Understanding the Direction of Lorentz Force: Equation vs. Rules

In summary: The direction of the Lorentz force, F, is determined using Fleming's Left Hand Rule or the cross product equation. The reason for this is because it's a convention chosen for simplicity in explaining the force direction. There is no physical explanation for why the direction is chosen this way, it's simply a matter of defining the direction of the magnetic field and choosing coordinates to make the equations work.
  • #1
Ferruccio
4
0
Lorentz force is explained or demonstrated using Fleming's Left Hand Rule or the Force equation using cross product.
What I'm trying to ask here is, why is the direction fixed using the Left Hand Rule or the equation? Why is the direction here and not there?

Equation and rules are the easiest way to explain the force direction, but they don't explain why.
 
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  • #2
I have never heard of the left hand rule, but if you are asking why this has the handedness it does, it's all a matter of how we define the direction of the magnetic field.
 
  • #3
Nope, I'm not asking about the determination of direction. I'm asking about why the direction.

Let me rephrase my question, let's say my current, I as my ay, magnetic field, B as my az, why is the force, F as ax? why not F = -ax or some other directions?
 
  • #4
Ferruccio said:
why is the force, F as ax? why not F = -ax

That's what's measured.
 
  • #5
Is there a reason for it, a theory behind, or it is a natural phenomenon which is inexplicable?

A reason for it as in, we can hear sound using ears, because the sound is in human audible range. It's a natural phenomenon too, but a reason to explain why.
 
  • #6
You're creating an effect where there is none. Let's say we cross ay and az and get -ax. Instead of wondering "oh why the negative sign?" we say "we like positive things, so let's switch the direction of the x-axis!" So now ay cross az is ax.

That's all the handedness convention is, we're choosing our axes such that this works out. Nothing mysterious or physical about it. Just choosing coordinates.
 

1. How does the Lorentz force work?

The Lorentz force is a fundamental force in electromagnetism that describes the motion of charged particles in electric and magnetic fields. It states that a charged particle experiences a force when moving through a magnetic field or an electric field.

2. Is the Lorentz force always present?

Yes, the Lorentz force is always present whenever a charged particle is in motion. This force is responsible for many common phenomena, such as the movement of electrons in a wire that generates an electric current.

3. Can the Lorentz force be modified or controlled?

Yes, the strength and direction of the Lorentz force can be modified or controlled by changing the magnetic or electric fields in which the charged particle is moving. This is the basis for many technological applications, such as electric motors and particle accelerators.

4. Is the Lorentz force affected by the speed of the charged particle?

Yes, the Lorentz force is affected by the speed of the charged particle. As the speed of the particle approaches the speed of light, the force becomes stronger and can even lead to phenomena such as relativistic effects.

5. Is the Lorentz force a fundamental force?

Yes, the Lorentz force is considered a fundamental force in electromagnetism, alongside the electric force and the magnetic force. It is described by Maxwell's equations and is a crucial concept in understanding the behavior of charged particles in various physical systems.

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