Ampere force call force with which magnetic field affects the conductor with current placed in it. Its direction can be defined having used the rule of the left hand and also by the rule of an hour hand.
Instruction
1. If to place the metal conductor with current in magnetic field, then it will be affected by force from this field, Ampere force. Current in metal is the directed movement of a set of electrons, each of which is affected by Lorentz force. Forces operating on free electrons have one size and the identical direction. Developing with each other, they give the resulting Ampere force.
2. Force received the name in honor of the French physicist and the scientist André of Mari of Ampere who in 1820 experimentally investigated action of magnetic field on the conductor with current. Changing a uniform of conductors and also their arrangement in magnetic field, Ampere determined force operating on certain sites of the conductor.
3. The module of Ampere force is proportional to length of the conductor, current in it and to the module of induction of magnetic field. It depends also on orientation of this conductor in magnetic field, in other words, from a corner which forms the direction of current in relation to a vector of induction of magnetic field.
4. If induction in all points of the conductor is identical also magnetic field uniform, then the module of Ampere force is equal to the work of current in the conductor, the module of magnetic induction in which it is of length of this conductor and a sine of the angle between the directions of current and a vector of induction of magnetic field. This formula is right for the conductor of any length if at the same time it completely is in uniform magnetic field.
5. To learn the direction of Ampere force, it is possible to apply the rule of the left hand: if to put the left hand so that four of her fingers specified the direction of current, at the same time lines of the field would be included into a palm, then the direction of Ampere force will show the thumb unbent on 90 °.
6. As the work of the module of a vector of induction of magnetic field on a sine of the angle represents the module components of a vector of induction which is directed perpendicular to the conductor with current, orientation of a palm it is possible to determine by this a component. The perpendicular component to a surface of the conductor has to enter an open palm of the left hand at the same time.
7. For definition of the direction of Ampere force there is other way, it is called the rule of an hour hand. Ampere force is directed in that party from where the shortest turn of current to the field is visible counterclockwise.
8. Action of Ampere force can be shown on the example of parallel currents. Two parallel wires will make a start if currents are sent to them opposite each other and to be attracted if the directions of currents coincide.