Electrical conductivity has an effect while charging by conduction?

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Homework Help Overview

The discussion revolves around the effects of electrical conductivity during the process of charging by conduction, particularly focusing on how conductivity influences the movement of charges between conductors. Participants explore the relationship between conductivity, resistance, and electric current in this context.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the definition of electrical conductivity and its role in charge movement. Questions arise about the relationship between current, resistance, and conductivity, particularly in the context of charging two conductors. Some participants express uncertainty about the implications of their assumptions regarding steady state and current flow.

Discussion Status

There is an ongoing exploration of how conductivity affects the charging process, with some participants providing insights into the relationship between current and resistance. Guidance has been offered regarding the definitions and implications of current flow, but multiple interpretations and questions remain open for further discussion.

Contextual Notes

Participants note the complexity of deriving a formula for current in this scenario and mention the potential influence of different conductor properties on the charging process. There is also a reference to Ohm's law and its relevance to the discussion.

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
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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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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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"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?
 
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Drakkith said:
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.
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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?
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.
 
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kololo said:
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.

kololo said:
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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Drakkith said:
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!
 
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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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Delta2 said:
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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