Electric Flux

  • Thread starter brushman
  • Start date
  • #1
114
1
I under stand that electric flux is proportional to the charged enclosed but I don't get why.

Homework Statement


Consider the sphere with the charged enclosed:
[PLAIN]http://electron9.phys.utk.edu/phys136d/modules/m4/images/Image985a.gif [Broken]

As you can see the area and electric field vectors are always parallel.

Now compare that situation to one exactly the same except the charge is moved towards the edge of the sphere (but still inside).

In the first situation the area and electric field are parallel to each other so will have the max value. In the second situation the angle is not always 0 degrees.

How can situation two have the same electric flux when it has smaller angles?

Homework Equations


flux = E dot A



Thanks
 
Last edited by a moderator:

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
25,832
251
hi brushman! :smile:

the flux is ∫∫ E.dA

that is the same as ∫∫∫ ∇.E dxdydz

and ∇.E = 0 in empty space …

so draw a small imaginary sphere with the charge as its centre … the flux through the surfaces of both spheres must be the same (since there's no charge between them) :wink:
 

Related Threads on Electric Flux

Replies
4
Views
723
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
2
Views
744
  • Last Post
Replies
3
Views
916
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
1
Views
1K
Top