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EliteNinja
01-26-2005, 03:20 PM
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.

Sweaburg
01-26-2005, 03:49 PM
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

daryn
01-26-2005, 04:12 PM
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).

Paluka
01-26-2005, 04:15 PM
It is pathetic how little of my applied physics education I remember. Magic: the Gathering turned me into a useless gamer.

Duke
01-26-2005, 04:15 PM
[ 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

daryn
01-26-2005, 04:15 PM
booooooooo /images/graemlins/laugh.gif

wacki
01-26-2005, 06:10 PM
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.

bonanz
01-26-2005, 06:13 PM
do you ever make a post that does not draw attention to the fact that you are an engineering student?

daryn
01-26-2005, 06:14 PM
</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.

Sweaburg
01-26-2005, 06:29 PM
[ 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.

Patrick del Poker Grande
01-26-2005, 06:30 PM
Are we all smart now? Okay, let's move on.

wacki
01-26-2005, 06:43 PM
[ QUOTE ]
bah, nobody who's anybody confuses drift velocity with velocity.

[/ QUOTE ]

Hey that's not true, they are the people who pay your bills.

/images/graemlins/grin.gif

Riskwise
01-26-2005, 10:57 PM
[ QUOTE ]
[ 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

[/ QUOTE ]

no one knows precisely because of the "uncertainty theory"
i think it says you can only know where an electron "was", because you cant know both speed and position, only one or the other (quantum leaps?).

wacki
01-26-2005, 11:00 PM
You need to learn how to read more carefully.
Linky (http://forumserver.twoplustwo.com/showthreaded.php?Cat=&amp;Number=1613587&amp;page=0&amp;view=c ollapsed&amp;sb=5&amp;o=14&amp;vc=1)