# Question concerning Electromagnetism

• Shinster007
In summary, the conversation discusses a homework question about a copper ball with a net charge and the fraction of electrons that have been removed from it. The conversation mentions the need for stoichiometry and references to other scientific measurements and concepts. The old definition of coulombs is mentioned as a possible method for solving the question.
Shinster007
Here is a homework question that I have for my general physics class; our professor ran out of time during lecture and did not get to explain the material very well so I am a little lost.

A 47.0 g ball of copper has a net charge of 1.7 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)

I know that it is going to involve some stoichiometry-type solving, but I just can't seem to figure it out

How many electrons does the ball have when not charged?

Yes, you will have to check out what a coulomb is in terms of 'elementary charges' (which is best to look on Wiki because of the relations to other things you'll find there, and look also for ampere) and revise what mole and atomic mass mean.

In my day mnyah mynah the calculation would have been a bit more direct because then the coulomb was defined in terms of electrochemical measurements, the amount of silver deposited by the flow of current in silver nitrate, something very acceptably precisely measurable, so the given number of coulombs $\equiv$ a number of moles of Ag $\equiv$ half that number of moles of Cu considering the atomic charges.

That old definition has been superseded because even more precisely measurable standards have been evolved but it would still be good enough for the calculation asked here.

## 1. What is Electromagnetism?

Electromagnetism is a branch of physics that deals with the study of interactions between electrically charged particles. It encompasses both electricity and magnetism as different aspects of the same fundamental force.

## 2. How does Electromagnetism work?

Electromagnetism works through the interactions between electric charges and magnetic fields. When an electric charge moves, it creates a magnetic field, and when a magnetic field changes, it creates an electric field. These two fields are intertwined and can influence each other, resulting in various phenomena such as electricity, magnetism, and electromagnetic radiation.

## 3. What are the applications of Electromagnetism?

Electromagnetism has a wide range of applications in our daily lives, including electricity generation, communication technology, transportation, and medical imaging. It is also essential in the functioning of electronic devices such as computers and smartphones.

## 4. What is the role of Electromagnetism in the universe?

Electromagnetism plays a crucial role in the functioning of the universe. It is the force that holds atoms and molecules together, allowing for the formation of matter. It also governs the behavior of charged particles in celestial bodies, such as stars and planets, and is responsible for various phenomena in space, such as auroras and solar flares.

## 5. How is Electromagnetism related to other fundamental forces?

Electromagnetism is one of the four fundamental forces in the universe, along with gravity, strong nuclear force, and weak nuclear force. It is related to the other forces through the unification of these forces in the Grand Unified Theory, which is still a subject of ongoing research in theoretical physics.

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