Fleming's left-hand rule is a mnemonic device used in physics to determine the direction of the force experienced by a current-carrying conductor when it is placed in a magnetic field. It is particularly useful for understanding the working principle of electric motors.
The rule is applied by holding the thumb, forefinger, and middle finger of the left hand at right angles to each other, as shown in the diagram. Each finger represents a different physical quantity:
- Forefinger: Points in the direction of the magnetic field (from North to South pole).
- Middle finger: Points in the direction of the current (from positive to negative terminal).
- Thumb: Points in the direction of the force or motion experienced by the conductor.
The rule states that if you align your forefinger with the magnetic field and your middle finger with the direction of the current, your thumb will automatically point in the direction of the force acting on the conductor.