Recent content by avjt

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    Electric field boundary equation implication at air/earth interface

    If we consider an arbitrary time varying current I\left(t\right) flowing through an arbitrary antenna, then is the following a plausible expression for the electric field \vec{\mathrm{E}}\left(\vec{\mathrm{r}},t\right) in the far field region...
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    Charging an object by friction

    Thanks sambristol. Interesting to know that the charge will be independent of the material the ball is made of. Cheers, Avijit
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    Charging an object by friction

    Hi All. I'm trying to get a quantitative sense of how much charge we can put on an object by rubbing: the 'triboelectric effect'. To put it specifically, suppose I have a sphere of diameter 1 cm, made of thermocol (polystyrene). How much charge, approximately, can I reasonably expect to...
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    Instantaneous power at infinite distance from current element

    Thanks Chris. The problem I seem to be having is that, for the current element {\delta}{\ell} carrying a current I_{0} cos({\omega}t), I get far-field values of \vec{B}=-{\mu}_0 \frac{I_{0}\: {\delta}{\ell}\: sin({\theta})}{4{\pi}}(\frac {\omega} {cr})sin({\omega}t')\hat{\phi} and...
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    Instantaneous power at infinite distance from current element

    Hi all, Consider a 'current element' of length 'dl' carrying a current of I_{0} cos ({\omega}t). I understand the computation of the electric and magnetic fields due to this current element at any point (r, \theta, \phi), the computation of the Poynting vector at that point, and how the...
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