Edexcel IAL Physics Unit 02- 08 May 2017

I thought it was really good. Except I made a few stupid mistakes. *facepalm*

I thought it was really good. Except I made a few stupid mistakes. *facepalm*

Same! When I opened the paper I was like 🤔okay? Let's keep going
Then the theory was decent but silly upon silly mistakes.
The last question was absolutely atrocious

how did u calculate Emf and r from the graph?
i wasnt sure i did that correct..
and the last question.. what did u write for the protractor part?

Emf is the y intercept so 6V
And r is the magnitude of the gradient, so it's 4, not -4
Around that range for both answers

In the protractor question, it was quite simple
First of all, you use 20 degrees as you angle of incidence, then you use the refractive indexes for both zircon and diamond, get the angle of refraction
It'll be 8.14 and 9.86 (something like that I don't remember exactly)
Then you say
'You won't be able to distinguish, because the division scale on the protractor +-1, so They may overlap
I think if you use +-0.5 in your scale of the protractor and state otherwise, it's still be correct

how did u calculate Emf and r from the graph?
i wasnt sure i did that correct..
and the last question.. what did u write for the protractor part?

i coukldnt do that emf and r question by looking at the graph arghhh

then the emf is fine..
the refractive indexes cant be that high.. the highest is for diamond which is 2.3

Those values aren't the refractive index buddy, those are the angles of refraction

i did some silly mistakes all around...
oh what about the 5 mark frequency sound intensity graph question?

i think i wrote the points all wrong

ooh.. how did u get those values?
thats not what i got..
i did a bit of a different method, using the Pythagoras theorem and some other stuff :/

You have to talk about diffraction, you need to mention the following points
• As the frequency of the sound increases, the intensity is constant for the left ear, but decreases for the right ear
• as the frequency increases, the wavelength decreases
• so the effect of diffraction is reduced
• because diffraction is maximised when the size of the obstacle is approximately the size of the wavelength
• so there's less spreading out of the wave
• so less waves reach the right ear
•causing a decrease in the intensity

so i wont get full marks for that question.. i think...
what about which polarized filter the fisherman should use?

Basically the question said 'using this, would you be able to distinguish between diamond and zircon
So you already have the refractive index
2.4 for diamond and 2 for zircon
You have the angle of incidence which is 20 degrees, you use the snell's law
n=sin I/sin r
You obtain the values of r for both zircon and diamond and compare if you would be able to distinguish or not
They gave you a hint in the question saying a protractor, so your answer needs to be an angle

They said its parallel to the surface of the water, so it's horizontal, so you have to choose A because it's 90 degrees to the plane of polarisation, so the glare is blocked

They said its parallel to the surface of the water, so it's horizontal, so you have to choose A because it's 90 degrees to the plane of polarisation, so the glare is blocked

well.. i used all of that..
and the protractor to measure the refractive angle.. by 90-x..
hmm.. will probably lose those marks.. rest of the paper was fine i think..is there an unofficial MS yet?

yup.. it A..
what do u think of the grade boundaires..
50-55 for an A??

That question bugged me because the position of the man is unknown, who knows if he was standing opposite the wave travel or something

Unofficial marking scheme usually takes a longer time to come out, Dw, the exam wasn't easy, you'll do just fine