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# OCR PHYSICS B G492~ 9rd June 2014~ AS Physics Watch

1. (Original post by emfp21)
I like standing waves apart from one bit - how do you do it when they ask you about one that is say 3 x the fundamental frequency etc?

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I'm not entirely sure what you are asking here as you are being quite brief. However, the fundamental frequency is essentially the lowest resonant frequency. If we are talking about a typical string with a driving oscillator and a node at the other end then the fundamental frequency would occur when the length of the string is half a wavelength. Now, 3 x the fundamental frequency would essentially give you three individual 'loops' on the string and the length of the string would be equal to 1 and a half wavelengths.
2. (Original post by leylascarlatella)
Does anyone have the June 2013 paper for physics B? I need it.
http://matthew-arnold.tmp.synergy-le...20j%202013.pdf

http://matthew-arnold.tmp.synergy-le...une%202013.pdf
3. (Original post by leylascarlatella)
Does anyone have the June 2013 paper for physics B? I need it.
look back at my posts in this thread and you will find one where i have linked a website with section C questions, if you look carefully on the website, you will be able to find the june 2013 paper and mark scheme
4. (Original post by smerkz)
I'm not entirely sure what you are asking here as you are being quite brief. However, the fundamental frequency is essentially the lowest resonant frequency. If we are talking about a typical string with a driving oscillator and a node at the other end then the fundamental frequency would occur when the length of the string is half a wavelength. Now, 3 x the fundamental frequency would essentially give you three individual 'loops' on the string and the length of the string would be equal to 1 and a half wavelengths.
Sorry I would be less brief but I don't really understand it :') don't really know what I dont know haha

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5. (Original post by emfp21)
I like standing waves apart from one bit - how do you do it when they ask you about one that is say 3 x the fundamental frequency etc?

Posted from TSR Mobile
The fundamental frequency is the lowest frequency possible i.e the longest wavelength. This is produced when there are two nodes at either end and one antinode in the middle. If I am not mistaken, then 3x the fundamental frequency is where there is 3 antinodes present. I hope this helps
6. (Original post by emfp21)
Sorry I would be less brief but I don't really understand it :') don't really know what I dont know haha

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I just didn't really know what you were expecting as an answer haha :P. But that pretty much is all there is to it unless you were asked to talk about the fundamental frequency in a wind instrument or an air column because they produce longitudinal standing waves. Basically, if you had an air column with an open end which you placed a source at and the other end was closed then a node would form at the other end and the fundamental frequency would occur when the length of the air column is 1/4 of the wavelength and therefore in this case 3 x the fundamental frequency would be 3/4 wavelengths. Whereas, if both ends of the air column were open then you would get the fundamental frequency when the length of the column is 1/2 the wavelength. In this situation an anti-node will form at each end and there will be a central node.
7. Can some please explain the difference between spread and range? Im not too fond of the section C questions. Quality of measurement seems a bit waffley
8. Can someone help me with young's double slit. Questions like Q5 on Jan 2010. I dont understand how you work out the slit seperation (d) given just the Wavelength, fringe spacing (X) and distance from the screen to the slits(L)? Is there an equation i am missing?
9. Oh and what's resolution? Anyone got a list of key terms and definitions, would be really helpful
10. (Original post by Penguin123ab)
Can someone help me with young's double slit. Questions like Q5 on Jan 2010. I dont understand how you work out the slit seperation (d) given just the Wavelength, fringe spacing (X) and distance from the screen to the slits(L)? Is there an equation i am missing?
Yes X= L x Wavelength divided by slit seperation
11. Can I have some help with Young's Slits as well, as I understand it, there are 2 equations. nlambda=dsintheta and X=Dlambda/d (some people use L instead of D). Which equation do you use for single slit, double slit and diffraction gratings. Currently I think single slit is the one involving X and double slit and diffraction grating both use the one involving sintheta. Some clarification would be appreciated
12. (Original post by shloke123)
Guys, click on the link below and scroll to the bottom, there are questions and answers for predicted section C questions

http://matthew-arnold.tmp.synergy-le...view.php?id=62

Thank you so much for this!
13. (Original post by shloke123)
Yes X= L x Wavelength divided by slit seperation
Ah I see, that works, thanks
14. (Original post by shloke123)
Can I have some help with Young's Slits as well, as I understand it, there are 2 equations. nlambda=dsintheta and X=Dlambda/d (some people use L instead of D). Which equation do you use for single slit, double slit and diffraction gratings. Currently I think single slit is the one involving X and double slit and diffraction grating both use the one involving sintheta. Some clarification would be appreciated

X is the fringe spacing, it says it's used for several fringes, probably the double slit and diffraction grating. nlambda=dsintheta is used in a single slit experiment. I got this from the OCR physics B revision book. Hope this helped to clarify things
15. (Original post by shloke123)
Can I have some help with Young's Slits as well, as I understand it, there are 2 equations. nlambda=dsintheta and X=Dlambda/d (some people use L instead of D). Which equation do you use for single slit, double slit and diffraction gratings. Currently I think single slit is the one involving X and double slit and diffraction grating both use the one involving sintheta. Some clarification would be appreciated
n lambda = d sin(theta) applies for all 3 situations, but (not that you need to know) theta is the angle from the central maxima to the nearest minima in single slit diffraction. For single slit diffraction you only need to know what increases with theta and what decreases with theta.

X = lambda L / d applies only for Young's double slit diffraction as far as I know.
16. (Original post by LimbuRonit)
Does anyone know how to choose the right graph for question like
y axis- energy of photon of electromagnetic radiation
x axis - the frequency of radiation
you just have to think about the equation that links the two things that they want. in your example you would use E=hf, which is directly proportional as h is a constant (plank's constant), so it would be a straight line graph

This is my understanding

Hope this has helped
17. Can some please explain the difference between spread and range? Im not too fond of the section C questions. Quality of measurement seems a bit waffley. Oh and what's resolution? Anyone got a list of key terms and definitions, would be really helpful
18. Could someone please explain how relative velocity works to me? I feel that there must be a certain way of thinking about it that I cannot seem to grasp. Thanks in advance
19. (Original post by Roob77)
Could someone please explain how relative velocity works to me? I feel that there must be a certain way of thinking about it that I cannot seem to grasp. Thanks in advance
All I know is to subtract the observer's velocity from the other :/

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20. (Original post by shloke123)
Can some please explain the difference between spread and range? Im not too fond of the section C questions. Quality of measurement seems a bit waffley. Oh and what's resolution? Anyone got a list of key terms and definitions, would be really helpful
I think spread is half of the range. The resolution is the smallest change an instrument can detect. Hope that helped

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