[silentlife]

(Original post by ehtisham_1)
most of the time its just stating the obvious

yeah

[thenumber2goose]

I'm reading the examiners report for the Jun09 paper. For question 4b (a 6 mark, long answer question), the report states: "Candidates in a few centres appeared to use mnemonics to remember the elements necessary in answering this type of question; this seemed to work quite well."

I was wondering if anyone could enlighten me as to what these mnemonics are?

[silentlife]

(Original post by leeandrewarmstrong)
I'm reading the examiners report for the Jun09 paper. For question 4b (a 6 mark, long answer question), the report states: "Candidates in a few centres appeared to use mnemonics to remember the elements necessary in answering this type of question; this seemed to work quite well."

I was wondering if anyone could enlighten me as to what these mnemonics are?

It would be good to know too

[uxa595]

Da*** is mnemonics?

[vVShabbaVv]

(Original post by leeandrewarmstrong)
I'm reading the examiners report for the Jun09 paper. For question 4b (a 6 mark, long answer question), the report states: "Candidates in a few centres appeared to use mnemonics to remember the elements necessary in answering this type of question; this seemed to work quite well."

I was wondering if anyone could enlighten me as to what these mnemonics are?

Elements of the question. Could be a set plan? Just had my tutor go over this with me. Basically you plan the question first as you can get a mark for a well communicated answer. Then you follow on with your points. So some people could have set things they look for in the question or set points or just: DPMCV ie Describe Procedure, Measurements, Controls, Variables and so on and so on. Even if you waffle, just structure it well and get a point for a well organised argument. Just a few thoughts could be absolute nonsense though

[thenumber2goose]

(Original post by vVShabbaVv)
Elements of the question. Could be a set plan? Just had my tutor go over this with me. Basically you plan the question first as you can get a mark for a well communicated answer. Then you follow on with your points. So some people could have set things they look for in the question or set points or just: DPMCV ie Describe Procedure, Measurements, Controls, Variables and so on and so on. Even if you waffle, just structure it well and get a point for a well organised argument. Just a few thoughts could be absolute nonsense though

Thanks! Good luck for the exam by the way

[JenniS]

how many ums is this unit worth, I know unit 1 was 120, whats this?

[vVShabbaVv]

(Original post by JenniS)
how many ums is this unit worth, I know unit 1 was 120, whats this?

are they both 120?

[vVShabbaVv]

(Original post by vVShabbaVv)
are they both 120?

yes it is and 60 for unit 3

[Farzyy]

Can someone tell me if this is correct?

For the diffraction grating experiment when white light is used, a diffraction pattern is produced when the light is passed through a slit. The pattern produced has a bright white central maxima because all the frequencies have been let through (known as the 0 order) then either side of the white maxima are continuous spectrum of light with blue nearest the centre, this is because white light is made up of lots of frequencies?

Thanks

[JenniS]

(Original post by vVShabbaVv)
yes it is and 60 for unit 3

thanks

[JenniS]

(Original post by Farzyy)
Can someone tell me if this is correct?

For the diffraction grating experiment when white light is used, a diffraction pattern is produced when the light is passed through a slit. The pattern produced has a bright white central maxima because all the frequencies have been let through (known as the 0 order) then either side of the white maxima are continuous spectrum of light with blue nearest the centre, this is because white light is made up of lots of frequencies?

Thanks

sounds right to me

[fayled]

Anybody got any ideas of experiment questions?

I can think of:
Young's modulus
Hooke's law
Wavelength of light from diffraction grating or double slits

Might do some model answers and post them...

[Farzyy]

(Original post by fayled)
Anybody got any ideas of experiment questions?

I can think of:
Young's modulus
Hooke's law
Wavelength of light from diffraction grating or double slits

Might do some model answers and post them...

Model answers would be good.

[bugsuper]

RE: The experiment questions -- Those are all quite likely, especially calculating the wavelength of light.

Personally I'm hoping for a Young's Modulus one because that's quite easy and I have the answer memorised.

Other ones could include testing the gravitational acceleration of an object;
working out the maximum speed of an object

both of those, you might use a light-gate for and then see if it matched what the theory predicts (accelerating constantly at a rate of g, basically)


Another one I saw on a very old past paper that might still come up is testing the Principle of Moments. The answer to that if I recall was

- meter rule balanced on pivot
- newtonmeter supports the rule at one end
- known weight placed on the other end of the rule
- position of weight shifted, position recorded
- support force provided by newtonmeter also recorded
- as Newtonmeter is a constant distance from the pivot of the rule, (dist x support force) should = (weight position x weight) if the Principle of Moments applies

Unlikely to come up IMO but I may as well share the love

Also, with these experiment questions, I say READ the wording. If it contains any of the words "precision" or "reliability" or "accuracy", they're expecting specific points pertaining to those words.

precision = instruments with a small scale of measurement, ie micrometer instead of rule

reliability = results can be repeated / repeat readings are all similar / no massive errors in experimental procedure. If possible, plotting a graph of a linear relationship --> points conforming closely to line = reliable

Accuracy = closeness to actual value; for example determining the young's modulus using the gradient of a stress-strain graph rather than dividing one value of stress by one value of strain, repeating measurements and finding an average

That way even if the experiment question is diabolically bad you can get 2-3 marks without actually knowing the theory / what's expected of you, I think.

HIH. Now that Maths is over I'm focused on this exam.

[fayled]

I'll post some model answers for the main ones first (i.e YM and HL) then add to them

[fayled]

2 so far...

[fayled]

If anybody has any improvements be sure to say so and I'll edit them

[IAmTheChosenOne]

hey,

I'm confused about
-double slit
-single slit
-diffraction grating
-white light!

They're all confusing. Could someone please explain them to me?

[Farzyy]

(Original post by IAmTheChosenOne)
hey,

I'm confused about
-double slit
-single slit
-diffraction grating
-white light!

They're all confusing. Could someone please explain them to me?

Here's what I know.

When you you pass white light through slits like in a diffraction grating a diffraction pattern is observed, this will consist of a bright white maxima in the centre and sets of the continuous spectrum either side for each order with the blue scale being nearest the middle, I think this is because white light is made up of different frequencies hence the different colours.

But for normal coherent light you just get fringes of bright and dark with the brightest being in the centre like above, the dark bits are where destructive interference has taken place and light is where constructive has taken place.

Also if i light bulb is being used, a single slit is placed infront of the double slit to create a small coherent light soure, as the light from the bulb would work properly as it isnt coherent i think.

Could someone please correct me if i'm wrong.