Force between Two Parallel Current-Carrying Conductors-Definition of Ampere
In the current-carrying conductor, there is always the existence of a magnetic field. This magnetic field exerts the force on the current-carrying conductor. It can be said that when the two conductors are placed near to each other then both of them will exert a magnetic force on each other.
Let consider a system that is shown in the above figure. Two parallel conductors are containing current, and they are separated by the distance d such as one of them is carrying current as I1 and other is containing current as I2. The same magnetic field is experienced by the second conductor, at every point along the length due to the action of the first conductor. The direction of the magnitude of the force is also indicated in the figure, and this magnitude is found by using the right-hand thumb rule. Due to the first conductor, the direction of the magnetic field is downward.
Determination of Magnitude
With the help of Ampere’s circuital law, the magnitude of direction due to the first conductor can find out. The force on the segments of the length of the second conductor can also be calculated. Similarly, the force that is exerted on the first conductor due to the second conductor can also be calculated. Due to the flow of current in the same direction, the attraction can be observed between the conductors. When the current is flowing in the opposite direction, then the conductors are repelling each other. This acting force is responsible for the pinch effects in the plasmas, and electric arcs. Either, there is current in the wire or not, the force always exists.
In the electric arcs when the current is moving in the parallel direction, then there is an attraction that causes the squeezing of current into smaller tubes. In the larger circuit breakers, which are used in the neighborhood of the power distribution system, the pinching effect can concentrate on the arc between the plates of switch that is trying to break the burn holes, large current, and even causes the ignition of equipment. Another kind of the pinch effect can be found in the solar plasma, where the jets of ionized materials (solar flares), are shaped due to magnetic forces.
Definition of Ampere
The operational definition of ampere is based on a force that is present between the current-carrying wires. According to official definition of ampere, 1 ampere is current that flows through each of parallel conductors having the infinite length, and are separated by the distance of one meter in the space, that is free of other kinds of magnetic fields and it exerts the exact force of 2 × 10−7 N/m on each of the conductor.