Ampere&# 39; s force is energizedwirewaystaymagnetic fieldReceived inForce。By French physicist A·ampereFirst, it is determined by experiment.It can be expressed as:Current intensitybyIThe length of isLStraight wire, placed inMagnetic inductionbyBIn the uniform external magnetic field off=IBLsinα, whereαIs the current direction in the wire andBBetween directionsincluded angle，f、L、IandBThe units of are N, m, A and T.The direction of ampere force is perpendicular to the direction ofmagnetic fieldThe plane determined by the direction, andI、BAndFThe directions of the three are determined byLeft-handed ruleJudgment.arbitrarilyshapewirewayThe ampere force in a uniform magnetic field can be regarded as infinitestraight lineCurrent elementIΔLAmpere force in magnetic fieldvectorand[1]。
magnetic fieldGalvanicForceUsually calledAmpere force,In memory of French physicistsampereStudy the outstanding contribution of magnetic field to the force of current.
The force applied to an energized wire in a magnetic field.Current isI, length isLStraight conductor of.stayUniform magnetic fieldBThe magnitude of the ampere force in is:
F=ILBsinα, whereαFor（I,B）, is the angle between the current direction and the magnetic field direction.
The direction of the ampere force is determined byLeft-handed ruleJudgment.The current of any shape can be divided into many segments under the force of non-uniform magnetic fieldCurrent elementIΔLThe magnetic field B at each current element can be regarded as a uniform magnetic field, and the ampere force applied is ΔF=IΔL·BsinαThe sum of these many ampere force vectors is the force on the whole current.
It should be noted that when the current direction and the magnetic field directionidenticalorcontraryWhen, that isα=When 0 or π, the current is not affectedMagnetic forceeffect.When the current direction is perpendicular to the magnetic field direction, the maximum ampere force on the current isF=BIL。BIs the magnetic induction intensity,IIs the current intensity,LIs the length of the conductor perpendicular to the magnetic induction line.
Left-handed rule
The essence of ampere force is the resultant force of Lorentz force on the charge that forms the directional movement of current.The magnetic field has a strong effect on the moving charge, which is the conclusion obtained from the experiment.Similarly, when the movement direction of the charge is parallel to the magnetic field, it is not affected by Lorentz force, which is also known from experimental observation.When the current direction is parallel to the magnetic field, the directional movement direction of the charge is also parallel to the magnetic field direction, the Lorentz force is zero, and the resultant ampere force is zero.
Lorentz forcedo not doWorkBecausepowerThe direction of is perpendicular to the motion direction of the particle, according to the formula of workW=FScosθ，θ=At 90 °,W=0。The ampere force is perpendicular to the current direction in the wire, but not necessarily to the moving direction of the wire. Generally, it is in the same straight line, so the ampere forceWorkNot zero.
Force direction
The direction of force on a wire in a magnetic field.according toLeft-handed rule: Extend the left hand, make the thumb perpendicular to the other four fingers and in a plane, let the magnetic feeling line penetrate from the palm of the hand, and the four fingers pointelectric currentDirection: the thumb points to the direction of ampere force (i.econductorForce direction) (see the upper right figure).
significance
Announce
edit
summary
Amberi
The experiment shows that a section of electrified straight wire MN is placed atmagnetic fieldWhen the wire direction is perpendicular to the magnetic field direction, the ampere force on the current is the largest;When the wire direction is consistent with the magnetic field direction, the current is not subject to the ampere force;When the direction of the wire is oblique to the direction of the magnetic field, the ampere force on the current is between the maximum value and zero.
A large number of experiments have shown that the magnitude of the ampere force F and the current intensity applied to a section of electrified wire perpendicular to the magnetic field somewhere in the magnetic fieldIAnd conductor lengthLIs proportional to the product ofF=BIL
When the angle between current and magnetic field direction isαWhen, use:F=BILsinα
The value of force
The significance of ampere force lies in that, on the one hand, it further points out thatelectricAndmagnetismThe interrelation of;The other is application value,MotorIts working principle is based on ampere force.
The essence of the work done by ampere force is to transfer the energy of the power supply to the electrified straight wire, andmagnetic fieldIt cannot provide energy by itself. The characteristics of ampere force doing work areStatic frictiondoWorkbe similar.
