The Physics PHYA2 thread! 5th June 2013

Hoping for a paper most heavily based around waves this time round. Waves I'm absolutely fine with, but I cannot do mechanics for the life of me. About 80% of my lost marks are in the Mechanics section.

Also, anybody done the June 2009 paper? What an absolute piece of satan

this word document is SO useful, pretty much goes through EVERYTHING for PHYA2 ... can't attach it here because file too big, but for anyone struggling or just wants to look at notes .. seriously check this out :

http://getrevising.co.uk/resources/mechanics_materials_and_waves_phya2_revision

Lol yeh i prefer the waves and materials bits but i like the theory behind the mechanics like newtons laws etc and moments its just suvat questions with projectiles that i loose marks on but im getting better at projectiles now lol


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Hoping for a paper most heavily based around waves this time round. Waves I'm absolutely fine with, but I cannot do mechanics for the life of me. About 80% of my lost marks are in the Mechanics section.

Also, anybody done the June 2009 paper? What an absolute piece of satan

June 2009 was the easiest paper! But the grade boundaries were also the highest.

Hey! Remember me? Unit 1? How is it going? How is your revision going? I am already feeling very confident m8. And you will notice that I have helped a lot of people in this thread. If you need any help? As me anytime!

An electron can act as a wave too and diffract, you can find it's wavelength using the de broglie wavelength formula,
lambda = h/mv

... but I don't think you need to know it for this unit

Oh PHEW! But does it act the same as when light is diffracted. I mean by if the wavelength is small then then it would change the fringe spacing accordingly?

So the central red graph represents the diffraction grating?

If so, what does the large blue curve and dotted red curve represent? Young's double slit? Really confused as to what each one is.

Yup, it acts just like your typical wave (remember, wave-particle duality). The wavelength of the electron is dependent on it's velocity (inverse relationship).

You'd have to be told the electrons velocity... but like I said, I don't think it will come up not in the spec for the unit. You may come across it at A2

For refraction, am I right in thinking that light of different wave lengths would be refracted by different amounts?

and if so, why?

Thanks! But I think my nelson thornes is MUCH BETTER!

I cant find the June 2009 paper? please could someone link me? Thanks

here you go

This is jut rough aha:

You'd have two wires of equal length (measured with a ruler) suspended, measuring the diameter of the one you want to determine youngs modulus for with a micrometer, in several places to get an average

You'd have a set of weights to apply a force to the wire you want to determine the Young's modulus for, the other wire is purely for control, due to temperature changes or whatever.

You'd apply different forces and note down the force applied and the extension of the wire, measured with the one I've forgotten the name of, starts with a v maybe? And take a few readings with an average found

Do this for at least 6 forces.

Plot a graph of force on the y axis and extension on the x, should be a straight line.

Young's modulus is (force*original length) / (extension*cross sectionalarea)

You'd find the area using the diameter before and A=(Pi) r^2 for a circle.

The gradient of the graph sorts out the force over extension, so you'd take the gradient, multiply by the original length of the wire, and divide by the cross sectional area

Something like that anyways, there may be more points you need to get in
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Hey! Remember me? Unit 1? How is it going? How is your revision going? I am already feeling very confident m8. And you will notice that I have helped a lot of people in this thread. If you need any help? As me anytime!

For the v were you on about vernea caliber?