Electron accelerating in a bent wire

1. Apr 30, 2015

lirkepirk

If I run a current through a wire with a 90 degree turn, what prevents the electrons from continuing out of the wire is a straight forward path? What force accelerates them in the direction of the wire?

2. Apr 30, 2015

Staff: Mentor

3. Apr 30, 2015

lirkepirk

Thanks a lot!

4. Apr 30, 2015

nasu

Even without current and without a bent, we have the problem of electrons moving with speeds of tens of thousand of m/s through the metal.
Did you ever wondered why they don't get out of the metal?
I am not saying that it's not a good question. Just that is a more general one.

5. Apr 30, 2015

rumborak

On a related note, the average speed of electrons (the http://en.wikipedia.org/wiki/Drift_velocity ) is miniscule. For a 3A current through a 1mm diameter copper wire, the drift velocity is 0.28 mm/s.

6. Apr 30, 2015

davenn

it does happen, but only with very high voltages and currents ( but it's still not a speed of electrons issue)
@rumborak covered that in his last post

When I was in the telecommunications industry, I would very often see this effect on sharp - 90 deg bends in cables that has been struck by lightning
It didn't matter if it was an underground multipair telephone cable, a coaxial cable or a lightning earthing cable on a pole/mast

It was amazing to see how the current from a lightning strike would travel down 100's of metres - several km's of cable in a straight line and then when that cable would do a bend to be spliced into the main trunk cable the current would punch a hole in the apex of the bend and go to ground

Dave

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