• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Gauss' Law help

I wonder if i could compute resultant E-fields using Gauss' law and finding the field from the flux. I have a few difficulties, the first is of course, finding the E-field from the flux and the second is regarding the closed surface. how should i choose what surface to use, especially if the question just want me to find the resultant E-field alone? Thanks....
 

OlderDan

Science Advisor
Homework Helper
3,021
1
misogynisticfeminist said:
I wonder if i could compute resultant E-fields using Gauss' law and finding the field from the flux. I have a few difficulties, the first is of course, finding the E-field from the flux and the second is regarding the closed surface. how should i choose what surface to use, especially if the question just want me to find the resultant E-field alone? Thanks....
Gaussian surfaces are chosen based on the known symmetry of the charge distribution. For any spherically symmetric charge distribution, you know that the electric field must be radial with constant magnitude at any specific distance from the center of symmetry, so you use a spherical surface for the Gaussian integral. For a uniform plane of charge, or just outside the surface of a metal, you know the field must point directly away from the surface and be constant at any given distance from it. The Gaussian "pillbox" exploits this symmetry to make the integral trivial to evaluate. Inside a metal, the field must be zero, so a closed surface everywhere within a metal yields a zero Gaussian integral. When there is no symmetry, Gauss' Law is still valid, but not particularly useful.
 

Related Threads for: Gauss' Law help

  • Posted
Replies
0
Views
1K
  • Posted
Replies
7
Views
10K
  • Posted
Replies
5
Views
1K
  • Posted
Replies
1
Views
1K
  • Posted
Replies
20
Views
1K
  • Posted
Replies
3
Views
1K
  • Posted
Replies
4
Views
749
  • Posted
Replies
1
Views
806

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top