OCR PHYSICS B G495~ 18th June 2015 AM ~ A2 Physics

Can anyone explain how this graph is formed, and why it has this shape and why nuclear radius affects where the minimum and maximum occur? All I know is that a minimum forms due to destructive interference of the electrons, acting as waves, with the protons.

Reply 62

Rhetorical Hips

14

Original post by Nikeshp79

Can anyone explain how this graph is formed, and why it has this shape and why nuclear radius affects where the minimum and maximum occur? All I know is that a minimum forms due to destructive interference of the electrons, acting as waves, with the protons.

Nuclear radius changes the spacing between nucleons does it not? Thus changing d will cause theta to change?

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Reply 63

Nikeshp79

Original post by Rhetorical Hips

Nuclear radius changes the spacing between nucleons does it not? Thus changing d will cause theta to change?

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Oh I've not come across that before! Thanks for letting me know :tongue:

However, the electrons don't pass through the nucleus in this experiment right? And it's to do with electrons, acting like a wave, and having a charge passing by a nucleus (electric field) causing the deflection angle to change. I just don't understand how the minima is formed if there is only one beam of electrons.

Reply 64

bafid

1

Original post by Nikeshp79

Oh I've not come across that before! Thanks for letting me know :tongue:

However, the electrons don't pass through the nucleus in this experiment right? And it's to do with electrons, acting like a wave, and having a charge passing by a nucleus (electric field) causing the deflection angle to change. I just don't understand how the minima is formed if there is only one beam of electrons.

Electrons act as a wave, when a wave hits lots of little circles blocking its paths you get diffraction around the edges of circles causing an interference pattern which is it a lot of concentric rings of maxima and minima, the spacing is based on the wavelength of the wave and the diameter of the circles blocking it (diameter of atoms). So you look at sin(theta) for the first minima and take into account the wavelength of the electrons and then you can calculate the radius of a nucleus

Reply 65

Nikeshp79

Original post by bafid

Electrons act as a wave, when a wave hits lots of little circles blocking its paths you get diffraction around the edges of circles causing an interference pattern which is it a lot of concentric rings of maxima and minima, the spacing is based on the wavelength of the wave and the diameter of the circles blocking it (diameter of atoms). So you look at sin(theta) for the first minima and take into account the wavelength of the electrons and then you can calculate the radius of a nucleus

Excellent, thanks!

Reply 66

ashysmithy105

5

Is it just me or does hardly ANYONE do OCR Physics B? Maybe it's for a reason... :s-smilie:

Reply 67

RealTime

3

Original post by ashysmithy105

Is it just me or does hardly ANYONE do OCR Physics B? Maybe it's for a reason... :s-smilie:

Guess it's one of the harder subjects possibly by a fair bit, and quite a few drop out after AS

Reply 68

username1200599

12

Tomorrow gonna spend the whole day doing Physics revision. Have a bunch of past papers planned + some lens questions from the G491 stuff for section C. Anyone got any other suggestions as to how to consolidate/improve understanding?

Reply 69

OP

Really worried about this exam
:frown:

I need around 85/100 for an A overall

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Reply 70

RealTime

3

Original post by Mutleybm1996

Really worried about this exam
:frown:

I need around 85/100 for an A overall

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Just stay calm and focused in the exam, don't think about it being the chance you must get right. Just push that all away and take in the information.

I panicked in all my exams except chemistry last year, mainly due to not focusing and wanting to achieve very high marks. In combo with not enough revision, it didn't work out of course :tongue:

Just do your best, nothing more can be asked of you

Reply 71

Robbo54

Original post by Mutleybm1996

Really worried about this exam
:frown:

I need around 85/100 for an A overall

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Keep calm! You can do it, your brain will get you through this :smile:

Reply 72

Tibbz2

13

Original post by ashysmithy105

Is it just me or does hardly ANYONE do OCR Physics B? Maybe it's for a reason... :s-smilie:

It's rubbish course compared to OCR A for example, the textbook is dreadful and the amount of stupid wording is probably where most people lose marks...

Schools probably avoid it for those reasons!

Reply 73

username1200599

12

Just had a look through the Signalling and Images section of AS stuff. There doesn't seem to be that much there we need to know for section C.

Reply 74

OP

Is anyone else using the OCR A textbook to revise?

Does anyone have any tips for the section C? Can they throw anything not in our spec at us? Like the magnification of two lenses and stuff

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Reply 75

OP

Original post by Iridann

Tomorrow gonna spend the whole day doing Physics revision. Have a bunch of past papers planned + some lens questions from the G491 stuff for section C. Anyone got any other suggestions as to how to consolidate/improve understanding?

Just you wait....

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Reply 76

RealTime

3

Original post by Tibbz2

It's rubbish course compared to OCR A for example, the textbook is dreadful and the amount of stupid wording is probably where most people lose marks...

Schools probably avoid it for those reasons!

Yeah the wording is terrible, and the mark scheme can be picky!

Reply 77

OP