Electric Problem: Charges Drawn to Uncharged Metal Rod

[Physicsisfun2005]

This is a HW problem for my AP Physics class ...i've been pondering over reasons...but would like some more "educated" input

IF a charged glass rod is held near one end of an insulated uncharged metal rod, electrons are drawn to one end. (basically I'm thinking induction here )

a. Why does the flow of electrons cease? After all, there is an almost inexhaustible supply of them in the metal rod.

b. Does any net electrial force act on the metal rod?

 

[daveed]

well i know b- yeah, there's electrostatic attraction between the rods

 

[Hypercase]

Well the glass rod has a positive charge. So when it is near the metal it attracts the sea of electrons(metallic bonding in a metal can be viewed as nuclei in a sea of electrons.(a crude visualization)).

As the electrons flood to the side nearest to the charged glass rod, a slight -ve charge develops at this end of the metal rod, whereas a slight positive charge develops at the other end. This is induction.

The electrons don't flow continuosly as a -ve charge build up(of strength equal to that of the charge on the glass rod.) and this repels the flow of more electrons.

 

[Physicsisfun2005]

thanks...i was thinking somewhere along the lines of that...somes i either think to deeply or become braindead lol