Physics Help Forum Maxwell's law

 Electricity and Magnetism Electricity and Magnetism Physics Help Forum

Apr 27th 2017, 02:16 AM   #11
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Location: New Zealand
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 Originally Posted by harve Can you find a formula giving the wavelength(λ) as a function of amperage(I) and induction(L)?
Isn't one wavelength produced by one circuit of the electrons around the coil? I'm a rank amateur at this but I've seen videos of electrons producing waves on youtube. see this video

I would be interested in what the more seasoned physicists have to say but I would guess that the wavelength would be the reciprocal of the electrons per seconds around a coil which would depend on the diameter of the coil and the speed of the electrons.

 Apr 27th 2017, 06:04 AM #12 Physics Team     Join Date: Jun 2010 Location: Naperville, IL USA Posts: 2,171 The frequency of radiation emitted by an oscillating electron is equal to its frequency of oscillation. For a simple L-C circuit (inductor and capacitor) that frequency is given by: $\displaystyle f = \frac 1 {2 \pi \sqrt {LC}}$ where L is the value of the inductance in henries and C is associated capacitor in farads. See: https://en.wikipedia.org/wiki/LC_circuit The value of L for an air-core tightly wind coil with small gauge wire is: $\displaystyle L = \frac 1 l \mu_0 N^2 A$ where $\displaystyle l$ is the length of the coil, $\displaystyle \mu_0$ is the permeability of free space, which is $\displaystyle \mu_0= 4 \pi \times 10^{-7} H/m$, N is the number of turns of the coil, and A is the cross-sectional area of the coil. Note that neither current nor speed of the electrons has anything to do with this. In fact, the speed of electron flow in a typical electronic circuit like this is really quite small: around 0.002 m/s. Hence radiation due to the electron's circular motion about the coil (known as Synchrotron Radiation) is negligible. Last edited by ChipB; Apr 27th 2017 at 06:09 AM.
May 4th 2017, 01:05 AM   #13
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superconducting

 Originally Posted by ChipB Note that neither current nor speed of the electrons has anything to do with this. In fact, the speed of electron flow in a typical electronic circuit like this is really quite small: around 0.002 m/s. Hence radiation due to the electron's circular motion about the coil (known as Synchrotron Radiation) is negligible.