# Electric monopole, dipole of sphere

• m0nk3y
In summary, the conversation discusses how to handle a charge -4q and its effects on a system with two +q charges. There is confusion about whether to ignore the -4q charge and how to calculate its effect on the system. The conversation also mentions the concept of monopole and dipole moments and suggests using these to calculate the overall effect of the charges.

## The Attempt at a Solution

I am not sure what to do with the -4q.(did something with this)
I was thinking of ignoring it, and treating it like if it is really far away, however since it is only twice the distance from the origin as the two +q charges, i am not sure what to do with it.

** Edit
is there a way to add all three charges and calculate how they are felt in the origin?SORRY for posting this twice I was trying to edit,because i added my drawing, and now i don't know how delete the other thread!
Thanks

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Your diagram doesn't seem to be correct. The charge -4q is distributed over a sphere of radius R, so it covers the other two charges. Also, you cannot ignore given charges at your will.

Do you know what is meant by the monopole moment?

Write down the expressions for dipole moments for discrete and continuous charges. You must be knowing the formulae. Then you just have to add the two. If you note the spherical symmetry of the -4q charge distribution, the dipole moment becomes very easy to find.

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## 1. What is an electric monopole?

An electric monopole is a hypothetical point charge that has a single positive or negative charge and no other charges nearby. It is considered a fundamental concept in electromagnetism and is the simplest type of charge distribution.

## 2. What is an electric dipole?

An electric dipole is a pair of equal and opposite point charges that are separated by a small distance. It is considered a fundamental concept in electromagnetism and is often used to model the behavior of polar molecules.

## 3. How does a sphere behave as an electric monopole?

A sphere behaves as an electric monopole when it has a net charge that is evenly distributed throughout its surface. This means that the electric field produced by the sphere is spherically symmetric, with the same strength and direction at all points on its surface.

## 4. How does a sphere behave as an electric dipole?

A sphere behaves as an electric dipole when it has a net charge that is unevenly distributed throughout its surface. This means that the electric field produced by the sphere is not spherically symmetric, and the strength and direction of the field will vary at different points on its surface.

## 5. What are some real-life examples of electric monopoles and dipoles?

An electric monopole can be found in a lightning bolt, where the negatively charged bottom of the cloud creates a positively charged ground. An electric dipole can be found in a water molecule, where the slightly negatively charged oxygen atom and the slightly positively charged hydrogen atoms create an uneven distribution of charge.