Electrical conductivity has an effect while charging by conduction?

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  • #1
kololo
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Homework Statement:
Does electrical conductivity affects only the time taken for two conductors to obtain their resultant charge?
Relevant Equations:
-
I understand that electrical conductivity is a measure of how easily charges are able to move in an object.
During charging by conduction (for conductors), it seems that we simply have to add the charges of both object together and divide by two to obtain the resultant charge of either object. Does electrical conductivity then affects only the time taken for the two conductors to obtain their resultant charge?
 

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  • #2
Drakkith
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To charge an object you need to have an electric current into and through that object, correct? How does the resistance (or conductivity) affect an electric current?
 
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  • #3
DaveE
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"resultant charge", to me, means steady state, or that nothing is changing any more, the system is stable. What can you conclude from that assumption about your problem?
 
  • #4
kololo
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To charge an object you need to have an electric current into and through that object, correct? How does the resistance (or conductivity) affect an electric current?
Thank you for your reply, but I still have some queries.
1653537465478.png

Do you mean to say that when the particles are in contact with each other and when electrons move from A to B, there is electron current from A to B?
Since the current is voltage divided by resistance, the higher the conductivity, the less the resistance, and thus the higher the current. And since current is the rate of flow of charge, a higher current will mean that it will take a shorter time for A and B to obtain 2.5q of charge? Please correct me if I'm wrong.
 
  • #5
Drakkith
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Do you mean to say that when the particles are in contact with each other and when electrons move from A to B, there is electron current from A to B?
Absolutely. Electrons are electric charges after all, and current is defined as the movement of electric charges.

Since the current is voltage divided by resistance, the higher the conductivity, the less the resistance, and thus the higher the current. And since current is the rate of flow of charge, a higher current will mean that it will take a shorter time for A and B to obtain 2.5q of charge? Please correct me if I'm wrong.
That looks correct to me.
 
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  • #6
kololo
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Absolutely. Electrons are electric charges after all, and current is defined as the movement of electric charges.


That looks correct to me.
Alright, I understand now. Thank you!
 
  • #7
Delta2
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BTW I don't think its an easy problem to find a formula for the current that flows when we bring two conductors of different potential in contact , but I agree that the conductivity of the conductors will have a proportional effect to this current. Or the resistivity will have an inversely proportional effect. The reason for this is I think Ohm's law in its differential form $$\mathbf{J}=\sigma\mathbf{E}$$ where it gives us clearly that the current density ##\mathbf{J}## is proportional to the conductivity ##\sigma##.

For a simplified version of this problem, check the following thread
https://www.physicsforums.com/threads/inductance-and-charge-redistribution.988487/

PS. Sorry the above link is for two spherical conductors connected by a coil of inductance L but the solution path would be similar if we assume they are connected by a conductor of ohmic resistance R.
 
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  • #8
kololo
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BTW I don't think its an easy problem to find a formula for the current that flows when we bring two conductors of different potential in contact , but I agree that the conductivity of the conductors will have a proportional effect to this current. Or the resistivity will have an inversely proportional effect. The reason for this is I think Ohm's law in its differential form $$\mathbf{J}=\sigma\mathbf{E}$$ where it gives us clearly that the current density ##\mathbf{J}## is proportional to the conductivity ##\sigma##.

For a simplified version of this problem, check the following thread
https://www.physicsforums.com/threads/inductance-and-charge-redistribution.988487/

PS. Sorry the above link is for two spherical conductors connected by a coil of inductance L but the solution path would be similar if we assume they are connected by a conductor of ohmic resistance R.
Thank you
 

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