A metal rod moving thru a magnetic field

In summary, a discussion takes place regarding the voltage generated in a metal rod moving through a magnetic field. The formula for the voltage is given, but there is confusion about why the voltage exists when the magnetic flux does not change. Further discussion involves the direction of the current inside the circuit and the eventual constant speed of the rod to the right. There is also mention of Lenz's rule and the potential impact on the rod's movement. The person involved is seeking help for an upcoming exam.
  • #1
Nikitin
735
27
Hi. A metal rod is moving thru a homogeneous magnetic field, standing 90 degrees upon it and the movement direction.

Supposedly there is a voltage between the two ends of the rod due to the moving. But why? The magnetic flux doesn't change!

I know that the voltage is supposed to be W/Q = vBq*L/q where L is the length of the rod, but still isn't faraday's law of induction (generated voltage = flux change) broken?

See the uploaded picture for further info
 

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  • #2
Check the picture inside the attached word-file.

A rod lies frictionless on two rails. When the circuit is opened the rod starts moving to the right by itself. What is the direction of the current inside the circuit?

I say it's against the clock, and the magnetic field tries to counteract it and change the direction of the current. The book says it's with the clock, and the magnetic field tries to counteract it.

Why am I wrong?

Additionally, the book claims that rod will eventually get a constant speed to the right. Why? That means the magnetic flux is constantly increasing, and according to Lenz's rule the rod should eventually STOP, not keep going!
 

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  • #3
Help? I've got exams on Tuesday, I really need help
 

Related to A metal rod moving thru a magnetic field

1. What is the relationship between a metal rod and a magnetic field?

A metal rod moving through a magnetic field creates an electric current in the rod, known as electromagnetic induction. This is due to the interaction between the magnetic field and the free electrons in the metal.

2. How does the speed of the metal rod affect the electric current produced?

The faster the metal rod moves through the magnetic field, the greater the electric current that is produced. This is because the rate of change of the magnetic field is higher, resulting in a stronger induced current.

3. Does the strength of the magnetic field impact the electric current in the metal rod?

Yes, a stronger magnetic field will result in a greater electric current being induced in the metal rod. This is because a stronger magnetic field will cause a larger force on the free electrons in the metal, resulting in a stronger electric current.

4. How is the direction of the electric current determined in a metal rod moving through a magnetic field?

The direction of the electric current is determined by the right-hand rule. If the thumb of the right hand points in the direction of the metal rod's motion, and the fingers point in the direction of the magnetic field, then the palm will face in the direction of the induced current.

5. Can a metal rod's movement through a magnetic field be used to generate electricity?

Yes, the process of electromagnetic induction can be used to generate electricity. This is how most generators, such as those used in power plants, work. By rotating a coil of wire through a magnetic field, an electric current is induced, which can then be harnessed for various purposes.

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