Variation of electric field to produce electric current

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Discussion Overview

The discussion revolves around the relationship between varying electric fields and the production of electric current, referencing Faraday's law of electromagnetic induction and exploring the implications of Lenz's law. Participants examine the conditions under which electric fields can induce current, the role of mobile charges, and the effects of static versus dynamic fields.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that a varying electric field can produce a current, referencing Tesla's electrostatic induction apparatus and questioning the applicability of Lenz's law in this context.
  • Another participant asserts that an electric field will produce a current if there are mobile charges present, emphasizing that a variable field results in a variable current.
  • A participant notes that while a current can flow due to an electric field, it will eventually stop as the system reaches equilibrium, suggesting that continuous change in the electric field is necessary to maintain current flow.
  • Further, a participant questions whether the electric field changes in a circuit with a resistor connected to a battery to sustain a constant current.
  • Another participant clarifies that when a positively charged object is near a conductor, it attracts electrons, and if the object moves, it can induce current by causing the electrons to move as well.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of a varying electric field to maintain current flow, with some arguing that equilibrium halts current while others suggest that a static electric field can still produce current under certain conditions. The discussion remains unresolved regarding the specifics of electric field influence compared to magnetic fields.

Contextual Notes

There are assumptions regarding the behavior of charges in electric fields and the conditions required for current flow that are not fully explored. The discussion also touches on the limitations of Tesla's apparatus and the comparative effectiveness of electric versus magnetic fields in inducing current.

abdo799
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Theoretically , a change in either electric or magnetic field will cause a current to flow , i am already familiar to Faraday's law of electromagnetic induction , so i tried to search about producing a current using a varying electric field, didn't find anything , i found an interseting apparatus though.
http://en.wikisource.org/wiki/Alternate_Current_Electrostatic_Induction_Apparatus
tesla's electrostatic induction apparatus
My question here is about lenz's law , will this law be applicable here ? I know the law is in case of magnets , but i tried to imagine what will happen if we tried the coil magnet situation where approaching coil to the coil a resisting force will develop , but if we replaced the magnet with an electret ( electrostatic equivalent of permanent magnet), as it approaches the loop the side near the electret will obtain a partial charge opposing to charge of the electret causing it to approach faster.
In the end of the article tesla wrote "The output of such an apparatus is very small, but some of the effects peculiar to alternating currents of short periods may be observed. The effects, however, cannot be compared with those obtainable with an induction coil which is operated by an alternate current machine of high frequency, some of which were described by me a short while ago." why will the output of such an apparatus was small ? does electric field has smaller influence on electrons than magnetic field?
 
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An electric field will produce a current if there are mobile charges. It's enough to put a conductor in the field and you get a current. A variable field will produce a variable current. But you don't need a variable electric field to have a current or some "exotic" effects.
 
nasu said:
An electric field will produce a current if there are mobile charges. It's enough to put a conductor in the field and you get a current. A variable field will produce a variable current. But you don't need a variable electric field to have a current or some "exotic" effects.
i know , but the current will soon stop as it reaches equilibrium , adjusting electronic distributing according to electric field , to keep a current flow , u will need to keep the electric field changing
 
abdo799 said:
i know , but the current will soon stop as it reaches equilibrium , adjusting electronic distributing according to electric field , to keep a current flow , u will need to keep the electric field changing

How about a resistor connected to a battery? Is the electric field changing in order to keep a constant current?
 
nasu said:
How about a resistor connected to a battery? Is the electric field changing in order to keep a constant current?

You don't understand me, read the article, the thing is : when a + charged object is near a conductor, it will attract electrons , when this object moves relative to the conductor the electrons will move with him, creating current
 

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