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    The Position Operator

    Thanks. I knew that the eigenfunction of position is a delta-function, but I just wanted to understand why the logic I outlined at the start is wrong. I think I understand that from tirrel's post as the position operator means multiply by the variable x, not some constant value, so it doesn't...
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    The Position Operator

    Usually in QM we say that a wavefunction psi is an eigenfunction of some operator if that operator acting on psi gives eigenvalue * psi. The position operator is just "multiply by x". So any psi would seem to fit the above description of an eigenfunction of the position operator with...
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    String Test for Rockets

    "String Test" for Rockets This doesn't slot easily into any of the Physics Forum's categories but I guess it is kinda aerospace engineering... And my uni's space society we make small model rockets, just simple things out of paper and card and a small motor. On the sheet of instructions we...
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    Magnetic Flux Linkage

    I guess what I am really asking is how do you determine what area to integrate over when calculating the flux linkage?
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    Magnetic Flux Linkage

    (N.B. All the following assumes that the magnetic fields are in vacuo). I'm having trouble deciding what flux linkage is (as in Faraday's law etc.). What is the proper definition? My textbook gives the example of a coil moving through a magnetic field, tracing out a cylinder - the flux...
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    Electrode Potentials and Complexing

    OK thanks guys. I think I understand now.
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    Electrode Potentials and Complexing

    The standard electrode potential of a Cu/Cu^2+ half-cell is given as 0.34V. However, the half-cell will only have this electrode potential relative to the hydrogen electrode when the concentration of Cu^2+ ions is 1mol.dm^-3. But won't most of the aqueous Cu^2+ ions form complexes...
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    Unidentified Chemical

    Hmm...even with the acid the solution still ended up forming a precipitate. I just don't know what's happening...
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    Unidentified Chemical

    Oh, I also added some HCl to acidify the solution and help prevent the tin reacting and forming a precipitate.
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    Unidentified Chemical

    I spoke to my chemistry teacher today and he reckoned that the SnCl2 was just old and had hydrolysed in the bottle (forming insoluble tin hydroxide). I re-made the solutions using some better quality SnCl2, so I'll check the solutions again tomorrow to see if anything has precipitated out.
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    Integration Question

    Thanks guys. You've been very helpful.
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    Unidentified Chemical

    Today I was making up some solutions of tin(II) chloride dihydrate (SnCl2.2H2O) and I noticed that an insoluble, yellow chemical had formed at the bottom of the beaker. I have no idea what this could be. I've thought about the possibility that there was an impurity in the tin chloride, but...
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    Integration Question

    I'm stuck half-way through a question where I need to find the integral (with respect to x) of: tan(x/2).(cosec x + cot x)^2 I've tried every method of integration that I know and I can't get it. Is it actually possible to integrate the expression? If it's any help, this problem is part of...
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    Supersymmetric Particles

    What are the relationships between particles and their superpartners, other than that the supersymmetric particles have 1/2 less spin than the 'normal' particles? For example, do the pairs of particles have the same force charges?
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    Existence of Virtual Particles

    As I understand it, according to the Copenhagen interpretation of QM, nothing can be said to exist until it is observed. I have also read that it is impossible to observe virtual particles in an experiment. How is it then that virtual particles can be said to exist?
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