DC vs Step Change Current: Which Induces More Current?

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Discussion Overview

The discussion revolves around the comparison of current induction in a conductor due to a direct current (DC) of 50V 10A versus a step change in current from 1mA to 3mA. Participants explore the implications of these scenarios in the context of electromagnetic induction, particularly referencing Faraday's and Ampere's laws.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions whether a DC current can induce a voltage in an inductor, citing the equation V=L(δI/δt) where (δI/δt) is zero for DC.
  • Another participant suggests applying Faraday's and Ampere's laws to analyze the situation, although some express uncertainty about having enough information to do so.
  • There is a suggestion that the arrangement involves two parallel wires, prompting questions about the interaction between them when one wire's current changes.
  • Some participants express confusion about the assumptions that can be made given the limited information provided in the original question.
  • Hints are given regarding the nature of the currents, emphasizing that one is DC and the other is time-varying, which may influence the induction process.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the application of electromagnetic laws or the assumptions that can be made based on the information given. There are competing views on whether sufficient details are available to apply the relevant equations.

Contextual Notes

Participants note limitations in the information provided, such as the lack of specifics regarding the arrangement of the wires and the parameters needed to calculate magnetic field strength.

liam1992
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Which can induce more current in a conductor, a DC current of 50V 10A or a step change from 1mA to 3mA?

I thought that in a DC circuit the inductor would not induce a voltage as V=L(δI/δt) where (δI/δt) is 0 for a DC circuit. But then some websites that I have looked at say differently so I'm a bit confused. The question doesn't give me enough information to use any of the equations that I have been taught so could you please tell me how to sove this problem. Thank you.
 
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Try Farady's and Ampere's laws ...
 


rude man said:
Try Farady's and Ampere's laws ...

Surely I don't have enough information to apply either of these laws though
 


The arrangement is of two parallel wires, is it? When the current in one of them matches what you describe, what happens in the other wire? Is that the question?
 


NascentOxygen said:
The arrangement is of two parallel wires, is it? When the current in one of them matches what you describe, what happens in the other wire? Is that the question?

I don't know, that statement is all that I was given so I don't know if I am supposed to make assumptions or not.
 


NascentOxygen said:
The arrangement is of two parallel wires, is it? When the current in one of them matches what you describe, what happens in the other wire? Is that the question?

liam1992 said:
I don't know, that statement is all that I was given so I don't know if I am supposed to make assumptions or not.

Well, with such scanty specifications, maybe you are allowed to wave one wire furiously around in the vicinity of the other https://www.physicsforums.com/images/icons/icon5.gif
 
Last edited by a moderator:


liam1992 said:
Surely I don't have enough information to apply either of these laws though

Ah, but you do!
 


rude man said:
Ah, but you do!

I thought you needed the length of the wire and radius to work out the magnetic field strength and things
 


liam1992 said:
I thought you needed the length of the wire and radius to work out the magnetic field strength and things

Not in this case.

Hint: one's a dc current, one is time-varying. Then think about Messrs. Faraday and Ampere.
 

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