Fleming's hand rule

Fleming’s right-hand rule and left-hand rule

English electrical engineer John Ambrose Fleming gave two hand rules known as fleming’s left-hand rule and fleming’s right-hand rule. These two hand rules are used to determine the direction of force, magnetic field, and current for motor and generator only if the direction of any two parameters are known.

Note**  Fleming’s right-hand rule and fleming’s left-hand rule only point out the direction of the given parameters and not the magnitude of the parameters.

When a current-carrying conductor is placed in a varying magnetic field, a force is acted on a conductor. Fleming’s left-hand rule is used to identify the direction of the force. It applies to motors.

When a conductor is placed in a varying magnetic field, then a current is induced in the conductor. Fleming’s right-hand rule is used to identify the direction of induced current in the conductor. It is generally applicable to generators.

Table of Contents

Fleming’s left-hand rule.

It states that when the thumb, forefinger, and middle finger of the left hand are perpendicular to each other. Then the forefinger denotes the direction of the magnetic field, the middle finger denotes the direction of current flowing in the conductor, and the thumb points out the direction of the force.

fleming's left-hand rule
Fleming’s left-hand rule

That means if a current-carrying conductor is placed in the varying magnetic field then the conductor experiences some force on it. The force exerted on the conductor is perpendicular to both the magnetic field and the direction of the current.

So to find out the direction of the force exerted on the conductor. Position your left hand in such a way that the thumb, the forefinger, and the middle finger all are perpendicular ( at 90 degrees) to each other.

Where,

Your forefinger represents the direction of the magnetic field.

Your middle finger represents the direction of current flowing

And your thumb denotes the direction of the force.

Fleming’s right-hand rule

It states that when the thumb, forefinger, and middle finger of your right is perpendicular to each other. Then the thumb represents the direction of force, the forefinger represents the direction of the magnetic field, and the middle finger represents the direction of induced current on the conductor.

Let’s understand this in detail

fleming's right-hand rule
Fleming’s right-hand rule

When a conductor is placed in a magnetic field, a current will be induced in the conductor ( due to faraday’s law of electromagnetic induction).

Then you can find out the direction of induced current on the conductor using Fleming’s right-hand rule.

By Positioning your thumb, forefinger, and middle finger of your right-hand perpendicular (at 90 degrees) to each other.

Where,

Thumb = it represents the direction of motion of the conductor

Forefinger = it represents the direction of magnetic field

Middle finger = it represents the direction of induced current

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