Physics Predictions...

techguy

Anyone here got any ideas on what might be coming up on the physics paper ths year?
Anything at all is helpful to me at this stage to help ease my nerves..


Oh Noooo!! Less Than A Week Left :eek: :eek:

exiztone

Well, you have a bit more than a week until the physics. As far as I know, the calculating G with the SHM of a pendulum has a high chance of coming up.

It's crazy the way physics is such a broad course and difficult too, whereas economics is so short and sweet. They should really have a common difficulty standard for all subjects

Waltons

e=mc^2 and/or photoelectric effect. Apparently it's 100 years since Einstein explained these

sephirosis

For Section A they usually ask one electricity exp, one mechanics, and 2 from light/sound/heat. so far they have never asked g by pendulum, or Newtons second law (f proportional to a) exp's, so they seem likely to come up. in electricity resistance against temperature for metal/thermistor has never appeared so it might be worth a look, or they could just go for the old favourites of ohm/joule. as for the other light/sound/heat ones they are a little harder to predict. snells law maybe but it seems to easy. an actual SHC question has not come up yet but it probably wont since you get to choose your own method be it electric/mechanical so its difficult to set a fair question but you never know. i cant see the sonometer experimanet coming up since f against L was on a few years back, and more recently f against both T and L. Speed of sound in air maybe?

Section B is always varied. If ohm isnt on section A it will prob be Q 8. i would say know the theory and definitely know your maths for the circuits, they might throw in a rheostat thingy used as a potential divider. as someone said already photoelectric effect with einsteins equation looks good. option q doesnt change much. and finally if ohm isnt on either section A or q8 it will almost surely be a part of q12. they love it that much.

remember in the end predictions are often futile though (the ironing is delicious) good luck all

hellsbells

ah its funny how much of that i dont understand! Im doin physics as Gaeilge!

*Angel*

exiztone wrote:

It's crazy the way physics is such a broad course and difficult too, whereas economics is so short and sweet. They should really have a common difficulty standard for all subjects

It would be nigh impossible to set a common difficulty standard for all subjects, everyone has difficulties in different subjects, I am pretty good at physics and don't find it too bad but I'm terrible at languages :mad: , and I'm sure economics would actually kill me (tried it in 4th year).

*Angel*

If you're stuck for time in physics the things to cover are:

- mandatory experiments
- mechanics (always up)
- option question

But I really think that most of the course has to be covered if you're going for a high grade, however you could still get a high grade if you cover a certain amount of topics really well. There is after all quite a lot of choice on the paper.

OTliddy

First of all, I don't advise relying on these posts for your leaving cert, and im not jus saying that to be a fart. Every year, they cover all the topics in some way. However, if you must, here are some areas that they havent asked much about yet:
Section A
-F=ma
-Thermistor/resistor variation with temperature
-Diode
-Snell's law

Section B
Derivations of acceleration
Circular motion........dammit
Geometrical optics
electrical circuits
electromagnetic induction
Einstein(just cos its his 100th anniversary of relativity)
Harmonics
Good luck evryone!

Joe_duffy

Kepler's third law t2 proportional to r3
/the t2= 4(pie)2*r3/gm is comin up...what out for the photoelctric effect and circular motion too..

daxon

i hate circular motion. the F=ma is defo cuming up .an't been on the exam yet

stevoxbx

Kepler's third law t2 proportional to r3
/the t2= 4(pie)2*r3/gm, what chapters that in the book?! I dont remember it :eek:

*Angel*

stevoxbx wrote:

Kepler's third law t2 proportional to r3
/the t2= 4(pie)2*r3/gm, what chapters that in the book?! I dont remember it :eek:

It's part of circular motion.

eoinmurphy

sephirosis wrote:

remember in the end predictions are often futile though (the ironing is delicious) good luck all

I never knew Ironing could be delicious,
Irony on the other hand......

upmeath

Learn all your formulae and q5 is three grades in the bag.
Learn your formulae and mechanics and your two parts of four for q11 are pretty much sorted
Learn whatever experiments haven't come up and breeze through the experiments that appeared in 2002

Johnerr

Anyone got any dead certs, or near enough to dead certs for the physics paper? need to pass it, hopefully a c, but thats pushing it

*Angel*

Johnerr wrote:

Anyone got any dead certs, or near enough to dead certs for the physics paper? need to pass it, hopefully a c, but thats pushing it

Particle Physics

Johnerr

doing the applied electrictiy option

*Angel*

Johnerr wrote:

doing the applied electrictiy option

I've done both but I'd do the particle physics because it's generally an easy topic, I hate drawing the motors/generators... in the applied elec.

Other than that if you concentrate on the experiments, mechanics and your option you're at least looking at a C.

:Keith:

Particle Physics is real easy. I don't see why my Physics teacher thinks it's hard.

Johnerr

what chapters are the machanics chapters?

Vikings

How do I pass the pass paper? What do I need to learn on sunday night?

vote4pedro

If you want to just scrape a pass, just learn the experiments. That section is worth 30%, the questions are always the same (draw a graph, state two precautions etc.) and they also come up in different parts of the long questions, so combined with having picked up the odd bit of info over the years you'll easily get 10% in that section, added to your experiments giving you a pass of 40%.

Also, whenever asked for a precaution in the experiments, you can almost always say
a) Use bigger values of water/voltage/distance, to reduce percentage error
and
b) Avoid error of parallax when reading measurement.

chicken_food

vote4pedro- sounds like somebody went to pat doyles class!

StevieK5000

Good theory but you cant get all 30% in exps by studying them for the first time the night before, it would be some massive fluke if you could!

vote4pedro

chicken_food wrote:

vote4pedro- sounds like somebody went to pat doyles class!

P. Diddy is the man !

Experiments are simple, very easy to score high marks in once you learn the procedure and what the graph should look like.

chicken_food

Certainly is! Hes a genius! Especialy his jokes!

Legend

dross

ah, c'mon, he's a bit of cúnt. his formula goes: make a really really really obvious joke that you saw coming 20 minutes ago then when everyone stops laughing spew some physics. and his notes are bollocks. but he's alright.

JackKelly

yes, how he condenses the entire course into a handful of notes is complete bollox.....
I don't particularly like the notes, as the physics is boring, but as notes go, they are fairly good. Better than doing it by the 300pg+ book.

StupidLikeAFox

vote4pedro wrote:

Also, whenever asked for a precaution in the experiments, you can almost always say
a) Use bigger values of water/voltage/distance, to reduce percentage error
and
b) Avoid error of parallax when reading measurement.

c) wear safety goggles

Always works in chemistry anyway!

vote4pedro

I think I'm going to leave out Nuclear Physics and Magnetism, can't get my head around either. I reckon I'll be safe enough with knowing my experiments, Mechanics, Light, Sound, Heat, Particle Physics and having a general grasp of electricity, probably not enough to do a full long question on elec. though.

Richard_Fonzie

I didn't think his notes (p. doyle) were that great either, but his classes are excellent! I nearly cried when he made that analogy between the way the geiger-muller tube works and dance halls in the 50's

chicken_food

I dont remember that one, which one was that?

Richard_Fonzie

During a class on radiation: How the negative electrons/ions staying at one side of the tube and the positive ions at the other is just like how adolescents were rooted to each side of a dance hall, until one of the positive ions comes across and grabs negative ion...

OTliddy

ColHol wrote:

c) wear safety goggles
Always works in chemistry anyway!

not sure that's what they're looking for. It's more precautions as in precautions to reduce percnetage error i think...

JackKelly

Richard_Fonzie wrote:

During a class on radiation: How the negative electrons/ions staying at one side of the tube and the positive ions at the other is just like how adolescents were rooted to each side of a dance hall, until one of the positive ions comes across and grabs negative ion...

lmao.

Late Night with Pat Doyle

sci0x

I've never used wear safety googles as a chemistry precaution!, maybe as a final last restort when i've used all my other last resort precautions id slap it down. Very iffy just like the error or parallax one for physics. Last resort only. Think of all the good precautions 1st

OTliddy

sci0x wrote:

Very iffy just like the error or parallax one for physics.

I thought the parallax one was perfectly okay.

stevoxbx

It is. Aslong as no paralax is necisery for the experiment.

rasher_b2

ColHol wrote:

c) wear safety goggles

Always works in chemistry anyway!

our teacher told us to NEVER say that...

Richard_Fonzie

Yeah I can't think of any physics experiments where you need to wear goggles, except perhaps the radiation demonstration experiments, and they're just silly anyway.

Africa

Experiments wise, in 2004:
Freefall G
Funda Freq of F with length
Nichrome wire
Wavelength of Monocromatic light
2003:
Boyles Law
SLH of vaporisation of water
Focal length of converging lens
Joules Law
2002: Law of Equilibrium
SLH of Ice
Funda Freq of F with tension
variation of current I with Pot V.

Anyway. I say for this year learn the following:
Ohms Law (variation of resistence of thermistor/Metal with temp) yes thats 2 different experiements very the same...easy enough.
Calibration Curve of Thermometer using merc as standard
SHC of water
Sound speed in Air
Length and period of Pendulum, find G.
Measurement of Velocity and Acceleration
Newtons Second law, A proportional to F
Schnells Law
Focal length of lens's.

thats about ten, i say that at least 3 of those will come up.. If not...i will eat my teacher.

Johnerr

Richard_Fonzie wrote:

Yeah I can't think of any physics experiments where you need to wear goggles, except perhaps the radiation demonstration experiments, and they're just silly anyway.

fundemental frequency of a stretched string with tension, incase wire snaps you need goggles

*Angel*

Africa wrote:

SHC of water

I've never done that, don't you get a choice of SHC of a body or a liquid?

Richard_Fonzie

^^^ In the Folen's book it's just SHC of water.

Richard_Fonzie

But I guess according to this it's both:

MEASUREMENT OF THE SPECIFIC HEAT CAPACITY OF A METAL BY AN ELECTRICAL METHOD

Apparatus

Joulemeter, block of metal, heating coil to match, beaker, lagging, thermometer accurate to 0.1 °C, glycerol, electronic balance and a low voltage a.c. supply.

Procedure

1. Find the mass of the metal block m.
2. Set up the apparatus as shown in the diagram.
3. Record the initial temperature θ1 of the metal block.
4. Plug in the joulemeter and switch it on.
5. Zero the joulemeter and allow current to flow until there is a temperature rise of 10 °C.
6. Switch off the power supply, allow time for the heat energy to spread throughout the metal block and record the highest temperature θ2.
7. The rise in temperature Dq is therefore θ2 – θ1.
8. Record the final joulemeter reading Q.

Results

Mass of metal block m =
Initial temperature of the block θ1 =
Final temperature of the block θ2 =
Rise in temperature = θ2 – θ1 =
Final joulemeter reading Q =

Calculations

The specific heat capacity of the metal c can be calculated from the following equation:

Energy supplied electrically = energy gained by the metal block

Q = mc .

MEASUREMENT OF SPECIFIC HEAT CAPACITY OF WATER BY AN ELECTRICAL METHOD

Apparatus

Joulemeter, calorimeter, heating coil, beaker, lagging, thermometer reading to 0.1 °C, electronic balance and a low voltage a.c. supply.

Procedure

1. Find the mass of the calorimeter mcal.
2. Find the mass of the calorimeter plus the water m1. Hence the mass of the water mw is m1 – mcal.
3. Set up the apparatus as shown. Record the initial temperature θ1.
4. Plug in the joulemeter , switch it on and zero it.
5. Switch on the power supply and allow current to flow until a temperature rise of 10 °C has been achieved.
6. Switch off the power supply, stir the water well and record the highest temperature θ2. Hence the rise in temperature is θ2 – θ1.
7. Record the final joulemeter reading Q.

Results

Mass of the calorimeter mcal =
Mass of the calorimeter plus the water m1 =
Mass of the water mw = m1 – mcal =
Initial temperature of water θ1 =
Final temperature θ2 =
Rise in temperature Dq = θ2 – θ1 =
Final joulemeter reading Q =

Calculations

Given that the specific heat capacity of the calorimeter ccal is known, the specific heat capacity of water cw can be calculated from the following equation:

Electrical energy supplied = energy gained by water + energy gained by calorimeter

Q = mwcw + mcalccal .

Notes

If a polystyrene container is used in place of the copper calorimeter, then the energy gained by the water is equal to the electrical energy supplied since the heat capacity of the container is negligible.

The energy equation now reads: Q = mwcw .
If a joulemeter is unavailable, electrical energy can be supplied to the heating coil from a power supply unit connected in series to an ammeter and rheostat. A voltmeter must be placed in parallel with the heating coil to measure the potential difference and a stopwatch used to measure the time of current flow.
Switch on the current and the stopwatch simultaneously. Adjust the rheostat to maintain a constant current. Allow the current to flow until a temperature rise of 10 °C has been achieved. Record the steady current I and voltage V readings. Switch off the current and the stopwatch simultaneously. Record the time t in seconds.

If a calorimeter is used the energy equation is: VIt = mwcw + mcalccal .

If a polystyrene container is used the energy equation is: VIt = mwcw .


MEASUREMENT OF THE SPECIFIC HEAT CAPACITY OF A METAL OR WATER BY A MECHANICAL METHOD

Apparatus

Copper calorimeter, copper rivets, beaker, boiling tube, lagging, thermometer accurate to 0.1 °C, heat source and electronic balance.

Procedure

1. Place some copper rivets in a boiling tube. Fill a beaker with water and place the boiling tube in it.
2. Heat the beaker until the water boils. Allow boiling for a further five minutes to ensure that the copper pieces are 100° C.
3. Find the mass of the copper calorimeter mcal.
4. Fill the calorimeter, one quarter full with cold water. Find the combined mass of the calorimeter and water m1. Hence the mass of the water mw is m1 – mcal.
5. Record the initial temperature of the calorimeter plus water θ1.
6. Quickly add the hot copper rivets to the calorimeter, without splashing.
7. Stir the water and record the highest temperature θ2. The fall in temperature of the copper rivets is 100 °C – θ2. The rise in temperature of the calorimeter plus water is θ2 – θ1.
8. Find the mass of the calorimeter plus water plus copper rivets m2 and hence find the mass of the rivets mco.
Results

Mass of the calorimeter mcal =
Mass of the calorimeter plus the water m1 =
Mass of the water mw = m1 – mcal =
Initial temperature of water θ1 =
Initial temperature of rivets 100° C
Initial temperature of calorimeter θ1 =
Final temperature of water θ2 =
Final temperature of rivets θ2 =
Rise in temperature of water = θ2 – θ1 =
Rise in temperature of calorimeter = θ2 – θ1 =
Fall in temperature of rivets = 100° C - θ2
Mass of calorimeter plus water plus rivets m2 =
Mass of rivets mco = m2 – m1

Calculations

Assume that heat losses to the surroundings or heat gains from the surroundings are negligible.
Given that either the specific heat capacity of water cw or the specific heat capacity of copper cc is known, the other specific heat capacity can be calculated from the following equation:

Energy lost by copper rivets = energy gained by copper calorimeter + the energy gained by the water

mcocc = mcalcc + mwcw .

If cw is known, then cc can be calculated or alternatively if cc is known, cw can be found.

Notes

If a polystyrene container is used in place of the copper calorimeter, then the energy gained by the water is equal to the energy lost by the copper rivets. The energy equation now reads:
mcocc = mwcw .

*Angel*

It's ok, I just checked the syllabus and it says water or a metal.

Richard_Fonzie

There's a pretty comprehensive list of all of the experiments Here.

stevoxbx

That would have been so helpful 2days ago! :eek:

*Angel*

^ very true

StupidLikeAFox

Africa wrote:

thats about ten, i say that at least 3 of those will come up.. If not...i will eat my teacher.

Im sure he/she'd look forward to that...

Webmonkey

ColHol wrote:

Im sure he/she'd look forward to that...

hehe