Why is the magnitude of the electric field in a sphere the same?

In summary, the conversation discusses the electric field and its magnitude in a sphere with a positive point charge at its center. The formula for electric flux, dφ = E dA, is mentioned, along with the concept that the electric field is pointing outwards in the direction of dA. It is then stated that the magnitude of the electric field is the same at every point on the sphere due to the same distance from the charge. The formula for electric flux is also simplified to φ = EA. However, there is confusion about how the magnitude of the electric field can be the same at all points, with an example given of the magnitude at r= 0.5R being greater than at r=R. The question of whether the
  • #1
Fontseeker
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I was looking at a sphere that has a positive point charge at the center of a sphere with radius R. Now, I understand that the electric field is pointing outwards (in the direction of dA), so

$$d\phi = EdA$$

However, I am told that since the magnitude electrical field is the same because the distance from the charge is the same at each point, this is true:

$$\phi = EA$$

I don't understand how the magnitude of the electrical field is the same in every point of the sphere. For example, wouldn't the magnitude at r= 0.5R be greater than the magnitude at r=R? How can the magnitude be the same?
 
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  • #2
In the sphere or on the sphere? dA is what?
 

FAQ: Why is the magnitude of the electric field in a sphere the same?

Why is the magnitude of the electric field in a sphere the same at all points?

The magnitude of the electric field in a sphere is the same at all points because the electric field lines emanate radially outward from the center of the sphere. This means that the distance between any two points on the surface of the sphere and the center is the same, resulting in an equal magnitude of the electric field at those points.

How does the size of the sphere affect the magnitude of the electric field?

The size of the sphere does not affect the magnitude of the electric field. As long as the sphere is uniformly charged, the electric field will be the same at all points on the surface, regardless of the size of the sphere.

Why is the electric field inside a charged sphere zero?

The electric field inside a charged sphere is zero because the electric field lines inside the sphere cancel each other out. This is due to the fact that the electric field lines inside the sphere are directed in opposite directions, resulting in a net electric field of zero.

Does the material of the sphere affect the magnitude of the electric field?

No, the material of the sphere does not affect the magnitude of the electric field. The magnitude of the electric field is determined by the charge and distance from the center of the sphere, not the material it is made of.

Can the magnitude of the electric field in a sphere be changed?

Yes, the magnitude of the electric field in a sphere can be changed by altering the charge or the distance from the center of the sphere. Increasing the charge or decreasing the distance will result in a higher magnitude of the electric field, while decreasing the charge or increasing the distance will result in a lower magnitude.

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