Why the electric field around a positive charge is always directed away from it?

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Discussion Overview

The discussion centers around the question of why the electric field around a positive charge is always directed away from it, exploring the underlying principles and conventions in electromagnetism.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants reference Gauss's Law to explain that the electric field is directed away from a positive charge, suggesting that the sign is a matter of convention.
  • Others argue that the direction of the electric field is arbitrary and is defined as moving away from positive charges due to convention.
  • One participant mentions that the gravitational field is measured by placing a unit positive charge in the field, leading to a repulsive force that moves away from the charge.
  • Another participant humorously suggests that a repulsive gravitational field could be useful, indicating a playful exploration of the concepts.
  • There is a reiteration that the measurement of the electric field is done in the direction a unit positive charge moves, emphasizing the role of convention in defining the field's direction.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the electric field's direction, with some emphasizing the role of convention while others focus on the physical implications of repulsion. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants note that the direction of the electric field is defined by convention, but the implications of this convention and its relationship to physical forces are debated. There are also references to Gauss's Law and the measurement process that remain open to interpretation.

Sharvina Gungah
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Hello everyone!
My question is: why the electric field around a positive charge is always directed away from it? and why not towards?
 
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Gauss Law says the electric field is directed away from a positive charge. ##\nabla E=\rho##
The sign is convention. Gauss Law could have been, ##\nabla E=-\rho##, and with changes of sign made to ##\rho## and ##J## in the rest of Maxwell's equations and the Lorentz equation of electromagnetic force, it would be just as useful.
 
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Because it is repulsion.

The gravitational field is measured by keeping a unit positive charge in the field. The positive-positive repulsion makes the force away from it.
 
A repulsive gravitational field could be very useful :-)
 
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fireflies said:
Because it is repulsion.

The gravitational field is measured by keeping a unit positive charge in the field. The positive-positive repulsion makes the force away from it.

That's not correct. The direction of the field is completely arbitrary. We denote it as being directed away from positive charges simply because of convention.
 
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Drakkith said:
That's not correct. The direction of the field is completely arbitrary. We denote it as being directed away from positive charges simply because of convention.

Yes, because of convention. I mentioned that in this statement

fireflies said:
The gravitational field is measured by keeping a unit positive charge in the field.

Maybe I should have added that the measurement is done in the direction the unit positive charge (point charge in fact) moves. I meant by "Measurement done"=how we measure it (conventionally)
 
Sharvina Gungah said:
Hello everyone!
My question is: why the electric field around a positive charge is always directed away from it? and why not towards?
Convention . You could consider - we draw electric field lines moving away from +ve charges , and moving towards -ve charges - as given by Faraday .

This is simply convention .
 

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