Conducting rod through a magnetic field

In summary, the question is why the conducting rod being moved at a constant velocity v by a mechanical force F in a uniform vertical magnetic field with flux density B remains at a constant speed. The answer lies in the fact that as the rod moves through the magnetic field, an emf/current is induced due to a change in magnetic flux. This results in a magnetic force acting in the opposite direction of the mechanical force, but with equal magnitude. According to Newton's First and Second Laws, if the sum of forces acting on an object is equal to zero, the momentum remains constant. Therefore, the constant velocity of the conducting rod in this scenario means that the momentum is also constant.
  • #1
thereddevils
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There is this conducting rod being moved to the right a constant speed v by a mechanical force F along 2 parallel , smooth, and horizontal conductors in a uniform vertical magnetic field of flux density B.

The question is why is the speed constant although its being moved by a force ,F.

Well let me answer that first :

Since the conducting rod is being moved through a magnetic field , there is a change in the magnetic flux , hence an emf/current is being induced in the conductor. Now , from Fleming's left hand rule , there exist a magnetic force acting in opposite direction as the mechanical force but are of the same magnitude since the rod moves in Constant velocity.

Another thought came to me , since F=Fm , the conducting rod should be in equalibrium and shouldn't be moving so how did it move with constant velocity according to the question?
 
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  • #2
Remember Newton's First and Second Laws:

[tex]\Sigma \vec F = \frac{d\vec p}{dt}[/tex]

If [tex]\frac{d\vec p}{dt}=0[/tex], what does that tell us about the momentum, [tex]\vec p=m\vec v[/tex] ? Does it mean that the velocity is 0, or something else?
 

FAQ: Conducting rod through a magnetic field

How does a conducting rod moving through a magnetic field create an electric current?

As the conducting rod moves through the magnetic field, the magnetic field induces a change in the electric field within the rod. This change in the electric field causes electrons to move through the rod, creating an electric current.

Why is the direction of the induced current in a conducting rod perpendicular to both the rod's motion and the magnetic field?

This phenomenon, known as the right-hand rule, is a consequence of the Lorentz force law. The direction of the induced current is always perpendicular to the direction of the magnetic field and the direction of motion of the rod, as determined by the direction of the force on a positive charge moving through the magnetic field.

How does the speed of the conducting rod affect the induced current?

The faster the conducting rod moves through the magnetic field, the greater the change in the electric field and the stronger the induced current. This is because the rate of change of the magnetic field is directly proportional to the speed of the rod.

Can a conducting rod experience a force from a magnetic field?

Yes, a conducting rod can experience a force from a magnetic field if the rod is carrying an electric current. This is known as the motor principle and is the basis for many electric motors and generators.

How can the strength of the magnetic field affect the induced current in a conducting rod?

The strength of the magnetic field directly affects the strength of the induced current. A stronger magnetic field will induce a greater change in the electric field, resulting in a stronger current. This relationship is described by Faraday's law of induction.

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