vänsterhandregeln

The vänsterhandregeln, meaning "left-hand rule" in Swedish, is a mnemonic device used in physics to determine the direction of the magnetic force on a moving charge or a current-carrying conductor within a magnetic field. It is a simplified application of the Lorentz force law.

The rule is typically illustrated by holding the left hand with the thumb, index finger, and middle finger extended mutually perpendicular to each other. The index finger represents the direction of the magnetic field (conventionally from north to south), the middle finger represents the direction of the conventional current (or the velocity of a positive charge), and the thumb then points in the direction of the magnetic force acting on the conductor or charge.

While the vänsterhandregeln is a useful tool for visualizing and remembering the direction of the force, it's important to note that it applies specifically to negatively charged particles if one were to consider the direction of electron flow. For a positively charged particle, the right-hand rule is typically used, though some conventions adapt the left-hand rule for positive charges as well. The underlying principle is the cross product of the velocity vector and the magnetic field vector, which dictates the force's direction. The vänsterhandregeln is a pedagogical aid to quickly ascertain this direction in common scenarios encountered in electromagnetism.