Gauss's Law, Sphere (Electric Field

Click For Summary
SUMMARY

This discussion focuses on applying Gauss's Law to determine the electric field of a charged sphere. For a radius \( r < 1 \), the electric field \( E \) is calculated using the formula \( E = \frac{\rho r}{3 \epsilon_{0} \epsilon_{r}} \), where \( \rho \) is the charge density. The confusion arises regarding the behavior of the electric field for \( r > 1 \), where the charge density is zero, indicating that the electric field should also be zero in that region. The key takeaway is that outside the charged sphere, the electric field does not exist due to the absence of enclosed charge.

PREREQUISITES
  • Understanding of Gauss's Law
  • Familiarity with electric fields and charge density
  • Knowledge of spherical symmetry in electrostatics
  • Basic calculus for evaluating surface integrals
NEXT STEPS
  • Study the implications of Gauss's Law in different geometries
  • Learn about electric field calculations for spherical charge distributions
  • Explore the concept of electric field lines and their behavior around charged objects
  • Investigate the relationship between charge density and electric field strength
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone studying electrostatics, particularly those focusing on Gauss's Law and electric fields in spherical coordinates.

jegues
Messages
1,085
Reaction score
3

Homework Statement



See figure attached.

Homework Equations





The Attempt at a Solution



I'm extremely confused.

For r<1,

The total charge enclosed should always be,

\rho \frac{4}{3\epsilon_{0} \epsilon_{r}} \pi r^{3} = \oint _{S} \vec{E} \cdot \vec{dA} = I

The electric field will disperse radially out of the sphere, in the same direction as \vec{dA} so,

I = E\oint_{S} dA = 4\pi r^{2}E

Thus,

E = \frac{\rho r}{3 \epsilon_{0} \epsilon_{r}}

I'm confused about what is suppose to change in the region r > 1 ?

Can someone explain?
 

Attachments

  • QQZ2010.JPG
    QQZ2010.JPG
    24.6 KB · Views: 484
Physics news on Phys.org
The charge density is zero for r > 1.
 

Similar threads

Replies
6
Views
1K
Replies
10
Views
4K
  • · Replies 30 ·
2
Replies
30
Views
2K
Replies
11
Views
2K
Replies
23
Views
5K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 12 ·
Replies
12
Views
7K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K