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Right-hand rule
What is the right-hand rule for?
The right-hand rule or three-finger rule is an aid that illustrates vectors within a three-dimensional coordinate system. This help is used in different areas of mathematics and physics:
- In the geometry for orientation of a vector or vector point from the cross product of a coordinate system.
- To determine the direction of the angular momentum in the rotation of bodies.
- In physics in the context of electromagnetism and electrical engineering as the cause-mediation-effect rule (UVW rule). It is also described in this context as a corkscrew rule or right-fist rule.
The right-hand rule in physics
In the field of physics, the right-hand rule occurs mainly in the area of a magnetic field. Whenever a current-carrying conductor is exposed to a magnetic field, for example by a horseshoe magnet, a force is exerted on this charge carrier. The reminder illustrates the directions in which forces act on the conductor:
The thumb records the direction of movement of positive charged particles (electrons) in the current direction from + to -. This direction of movement is called voltage (ampere).
The index finger describes the direction of the field lines of the magnetic field from the north to the south pole. By means of the right-hand rule, the polarity of magnetic field lines, ie their direction, can also be determined. The magnetic flux density describes the strength of this field.
In this constellation, the middle finger indicates the force that influences the current-carrying carrier.
It is important that the three fingers are perpendicular to each other according to the direction of the force: Thus, the forces of the magnetic field always act perpendicular to the current-carrying conductor and parallel to it perpendicular to the direction of movement of the object.
Attention to the direction of movement of electrons: In general, electrically charged particles migrate from the negative pole of an electrical source to the positive pole. In the right-hand rule, however, a current direction of + to - is assumed. That is, the movement is exactly the opposite here.
The Lorentz force
The Dutch physicist Henrik Lorentz has studied in detail the modes of action described by the three-finger or hand rule. To honor him was the force acting on the moving charge carrier within this setup, also called Lorentz force.
The Lorentz force is the force that moves a current-carrying conductor within a field of a magnet. Depending on the flow direction of the current in the conductor, the Lorentz force acts in different directions.
Left Hand Rule or Right Hand Rule: Differences
Unlike the right-hand rule, the left hand rule is always used when the flow of electrodes (current flow) goes from + to -. In concrete terms, this means that the left hand rule is always used when talking about electric current with negative charge carriers. The right-hand rule thus starts from positively charged particles, so-called cations.