Recent content by smileandbehappy

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    Admissions What should I wear to my PhD interview?

    Europe actually UK. I've sent loads of emails and have even had a couple of phone interviews. They are discussing starting dates and funding so I guess that's positive. I get the feeling they are more desperate to not lose the funding rather than them being blown away by my intellectual...
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    Admissions What should I wear to my PhD interview?

    Anyone willing to offer any advice? I have a PhD interview soon and wanted to know what I should ask/do in it? I have a reasonable comprehension of what the project is about - I have some relevant work experience in the area. I would usually wear a suit but I've never seen a lecturer in one so...
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    What Is the Upper Limit for Hertzian Dipole Dimensions?

    Maybe my answer isn't as ridiculous as it seems... Any idea about how I would go about answering the second part? It has to be related to Rayleigh scattering... But apart from that gem of knowledge I have absolutely no idea.
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    What Is the Upper Limit for Hertzian Dipole Dimensions?

    You are correct that is not what I meant... I missed out some brackets. Apologies for that. The calculation should have been: (3*10^8)/(300*10^3) = 1000m So what am I doing wrong? 1km Hertzian Dipole is not normal in my limited experience.
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    What Is the Upper Limit for Hertzian Dipole Dimensions?

    Homework Statement A Hertzian dipole is short compared with the wavelength of the radiation it emits. It describes ’short’ radio antennas and the scattering of electromagnetic radiation by small particles. (a) Give an upper limit for the length of a Hertzian dipole antenna operating at 300 kHz...
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    Can I get help with a car speed question? (to fight a traffic ticket)

    It depends on how much force was driving the car doesn't it... :) Do you mean how much the car could decelerate? If you take gravity and use some right angled triangles you can work that out simply enough. If you mean other things then you don't have enough information. How much a car would...
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    Finding energy from dipole moment - Helmholtz pair?

    I though ti was 90 degrees. But I am guessing I am wrong...
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    Finding energy from dipole moment - Helmholtz pair?

    The sign shoud be: U = -B.m So I still get a minus sign... Or am I missing something obvious? Should I just double the U and make it positive to get the answer?
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    Finding energy from dipole moment - Helmholtz pair?

    Firstly apologies for not typing this out - but I need the diagram. And I have no idea where to start. I 'think' most of it is correct. BUT - I have no idea what to do with the last part of c. I thought I could just double the energy. But I'm going to get a negative energy for the system...
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    Ampere's Law - finding Magnetic Field

    Actually that's one of the best posts I've got on here. I'd rather people were brutal. e(phi) should be unit vector. μ should be inside the conductor - although I'm unsure if it should be just μ or μμ_o
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    Ampere's Law - finding Magnetic Field

    Sorry guys - I was being silly. I have posted what I think is the correct answer... But I might be completely stupid here. Also apologies for not typing it. I needed the diagram to understand it... Let me know if I'm being completely stupid and it's wrong. Thanks for all those who have...
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    Ampere's Law - finding Magnetic Field

    Sorry I am confused - what is H and what is N?
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    Ampere's Law - finding Magnetic Field

    Homework Statement A long, straight, cylindrical conductor with relative permeability ## \mu ## has a radius a and carries a current I. The current density is uniform. Using Ampere's law in it's integral version, finding the magnetic field B: a) Inside, and b) outside the cylinder. Homework...
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    Potential in parallel plate system from charge density?

    Thanks on both making me see how stupid I am being - and pointing out how I can use latex. I think I am trying to make a lot of this stuff harder than it has to be... Either that or I'm just a bit thick. But I appreciate you helping me out. So all I need to do now is substitute in the expression...
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    Potential in parallel plate system from charge density?

    Here is my problem - I am not doing it properly, or not understanding the question then! I've posted my work below. I can't type that out, as I don't know how to put the differentials in etc... Or the integral signs. But I am not sure how to do get rid of the x. I am failing to understand this...
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