Electric field with reference to voltage

  • Thread starter Angello90
  • Start date
  • #1
Angello90
65
0
If E=-∇V, does it mean that negative voltage emits positive electric field, and positive v negative ef?
 

Answers and Replies

  • #2
sophiecentaur
Science Advisor
Gold Member
27,599
6,225
It's basically a matter of definition.
I think you can look at it this way: The field between a positive plate and a negative plate is said to be directed towards the negative plate (the direction in which a positive charge would move) but the positive plate has a positive potential with respect to the negative plate i.e. voltage increases in the opposite direction to the direction of the force on a positive charge.
 
  • #3
Angello90
65
0
you see I have this question where youre give an equation for potential deference of 10-5z^2, so E= -10z right?, anyway there is a field on one side of the slab (slab is the material with a charge) and it asks about EF on both sides, ie what is EF on right hand side and left hand side. As a hint there is "watch the sign" statement. So I am really confused o_O
 
  • #4
ZapperZ
Staff Emeritus
Science Advisor
Education Advisor
Insights Author
35,995
4,711
If E=-∇V, does it mean that negative voltage emits positive electric field, and positive v negative ef?

That is not what the Grad means! It is the CHANGE in potential over a distance, i.e. a gradient. In 1 dimension, it is E = -dV/dx.

Zz.
 
  • #5
Angello90
65
0
Yeah and d(10-5z^2)/dz=-10z, am I correct?
 
  • #6
sophiecentaur
Science Advisor
Gold Member
27,599
6,225
Uh?

If you want a simple explanation for the sign, the field points towards the negative side and away from the positive. i.e. a negative slope as distance towards the positive increases - hence the negative sign.
Note. A field isn't "emitted".
 
  • #7
Angello90
65
0
Ok thanks a lot sophiecentaur, and yeah i know field isnt emitted, thats why i used "emitted" not emmited;) thanks guys
 
  • #8
sophiecentaur
Science Advisor
Gold Member
27,599
6,225
Ok thanks a lot sophiecentaur, and yeah i know field isnt emitted, thats why i used "emitted" not emmited;) thanks guys

It was terminology I was referring to - not spelling:wink:
 

Suggested for: Electric field with reference to voltage

Replies
4
Views
300
Replies
14
Views
310
Replies
19
Views
324
Replies
10
Views
259
Replies
3
Views
296
Replies
3
Views
155
  • Last Post
Replies
3
Views
140
Replies
2
Views
212
Replies
44
Views
652
Replies
5
Views
504
Top