All of physics is easy once you learn the book off by heart and do all the sample questions.

Thats the way to get an A1, do every single sample paper until you can do them with your eyes closed

If you're rushed for time, learn the second half of the course, its easier to anwser on.

Electricity - Magnetism - Modern Physics - Particle Physics
Then go back and Learn Mechanics and Light
Then move onto Heat and Sound

If you can do every mandatory experiment you have just about passed
Then build on from that!

eirebhoy

If anyone is using Real World Physics I recommend doing the whole workbook rather than read the book. Everything you need is in it.
Do the first 80 pages and you have Light, Mechanics, Heat and Sound done which is more or less what I'm doing.

BTW if anyone doesn't agree with me that all the info you need is in the workbook please tell me, I don't want to miss a load of important stuff!

pseudonym

just learnt off the 119 major defintions. Im too lazy to do exam questions and its too far away to start panicking.
might look over da formulae and derivations now.

The sample papers are a bit crap, i think personally.

Delphi91

Originally posted by Boston
I have to wonder why you people bothered to do physics in the first place....

I was begining to wonder the same myself!!!

All I've read in the last few days on threads here is "How much of the course can I leave out?"

I've seen some "interesting" strategies for getting marks.

Gotta say that selling-irish has an interesting angle! This person has all the answers for getting an A1, yet they only want to "PASS"!! If I knew how to get an A1 in any exam, the last thing I would settle for is a pass......

Someone else recommends learning off the book!!

The last thing that physics is about is "learning off". In physics, if you've worked at it at all, you'll see that the vast majority of the course is about application. If you understand the principles behind the topics, then the application is very straight forward.

Mike

PHB

Yeah the application is very straight foward.

However unless your an uber smart physics person, which I'm not, I think your best bet is to learn off the book.
You do so by doing every single possbiel exam paper question and looking up the anwser each time you dont know it.
Then when you've gone through all the exam papers, you do it again, and again until you know all the anwsers off by heart

A1

Sev

I'd have to agree. That's what I find makes the subject seem like such a small work load. There isnt a whole lot on the course, provided you understand it well. Learn the basics from the chapters and you should be able to apply the cop on then to form strategies to tackle any question. But I still believe spending a few hours to flick through every page in the book, and memorise the intricacies and details would be beneficial.

Delphi, if you're going to be correcting any LC physics papers this summer, look out for one in green pen with messy writing, an A1 would do nicely.

Delphi91

Originally posted by PHB
Yeah the application is very straight foward.

However unless your an uber smart physics person, which I'm not, I think your best bet is to learn off the book.
You do so by doing every single possbiel exam paper question and looking up the anwser each time you dont know it.
Then when you've gone through all the exam papers, you do it again, and again until you know all the anwsers off by heart

A1

I agree up to a point. There is no substitute for exam papers when it comes to practicing for the real thing. However, my only concern would lie with your final statement - "until you know the answers off by heart".

I've seen this done by people who go off and learn ALL about a topic. Then a question comes up, say where you have to apply a principle to explain something. Problem is, they don't know that part, but they can tell you ALL about the topic itself. That is useless in a physics exam.

Don't get me wrong, I'm all for exam papers - my students are green from doing them. Just be careful that you don't "learn off" a method which you will then apply to the question, even if it isn't the correct way to get the answer.

Best of luck to all physics students in the exam on Monday.

Mike

P.S. Sev, you wouldn't by any chance be suggesting that an examiner might look favourably on one specific script, now would you????? No, I didn't think so...:-) Anyway, I'm supervising, not correcting, so........

PHB

Well, I actually understand it all fairly well, its just, I don't really want to have to "work out" the anwser in the exam.

I'd rather that I've done it so many times I can just speil it out on the page.

ella minnow pea

Originally posted by PHB
All of physics is easy once you learn the book off by heart

thats the thing innit

thats what makes the Leaving a joke

i hate ****in learin off crap, it is no measure of intelligence whatsoever.

We Are Not Parrots, People.

You dont have to be smart to do well in the LC, just learn stuff off. What the hell is up with that like!!

Stoopid bloody exams.


/edit - ok i've just read over that and it sounds a bit socialist. Sorry, tis the 3 hours of sleep in the last 48 talking.

sionnach

ur right, leaving vert is a test of how much study u do and how much stuff u learn off by heart. Even subjects such as maths are more based on learning information off than on teh students ability. Instead of thinking "how do i do this question" matsh students think "where have i seen an example like this b4" I think college entry should be decided on aptitude tests as well. Its kinda stupid how for example a maths genius can get rejected for a maths course just because he/she does badly in french and biology i think SAT test r continuous assessment shoud be introduced, and streaming as well, tho thats 2 late for me now why wasnt i born in norway............*sigh*

PHB

If I ran a college I'd want the average person who works hard instead of the super smart lazy person.

And most people who work hard are normally fairly smart people who want to push themselves.
I love hearing the people who claim if it was all based on aptitude tests the results would be a lot different

Sev

Delphi, if you're still there.

Why 'exactly' do you use glycerol/liquid paraffin in the experiment for investigating change in resistance of a metallic conductor/thermistor with temperature. My physics book asks the question, but doesnt actually provide the answer in the preceding text.

Also, whats the deal with the experiment to measure the specific heat capacity of a metal? It's not mentioned in the physics book.

Sangre

I was going to ask you in a pm, but I figured this would help everyone.

Looking over the Edu. Comp Sample paper 3 Q8 I think on heat. it asked some quesiton about bimetallic strip and its application in a fire alarm. I know I did this in JC, but I cant remember it. Now I friend says we're supposed to know the Jc course aswell? This cant be true can it?

It also gave a numerical q involving the U-value, but I just multiplied the area by the u-value and tempature and it seemed to work out. But where the hell did the sample papers get this stuff?

I would also like to know the glycerol thing

Sev

Oh, and personally, I dont think its safe going into the physics exam and leaving out a quarter, if not a third of the course. Yes, you might be able to get buy without answering an electricity question, but you're not exactly leaving your options open.

I suppose im in the best position, seeing that I dont really have a perference, whatever question looks most straight forward and involves least writing, im straight for. Although, having said this, I'm sure regardless, when you electricity fearing bunch open up your papers on monday, you probably wont go near the electricity even if you do put in the effort to revising it over the weekend.

In my opinion if the reason you dont like electricity, is because you have some kind of conceptual difficulty in understanding it, then at this stage, I dont think you can make up the ground in three days. What I find often, is that im detracted from a question if I see a part to it that seems a bit nit picky, vague, ambiguous or involves some kind of minor uncertainty that might involve me losing a mark or two. Thats my major worry, making sure that there are at least 8 questions on the paper that I can answer fully and correctly, and having electricity under the belt increases that probability.

Anyway, theres nothing stopping you from picking up a physics book right now, and flicking over all the electricity chapters. It might take you like what? 2 hours? If its not clicking tho, it could be a dangerous misappropriation of resources at this stage.

Anyway, thats my 5c

Sangre

Pffft, that was hardly worth 5c, what with inflation and all...

Sev

The bimetallic strip, speaking in the past tense here, was just these two different metals bonded together. One with a higher tendency to expand with increasing temperature such that when it happened the strip would strain and bend slightly. Being made of metal and all, it conducts electricity, and as the temperature increases it would bend to touch another conductor completing a circuit, current would flow through, and off goes the fire alarm. They're used in thermostats too, same principle, and in MCBs along with electromagnets apparently.

Sangre

I knew the jist of it, but I definetly wouldn't have answered it in an exam, would have put me way off.

But do we need to know Jc stuff?

Sev

Well, in fairness, I dont think there is a lot that was on the junior cert science physics curriculum that isnt specifically on the leaving cert. Either way, the question was from a sample paper, and I have seen them frequently stray off the course and/or give dodgy questions often lacking specific detail that the leaving cert questions tend to quote in excess.

phaxx

I believe the bimetallic strip is on the syllabus, it's been mentioned by my teacher a few times.

Dunno about everyone else, but I love electricity.

As far as I know, the glycerol is used because it has better thermal conductivity, and gives a better reflection of the temperature. I could be way off though, someone please correct me if I am!

Sangre

Lower specific heat capacity??

Delphi91

Originally posted by phaxx
...As far as I know, the glycerol is used because it has better thermal conductivity...

That's pretty much the explanation which I use. Generally, the resistance wire is placed inside a testube of glycerol/liquid paraffin which is then placed in a beaker of water.

Water is a poor conductor of heat but a good conductor of electricity whereas glycerol is the other way around. And since its probably not a good idea to have bare wires which are conducting a current sitting in a testube of water, the glycerol is used instead!

As for the bi-metallic strip, I can't find any mention of it specifically on the syllabus (higher or ordinary level). Howvere, there is nothing stopping a teacher from mentioing it as an example of the use of thermal expansion. I presume that people are aware of the STS section of the course (Science, technology and Society). This tends to be the practical application of physics to the everyday world. Well, a bi-metallic strip is a good example of this. It's used in fire alarms, electric kettles, thermostats in immersion heaters, etc.

It works by having two metals different metals welded together. Each expands at a different rate. When you heat them, one tries to expand faster than the other, but since they are welded together, this causes them to bend, with the metal which has the higher thermal expansivity on the outside of the bend.

In a fire alarm, you arand it so that if the alarm gets hot, a bi-mettalic strip bends and makes an electrical contact causing the alarm to sound. In a thermostat, adjusting the temperature up causes the strip to be bent a little further away from the contacts, so that the heater stays on longer before the strip bends enough to shut off the heat.

Hope this helps a bit.

Mike

Sangre

Thanks for the quick reply, as long as its not directly on the course. If you have the Edu comp papers, could you look at sample paper 3 q8. Would you be ask to work something out with the U-value?

Delphi91

Originally posted by Sangre
...If you have the Edu comp papers, could you look at sample paper 3 q8. Would you be ask to work something out with the U-value?

I don't have them, sorry.....

Checked out what it says in the syllabus, and U-Values are mentioned in the STS section. All that it says is:

"U-Values: Use in domestic situations"

I'd be surprised if they have a calculation-type question on it (oh, and I wouldn't put too much faith in SAMPLE papers either!).

Mike