Why Are Fleming's Left and Right Hand Rules Opposite for Generators?

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In summary, the conversation discusses Fleming's left hand rule and its relationship to Fleming's right hand rule. It is explained that the right hand rule is the mirror image of the standard Lorentz force equation and is used for generators, while the left hand rule is used for electron flow. The question of whether the left hand rule can be used with current in the opposite direction is also raised. The website provided offers more information on this topic.
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gangsta316
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I think I know what Fleming's left hand rule but how does Fleming's right hand rule come about and why is it opposite for generators? Is Fleming's right hand rule just the left hand rule for electron flow (instead of current) or would it be more proper to use the left hand rule in that case but with current in the opposite direction to electron flow? Also, what about this right hand rule?
http://www.physics.ubc.ca/~outreach/phys420/p420_96/reg/rhr_lor.htm
 
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If you look at the standard Lorentz force with your right hand (F = I x B) in a mirror, you get Fleming's left hand rule.
 
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Fleming's left hand rule is a rule used to determine the direction of force acting on a current-carrying wire in a magnetic field. It states that if the thumb, index finger, and middle finger of the left hand are extended and positioned perpendicular to each other, with the index finger pointing in the direction of the magnetic field and the middle finger in the direction of the current, then the thumb will point in the direction of the force acting on the wire.

Fleming's right hand rule, on the other hand, is used to determine the direction of induced current in a conductor moving through a magnetic field. It is essentially the same as the left hand rule, but with the thumb pointing in the direction of the induced current instead of the force.

The reason for the opposite hand rules is due to the convention of representing current and magnetic field. In the left hand rule, the current is represented by the middle finger, which is traditionally associated with the positive direction. In the right hand rule, the current is represented by the thumb, which is associated with the positive direction in mathematics and physics.

In generators, the direction of current is reversed due to the conversion of mechanical energy to electrical energy. This means that the direction of the force acting on the wire is also reversed, hence the use of the right hand rule instead of the left.

In terms of electron flow, it would be more accurate to use the left hand rule but with the direction of current opposite to the direction of electron flow. However, in most cases, it is more common to use the right hand rule as it is easier to visualize and understand.

The right hand rule you have linked is known as the "right hand grip rule" and is used to determine the direction of the magnetic field around a current-carrying wire. It states that if the right hand is wrapped around the wire with the thumb pointing in the direction of the current, then the fingers will curl in the direction of the magnetic field.

In summary, Fleming's left hand rule and right hand rule are both used to determine the direction of forces and currents in magnetic fields, with the difference being the representation of current and the direction of force.
 

What is Fleming's left hand rule?

Fleming's left hand rule is a rule used to determine the direction of a force on a conductor in a magnetic field. It was developed by English physicist John Ambrose Fleming.

How does Fleming's left hand rule work?

According to Fleming's left hand rule, if the first finger points in the direction of the magnetic field, the second finger points in the direction of the current, then the thumb will point in the direction of the force acting on the conductor.

What is the purpose of Fleming's left hand rule?

Fleming's left hand rule is used to determine the direction of a force on a conductor in a magnetic field. It is commonly used in the field of electromagnetism to understand the relationship between electric currents and magnetic fields.

Can Fleming's left hand rule be used for both AC and DC currents?

Yes, Fleming's left hand rule can be used for both alternating current (AC) and direct current (DC) circuits. It is a general rule that applies to any type of conductor in a magnetic field.

Are there any limitations to Fleming's left hand rule?

Fleming's left hand rule is a simplified version of the more complex right hand rule, and it only applies to linear conductors. Additionally, it does not take into account the shape or orientation of the conductor. Therefore, it may not accurately predict the direction of the force in certain situations.

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