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

  • #1
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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  • #2
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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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  • #3
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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.
 
  • #4
CWatters
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A repulsive gravitational field could be very useful :-)
 
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  • #5
Drakkith
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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.
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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  • #6
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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

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)
 
  • #7
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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?
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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