AQA Physics PHYA5 - 28th June 2016 [Exam Discussion Thread]

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Can someone explain the nuclear radius experiment briefly to me, I don't understand the graph minima at all :frown:

im not sure if someone answered this but basically electrons also have wave-particle duality or whatever so they have a de broglie wavelength if they go fast enough and the graph is showing the diffraction pattern so if you look on the notes on physicsandmathstutor and scroll down youll find a picture on the diffraction pattern and it made much more sense to me after i saw that

Reply 501

splashywill

Original post by Cheesecake Ali

Is it just me that finds electron microscopes in turning point extremely hard to learn cuz it's so boring 😪

Posted from TSR Mobile

-thermionic emission
-magnetic lens - condenses electron been towards sample
-(sample)
-objective lens - deflects and inverts scattered electrons
-(Inverted first image)
-microscopic lens- focuses on centre of first image and inverts into high resolution final image
-(final image)

-limitations
- Thickness of the sample can cause the electron beam to slow down therefore reducing de broglie wavelength and worsening resolution
- uneven thickness of sample can cause different amounts of diffraction for electron beam therefore making the distorting final image.

(I did this mainly for my own revision... but this is pretty much all you need to learn about them)

Reply 502

aksdj

Original post by ReeceFraser

Can someone explain what the avagadro constant is and how to use it?

so the Avogadro's constant is like how many particles in a mole of gas, so if you know how many moles the gas is you can multiply by the constant and u get how many molecules. If you know the nucleon number that is how many molecules are in one gram and then u can find its mass, from the number of molecules and the molar mass. I hope this helps to be honest im not entirely clear on it either

Reply 503

Whizbox

Original post by rory58824

To my surprise, no. In the textbook try question 2(b) on page 195.

(((63.92915 - 30*5.5*10^-4)-(30*1.00728+24*1.00867))*931.5)/64

Is the answer?

(edited 7 years ago)

Reply 504

TajwarC

Original post by C0balt

I'm more ****ed for this exam than I was for every other exam, the problem of this exam being the last one is that I put revision off for this for ages lmao

I think that's the case with everyone lol

Reply 505

rory58824

Original post by Whizbox

((63.92915 - 30*5.5*10^-4)*931.5)/64

Is the answer?

Nearly. After calculating 63.92915 - 30*5.5*10^-4, you need to find the mass difference. Then you can calculate the binding energy per nucleon. But the initial calculation is fine.

Reply 506

Whizbox

Original post by rory58824

Nearly. After calculating 63.92915 - 30*5.5*10^-4, you need to find the mass difference. Then you can calculate the binding energy per nucleon. But the initial calculation is fine.

Realised that the second i pressed reply and my internet stopped so wouldn't let me edit it, thanks

Reply 507

Protoxylic

Original post by ReeceFraser

Can someone explain what the avagadro constant is and how to use it?

A measure for how many objects are in a mole of objects. A mole and avagadro's constant are just measurements for things (doesn't have to be atoms). In this case, you use avagadro's number to convert between atoms and moles.

So number of moles = number of atoms/avagadro's constant

Reply 508

ViKZZ

Any predictions for the 6 markers (Thermal/Nuclear and Astrophysics)

Reply 509

WillRose

Original post by ViKZZ

Any predictions for the 6 markers (Thermal/Nuclear and Astrophysics)

i reckon formation of stars for astro, never come up and huge bit of the textbook

Reply 510

C0balt

Original post by TajwarC

I think that's the case with everyone lol

I was like "oh it's fine it's two months away" and now quickly "well **** it's tomorrow fml"

Reply 511

Ac19951

Can someone briefly explain an experiment to determine the Specific heat capacity? Including how to get it from a graphical solution.

Im not entirely sure how I would go about it and its not mentioned in the text books.

Something along the lines of using a heater of a known Power(W) & stopwatch to work out energy(J) and recording temperature at different times..? Will plotting a graph of Q against T give you a gradient of mc?(Q=mc.(delta)T)