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  #1  
Old 01-26-2005, 03:20 PM
EliteNinja EliteNinja is offline
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Default Electron velocity question

Given a certain potential (voltage) applied to an electron, how do you find it's velocity knowing it's charge?

Help me do my homework.
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  #2  
Old 01-26-2005, 03:49 PM
Sweaburg Sweaburg is offline
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Default Re: Electron velocity question

1 Volt = 1 Joule/Coulomb so an electron falling through a potential of 1 Volt will pick up kinetic energy of 1 Joule per Coulomb:

Ek=1/2*me*v^2= qe*V

me and qe are electron mass and charge.
V is potential difference.
v is velocity.

E&M kicks ass.

Good luck...
Randy
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  #3  
Old 01-26-2005, 04:12 PM
daryn daryn is offline
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Default Re: Electron velocity question

ding.


that is if the entire potential energy goes into kinetic though. you could also find the coulomb force and calculate the acceleration so you could then use kinematics to solve for v(t).
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  #4  
Old 01-26-2005, 04:15 PM
Paluka Paluka is offline
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Default Re: Electron velocity question

It is pathetic how little of my applied physics education I remember. Magic: the Gathering turned me into a useless gamer.
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  #5  
Old 01-26-2005, 04:15 PM
Duke Duke is offline
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Default Re: Electron velocity question

[ QUOTE ]
you could also find the coulomb force and calculate the acceleration so you could then use kinematics to solve for v(t).

[/ QUOTE ]

Bonus points if you then tell me precisely where the electron is.

~D
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  #6  
Old 01-26-2005, 04:15 PM
daryn daryn is offline
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Default Re: Electron velocity question

booooooooo [img]/images/graemlins/laugh.gif[/img]
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  #7  
Old 01-26-2005, 06:10 PM
wacki wacki is offline
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Default Re: Electron velocity question

I'm suprised nobody has talked about electron drift which is totally different than electron speed. I would think that most people would easily reverse the two.

FYI, for a copper wire of radius of 1 mm carrying a current of 10 Amps, the drift velocity (velocity the electron travels down the wire) is only a very slow 0.024 cm/sec.

That same electron is traveling about c/3 around the copper atoms though.
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  #8  
Old 01-26-2005, 06:13 PM
bonanz bonanz is offline
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Default Re: Electron velocity question

do you ever make a post that does not draw attention to the fact that you are an engineering student?
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  #9  
Old 01-26-2005, 06:14 PM
daryn daryn is offline
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Default Re: Electron velocity question

</font><blockquote><font class="small">In risposta di:</font><hr />
I'm suprised nobody has talked about electron drift which is totally different than electron speed. I would think that most people would easily reverse the two.

FYI, for a copper wire of radius of 1 mm carrying a current of 10 Amps, the drift velocity (velocity the electron travels down the wire) is only a very slow 0.024 cm/sec.

That same electron is traveling about c/3 around the copper atoms though.

[/ QUOTE ]


bah, nobody who's anybody confuses drift velocity with velocity.
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  #10  
Old 01-26-2005, 06:29 PM
Sweaburg Sweaburg is offline
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Default Re: Electron velocity question

[ QUOTE ]
[ QUOTE ]
I'm suprised nobody has talked about electron drift which is totally different than electron speed. I would think that most people would easily reverse the two.

FYI, for a copper wire of radius of 1 mm carrying a current of 10 Amps, the drift velocity (velocity the electron travels down the wire) is only a very slow 0.024 cm/sec.

That same electron is traveling about c/3 around the copper atoms though.

[/ QUOTE ]


bah, nobody who's anybody confuses drift velocity with velocity.

[/ QUOTE ]

Word. Drift only occurs in a conductive medium and given the basic nature of the original question I'm pretty confident we're working in a vacuum here.

Keep It Simple Stupid

R.
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