Gauss's law derivation using solid angle

In summary, the conversation discusses the search for a rigorous mathematical derivation of Gauss's Law, specifically using Jackson's proof which involves the concept of solid angles. The individual is unfamiliar with solid angles and requests a clear definition. They also question the validity of the proof and wonder if Stokes' Theorem may be a simpler approach.
  • #1
Sionsd
1
0
So, I was trying to find a rigorous mathematical derivation of gauss's law(please I don't want to hear again any field lines nonsense) and I stumbled upon jackson's proof which uses the solid angle concept and seems a solid enough proof(stupid joke:smile:).The problem is that it's the first time I come in contact with solid angles and I don't get a certain part

Eda=(q/4πε)(1/r^2)cosθda=(q/4πε)dΩWhy
(1/r^2)cosθda=dΩ? (intuitively it makes sense but what is the actual proof)

I'd appreciate if someone gave a clear from zero definition of solid angle

Say we've proven Φ=Qen/ε
if the charge lies outside of the surface how do you prove that the total flux is zero?
Is there a solid angle approach or stoke's theorem is the easiest way?
Forgive me for not using latex it's my first post
 
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  • #2
There is a good derivation in Section 1.4 of Franklin "Classical Electromagnetism".
 

Question 1: What is Gauss's law derivation using solid angle?

Gauss's law is a fundamental law in electromagnetism that relates the electric flux through a closed surface to the charge enclosed within that surface. The derivation of this law using solid angle involves using the concept of solid angle to calculate the flux through a small patch of a closed surface.

Question 2: What is solid angle?

Solid angle is a measure of the size of a cone of rays originating from a point on a surface. It is analogous to how angle measures the size of a circular arc. Solid angle is measured in steradians (sr) and is defined as the area of the spherical surface subtended by the cone divided by the square of the radius of the sphere.

Question 3: Why is solid angle used in Gauss's law derivation?

Solid angle is used because it provides a way to calculate the electric flux through a small patch of a closed surface. This is important because Gauss's law relates the total flux through a closed surface to the charge enclosed within that surface. By using solid angle, we can calculate the flux through each small patch and then integrate to find the total flux.

Question 4: How is solid angle calculated?

The formula for solid angle is Ω = A/r², where Ω is the solid angle, A is the area of the spherical surface, and r is the radius of the sphere. Alternatively, it can also be calculated using the formula Ω = 2π(1-cosθ), where θ is the angle of the cone.

Question 5: Are there any limitations to using solid angle in Gauss's law derivation?

One limitation of using solid angle in Gauss's law derivation is that it assumes a symmetrical charge distribution. This means that the charge must be evenly distributed throughout the closed surface. Additionally, solid angle is only applicable for closed surfaces that are perfectly spherical or have a constant radius of curvature.

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