- #1

- 8

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I accept the notion that models may call for a smallest indivisible unit, I'm only wondering how we establish that we have indeed located that size. Thanks for commenting..

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- Thread starter ndvcx
- Start date

- #1

- 8

- 0

I accept the notion that models may call for a smallest indivisible unit, I'm only wondering how we establish that we have indeed located that size. Thanks for commenting..

- #2

- 2,967

- 5

[tex]

\left\{\begin{array}{lcl}

\frac{m_{e} v^{2}}{r} & = & \frac{k_{0} e^{2}}{r^{2}} \\

m_{e} v r & = & \hbar

\end{array}\right. \Rightarrow

\left\{\begin{array}{lcl}

v^{2} r & = & \frac{k_{0} e^{2}}{m_{e}} \\

v r & = & \frac{\hbar}{m_{e}}

\end{array}\right.

[/tex]

[tex]

\left\{\begin{array}{lcl}

v & = & \frac{k_{0} e^{2}}{\hbar} \\

r & = & \frac{\hbar^{2}}{m_{e} k_{0} e^{2}}

\end{array}\right.

[/tex]

The period is:

[tex]

T = \frac{2 \pi r}{v} = \frac{1}{4 \pi^{2} c} \frac{(h c)^{3}}{m_{e} c^{2} (k_{0} e^{2})^2} = 1.520 \times 10^{-16} \, \mathrm{s}

[/tex]

This gives a current of:

[tex]

I = \frac{e}{T} = 1.05 \, \mathrm{mA}

[/tex]

- #3

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- #4

- 2,967

- 5

- #5

- 640

- 0

What I don't quite get is, if a single electron flows, is there an observed very small current ?

Current density can be seen as the product of the number of charges and their drift speed:

http://en.wikipedia.org/wiki/Current_density

So according to the first equation in that link, nothing prevents having a single electron going at arbitrary low speed, from which you can easily get an atto-ampere if you want. Current depends on both the number of charges and their drift velocity (itself a function of resistance and voltage in paticular).

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