# Electric field inside a hollow conductive sphere

• TonyZ
In summary: A metal atom has a filled outer shell and is missing one or more electrons. When an atom loses an electron, it becomes a metal and gains a positive charge.
TonyZ
Hello,
This is my first post to these forums.

It is well known that the electric field inside a conducting
sphere is zero everywhere inside. But what if the charge
placed on the sphere is very, very small. Let's say it
consists of only two electrons. Clearly, this small charge cannot
be evenly distributed on the surface of the sphere. The
two electrons will undoubtedly end up as far apart as possible,
i.e. at opposite sides of the sphere. It doesn't appear that
the electric field is zero everywhere inside this sphere.

I'd like to get the group's input on this.

Thanks!
Tony

A conducting sphere will have many free electrons, and it will be no problem for them to spread evenly.
A charged sphere of copper might consist of 10^24 copper ions and 10^24+2 electrons in the conduction band that can all move around.

The theorems about conductors generally assume a huge number of conduction electrons as willem2 says. If only two electrons are added to a conductor, the lare number of conduction electrons will realign to produce zero field inside. That is, adding two newborns to the world population does not change much, except for their families.

Thanks to all who replied! I understand what you are saying.

I have one other question: Are the "free electrons" in a metalic conductor those which are above and beyond the ones that are part of the metal atoms? For example, copper atoms have 29 electrons and 29 protons. Does having free electrons mean there are more electrons than protons? If so, wouldn't that mean that every metal is inherently
negatively charged (which I know is not correct)?

Thanks,
Tony

Tony

TonyZ said:
I have one other question: Are the "free electrons" in a metalic conductor those which are above and beyond the ones that are part of the metal atoms? For example, copper atoms have 29 electrons and 29 protons. Does having free electrons mean there are more electrons than protons?

There are as many electrons as there are protons. A fraction of the 29 are conducting and the rest are not (valence electrons). I don't know how many of the 29 are valence and how many are conducting, but it should be a well-known constant number at room temperature for copper specialists (probably in a table somewhere, and quite readily calculable with the basic theory).

In condensed matter/solid state theory, a crystal (including a metallic polycrystal) is considered a lattice of (+) ions, through which conducting electrons flow, not a lattice of (neutral) atoms.

## What is an electric field?

An electric field is a physical field that surrounds an electrically charged particle. It is responsible for the electrical force experienced by other charged particles within its vicinity.

## What is a hollow conductive sphere?

A hollow conductive sphere is a spherical object made of a material that allows electric charges to flow freely through it. It is hollow, meaning it has a empty space inside, and it is conductive, meaning it can conduct electricity.

## Is there an electric field inside a hollow conductive sphere?

No, there is no electric field inside a hollow conductive sphere. This is because the charges within the conductor will redistribute themselves in such a way that the electric field inside the sphere will become zero.

## Why is there no electric field inside a hollow conductive sphere?

There is no electric field inside a hollow conductive sphere because the charges within the conductor will move to the surface of the sphere, creating an opposing electric field that cancels out the original field inside the sphere. This is known as the principle of electrostatic shielding.

## What happens to the electric field outside a hollow conductive sphere?

The electric field outside a hollow conductive sphere remains unchanged. This is because the charges on the surface of the sphere do not affect the electric field outside the conductor. The electric field outside the sphere is determined by the total charge on the sphere and its distance from the center of the sphere.

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