3 questions about electricity

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In summary: The battery produces an electric field because the negative and positive terminals are connected by a wire. When you put a battery in someone's phone, it creates a small electric field because the wire is sending a current through it. If you were to put the battery in the other direction, the electric field would push the electrons away from the positive terminal and towards the negative terminal. You need to do work against the electric field to move the electrons in the other direction.
  • #1
user111_23
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This will be my last electricity topic for a while.

1. If an electron is "ejected" by the anode of the battery with voltage, in which form of energy has the electron gained? Kinetic Energy or Potential Energy? If it's Potential Energy, how could you physically describe it? I can tell a fast moving electron has a lot of Kinetic Energy because It's moving fast. But how can I describe the Potential Energy of an electron?

2. In circuits, how is voltage related to the electric field? Why must work be done against the electric field? Does the battery have an electric field? If so, what is the direction of it? Is it from negative to positive or vice versa?

3. How come only moving charge produces a magnetic field?
 
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Sigh...37 looks...No replies. What is wrong with my post? :uhh:
 
  • #3
You're too impatient, that's what's wrong :wink: 37 views is nothing to get worried about.
user111_23 said:
This will be my last electricity topic for a while.

1. If an electron is "ejected" by the anode of the battery with voltage, in which form of energy has the electron gained? Kinetic Energy or Potential Energy? If it's Potential Energy, how could you physically describe it? I can tell a fast moving electron has a lot of Kinetic Energy because It's moving fast. But how can I describe the Potential Energy of an electron?

2. In circuits, how is voltage related to the electric field? Why must work be done against the electric field? Does the battery have an electric field? If so, what is the direction of it? Is it from negative to positive or vice versa?

3. How come only moving charge produces a magnetic field?
1. An electron that leaves the negative terminal of a battery won't be moving at high velocity right away, so that rules out kinetic energy. It has electrical potential energy. And there is no physical description of potential energy that corresponds to "it's moving fast" for kinetic energy. The best you can do is note that the electron will be pulled toward a region where it would have lower potential energy.

2. The electric field is the gradient of voltage - that is, electric field is how much the voltage changes per unit distance. An electric field tries to push charges in some direction, so if you want to move the charges in the other direction, you need to do work to overcome the electric field's push. A battery does produce an electric field, and I believe it goes from positive to negative, as electric fields always do.

3. That's just the way the world works. Why would you think a stationary charge should produce a magnetic field? You could perhaps try to go with the relativistic explanation, in which a magnetic field is produced by relativistic transformations of the electric field (kind of like time dilation and length contraction), but that could just as easily become really confusing.
 
  • #4
diazona said:
2. The electric field is the gradient of voltage - that is, electric field is how much the voltage changes per unit distance. An electric field tries to push charges in some direction, so if you want to move the charges in the other direction, you need to do work to overcome the electric field's push. A battery does produce an electric field, and I believe it goes from positive to negative, as electric fields always do.

How does a battery produce an electric field though? And if electrons go from negative to positive, then why do you need to do work against the electric field going from positive to negative?
 

What is electricity?

Electricity is the flow of electric charge through a conductor, such as a wire. It is a form of energy that powers many of the devices and machines we use in our daily lives.

How is electricity generated?

Electricity can be generated in various ways, including through the use of fossil fuels, nuclear power, and renewable sources such as wind and solar. These sources are used to spin turbines, which then produce electricity through a generator.

What are the different types of electricity?

The two main types of electricity are direct current (DC) and alternating current (AC). DC flows in one direction and is commonly used in batteries, while AC alternates in direction and is used in most household electrical outlets.

What are conductors and insulators?

Conductors are materials that allow electricity to flow through them easily, such as metals. Insulators, on the other hand, do not allow electricity to flow through them easily and are used to prevent electrical currents from passing through certain areas.

What are the dangers of electricity?

Electricity can be dangerous if not handled properly. It can cause electrical shocks, fires, and even death. It is important to follow safety precautions when working with or near electricity, such as wearing protective gear and using insulated tools.

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