** HL Physics Before / after **

aarond280

Could someone put up a diagram of how two prisms can be used in binoculars. Thanks

Undeadfred

Was this a question on a past paper?

kingcobra

Welcome to Google Images my friend! :P

aarond280

a question like this came up on a mock. Thanks

Eurovisionmad

kingcobra wrote: »

Welcome to Google Images my friend! :P

That diagram is a bit . . . much all you need is two prisms reflecting through 180 and then maybe a lens on either side!

Undeadfred

On question 12.b in the 2008 paper, it asks to calculate the change in pitch, but the question doesn't give you a value for the speed of sound? I thought it was 330 m/s so i used that but then the marking scheme used 340 m/s. The value for the speed of sound isn't in the log tables so and i wasn't sure what to use. I only used 330 cause i recalled seeing it in other questions on other years. usually they give you values like that but it can differ so how were we meant to know to use 340 instead of 330?

Kingkumar

umm it's always 340 in air ...i don't think it changes

Eurovisionmad

Kingkumar wrote: »

umm it's always 340 in air ...i don't think it changes

Yes it does, it changes with temperature and pressure and a lot of other things!

Have you checked the front page the value might've been printed there! Though if such a question comes up they would have to give the value as its not constant like the speed of light!

Monsieur Folie

If ever you're stuck in an exam and you're convinced a value is not printed that should be, or you can't find a value in the log tables or you've forgotten one you're supposed to remember, it's probably better to make up a value and plow ahead picking up marks for method than to just leave it blank!

Is this the physics thread now then? :P

How is everyone set for this? Currently, I'd barely pass, but I have 5 days to whip it into shape and aim for a good B at least. Our mock was sh*t though. =/

Peregrine

Kingkumar wrote: »

umm it's always 340 in air ...i don't think it changes

It changes with temperature, humidity, air pressure and many other things.

For temperature the formula is:

C = C0 + 0.60t

Where C0 is the speed of sound at 0 degrees C, constant 331.5 m/s and t = the temperature

Undeadfred

Monsieur Folie wrote: »

If ever you're stuck in an exam and you're convinced a value is not printed that should be, or you can't find a value in the log tables or you've forgotten one you're supposed to remember, it's probably better to make up a value and plow ahead picking up marks for method than to just leave it blank!

Yeah that's what i was thinking as well but its not printed anywhere in the paper. I have no idea whats up with that they should give you it like

Monsieur Folie wrote: »

How is everyone set for this? Currently, I'd barely pass, but I have 5 days to whip it into shape and aim for a good B at least. Our mock was sh*t though. =/

I feel pretty confident. If i sat the paper tomorrow I'd probably get the A1 but I'm going to make sure i get it with a day worth of study on it

Monsieur Folie

Ah yeah. A nice paper would see me out nicely with an A1 alright but physics has always been my weakest science. I'd be happy with a B1 but after 5 days of hard work who knows, I might scrape the A

Raeral

Anyone else planning to sit the paper without looking at electricity at all :P

Chikablam

I absolutely hate Electricity. Nuclear stuff all the way!

kingcobra

Our physics teacher left out the whole electricity section saying we don't need to do it :eek: I had to cover it through grinds. I've no idea what mark I could get either as we never did class tests so I don't know what standard I'm at, as with the others in the class. If I have a good exam I might scrape an A but I'm definitely looking for B.


But lads, particle physics is where the craic's at :cool:

I_ENJOY_BATHS

I really want an A1 but on all papers I do I end up just short of the 90% mark, what's the best thing to do for the last few days to maximise my chances of getting an A1?

Glee_GG

Kingkumar wrote: »

umm it's always 340 in air ...i don't think it changes

It does change but our teacher told us for the purposes of the exam, they don't give you the value as your supposed to take it as 340m/s and just know it!

Glee_GG

Need the A1, hopefully a decent heat/modern physics and particle physics question and I'll be set!

Undeadfred

I_ENJOY_BATHS wrote: »

I really want an A1 but on all papers I do I end up just short of the 90% mark, what's the best thing to do for the last few days to maximise my chances of getting an A1?

Do as many past paper questions as you can, focus on where your falling down so you can bring up the marks in the places your loosing them. Exam technique is essential.

Don't waste time by doing past papers and correcting them to reassure yourself, bit of a waste of time at this late in the game. Just try to get exam focused so use past papers make sure you have good exam technique

ItsCon

Does anybody know if they're putting the values back on the paper or if we'll have to use log book again? There was a lot of problems last year with people taking values at different decimal places which gave a wide range of correct answers

carlos123455

Anyone has list of demonstrations we need to know for the exam?

Leaving Cert Student

ItsCon wrote: »

Does anybody know if they're putting the values back on the paper or if we'll have to use log book again? There was a lot of problems last year with people taking values at different decimal places which gave a wide range of correct answers

Ambiguous values such as speed of sound will be on paper. constants like speed of light may not be.

worrx

Looks like I'm the only one who'd be happy to even get a C! :P

I'm leaving out mechanics because I find it extremely irritating!

Chikablam

kingcobra wrote: »

Our physics teacher left out the whole electricity section saying we don't need to do it :eek: I had to cover it through grinds. I've no idea what mark I could get either as we never did class tests so I don't know what standard I'm at, as with the others in the class. If I have a good exam I might scrape an A but I'm definitely looking for B.


But lads, particle physics is where the craic's at :cool:

What the hell was your teacher playing at? I hate it, but it's pretty big

curly135

worrx wrote: »

I'm leaving out mechanics because I find it extremely irritating!

Every mechanics question I've ever done from the past papers has been a disaster, I'm steering clear of it :P

A whole weekend for cramming before Physics, be grand. :pac:

Brendan1234

Does anyone know if we can take the speed of light as 3x10^8 ms-1 or do we have to use the value in the table books? I know for most constants you use the value in the table books but I think I saw in the 2011 or 2012 marking scheme that they used 3x10^8, thanks.

Copper_pipe

G by Freefall or Co planer forces for Q1 i reckon

ynwa14

I'm terrified of this exam I really need a C but I'd do anything to get higher than a B3. Anyone got any tips on revising/predictions? It's my weakest science but I'm sticking with HL so I really need a move on

lostatsea

carlos123455 wrote: »

Anyone has list of demonstrations we need to know for the exam?

Definitions, formulae, demonstrations, STS (pure gold): http://www.studentxpress.ie/Physics/L&Ssummary.pdf

Undeadfred

lostatsea wrote: »

Definitions, formulae, demonstrations, STS (pure gold): http://www.studentxpress.ie/Physics/L&Ssummary.pdf

A lot of those definitions I've never seen before in my life. If we just learn all the definitions in Dan O'Regan's book should we be grand?

HPMS

lostatsea wrote: »

Definitions, formulae, demonstrations, STS (pure gold): http://www.studentxpress.ie/Physics/L&Ssummary.pdf

Never even knew that existed!! Thanks for that

I'm hoping for an A but I still have electricity to revise but I have the weekend for that so should be grand. Considering the experiments go for so many marks, should hopefully have full marks there provided no sneaky questions are asked like the mocks!

Any tips for getting the A? Is it just knowing definitions, how to the maths stuff and knowing how things work etc? Once you know all that, are you sorted?