Which Rule is Correct for Determining the Direction of Lorentz Force?

In summary, there are two commonly used rules for determining the direction of magnetic force. The left hand rule involves the index finger representing velocity, the middle finger representing magnetic field, and the thumb pointing towards force. The right hand rule involves the index finger representing the charge's velocity, the middle finger representing the magnetic field, and the thumb pointing in the direction of the magnetic force. Both of these rules can be used for determining the direction of Lorentz force, but the right hand rule is generally preferred. The left hand rule is typically used for determining the direction of induced current in a conductor placed in a magnetic field. However, there may be variations in how these rules are taught and it is important to compare and understand them correctly.
  • #1
physicsmaths1613
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Generally we use the left hand rule - (if index finger shows velocity, middle finger shows magnetic field, the thumb points towards force). Recently I also came across a left hand rule for lorentz force- Using your right-hand: point your index finger in the direction of the charge's velocity, v, (recall conventional current). Point your middle finger in the direction of the magnetic field, B.

Your thumb now points in the direction of the magnetic force. Generally left hand rule is used for determining the direction of induced current in a conductor placed in a magnetic field. Are both of these rules given above correct?Can we use any of them for determining the direction of lorentz force?
 
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  • #2
Are both of these rules given above correct?
... why don't you compare them and see?
 
  • #3
physicsmaths1613 said:
Generally we use the left hand rule - (if index finger shows velocity, middle finger shows magnetic field, the thumb points towards force). Recently I also came across a left hand rule for lorentz force- Using your right-hand: point your index finger in the direction of the charge's velocity, v, (recall conventional current). Point your middle finger in the direction of the magnetic field, B.

Your thumb now points in the direction of the magnetic force. Generally left hand rule is used for determining the direction of induced current in a conductor placed in a magnetic field. Are both of these rules given above correct?Can we use any of them for determining the direction of lorentz force?
I would stick with the right-hand rule and let the signs take care of phenomena such as the direction of induced current in a conductor placed in a magnetic field.
 
  • #4
physicsmaths1613 said:
Generally we use the left hand rule - (if index finger shows velocity, middle finger shows magnetic field, the thumb points towards force). Recently I also came across a left hand rule for lorentz force- Using your right-hand: point your index finger in the direction of the charge's velocity, v, (recall conventional current). Point your middle finger in the direction of the magnetic field, B.

Your thumb now points in the direction of the magnetic force. Generally left hand rule is used for determining the direction of induced current in a conductor placed in a magnetic field. Are both of these rules given above correct?Can we use any of them for determining the direction of lorentz force?

I think this is wrong !
First finger is field, middle finger is velocity and thumb is force...I may be wrong !
 
  • #5
This is how I learned it for deflection of a wire in a magnetic field...
First finger is the Field
Second finger is the Current
Thumb is the movement

So for force on a charge, current is the same direction as the velocity of a positive charge (reverse for negative charges)
The thumb becomes the force.
 
  • #6
Simon Bridge said:
This is how I learned it for deflection of a wire in a magnetic field...
First finger is the Field
Second finger is the Current
Thumb is the movement

So for force on a charge, current is the same direction as the velocity of a positive charge (reverse for negative charges)
The thumb becomes the force.

I agree..I was not wrong
 

FAQ: Which Rule is Correct for Determining the Direction of Lorentz Force?

What is the direction of the Lorentz force?

The Lorentz force is a vector quantity that describes the force experienced by a charged particle moving through an electric and magnetic field. Its direction is perpendicular to both the direction of the magnetic field and the direction of the velocity of the charged particle.

How is the direction of the Lorentz force determined?

The direction of the Lorentz force is determined by using the right-hand rule. If the index finger of your right hand points in the direction of the magnetic field, and your middle finger points in the direction of the charged particle's velocity, then your thumb will point in the direction of the Lorentz force.

Does the direction of the Lorentz force change for positive and negative charges?

Yes, the direction of the Lorentz force will be opposite for positive and negative charges. This is because the force is dependent on the charge of the particle, and opposite charges will experience opposite forces in the same electric and magnetic fields.

How does the direction of the Lorentz force affect the motion of a charged particle?

The direction of the Lorentz force can affect the motion of a charged particle by causing it to change its direction or accelerate. If the Lorentz force is perpendicular to the particle's velocity, it will cause the particle to move in a circular path. If the force is not perpendicular, it will cause the particle to change its direction of motion.

Can the direction of the Lorentz force be reversed?

Yes, the direction of the Lorentz force can be reversed by changing the direction of either the magnetic field or the velocity of the charged particle. However, the force will always be perpendicular to both the magnetic field and the velocity, regardless of their direction.

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