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In Fleming's Left-Hand Rule, what does the middle finger represent?
Direction of magnetic field
Direction of current
Direction of force
Direction of motion
Direction of current
In Fleming's Left-Hand Rule, the middle finger represents the direction of the electric current in the conductor. This rule is used to determine the direction of force experienced by a current-carrying conductor placed in a magnetic field.
In Fleming's Left-Hand Rule, the middle finger represents the direction of the electric current in the conductor. This rule is used to determine the direction of force experienced by a current-carrying conductor placed in a magnetic field.
Think of holding a toy gun where your index finger points the target (magnetic field), your middle finger pulls the trigger (current flowing), and your thumb kicks back due to recoil (force/motion).
FBI rule: Thumb = Force, Forefinger = Magnetic Field, Middle finger = Current (or Current = I, so FBI - Force, B-field, Current).
F=I(l├ЧB) тАФ Magnetic force on a current-carrying conductor
F=q(v├ЧB) тАФ Lorentz force on a moving charge
When a current-carrying conductor is placed in an external magnetic field, the magnetic field produced by the current interacts with the external magnetic field, generating a Lorentz force. According to Fleming's Left-Hand Rule, if the thumb, forefinger, and middle finger of the left hand are mutually perpendicular, the forefinger points along the magnetic field, the middle finger along the current, and the thumb indicates the direction of motion or force.
Used primarily for electric motors and actuators.
The three fingers must be held at right angles to each other.
Applies to conventional current (positive charge flow).
Provides a quick, intuitive visual method to find force or motion direction without complex vector cross-products.
Only applicable when magnetic field, current, and force are mutually perpendicular.
Electric motors
Moving-coil galvanometer
Loudspeakers
| Feature | Fleming's Left-Hand Rule | Fleming's Right-Hand Rule |
|---|---|---|
Primary Application | Electric Motors (converts electrical energy to mechanical energy) | Electric Generators/Dynamos (converts mechanical energy to electrical energy) |
Given Parameters | Magnetic Field & Current | Magnetic Field & Motion/Force |
Named after British engineer John Ambrose Fleming in the late 19th century.
Option A represents the forefinger, Option C/D represents the thumb.
B is correct тАФ The middle finger of the left hand points in the direction of the conventional electric current.
Do not confuse Left-Hand Rule (Motors - find Force) with Right-Hand Rule (Generators - find Induced Current). Always check whether mechanical work is input or output.
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