Ampere is the international unit of electric current. Ampere is the international unit of electric current. It is abbreviated as ampere and its symbol is A. It is defined as: Two infinitely long parallel straight wires 1 meter apart in a vacuum carry an equal constant current. When each wire

When the force on each wire is 2×10-7N, the current on each wire is 1 ampere.

Currents smaller than amperes can be expressed in units such as milliamperes and microamps.

1 A = 1000 mA 1 mA = 1000 microA The common unit on the battery is mAH (milliamp hour). For example, 500mAH means that the battery can provide 500mA × 1hr = 1800 coulombs of electrons, which means it can provide one consumption

An appliance with a capacity of 500mA uses one hour's worth of electricity.

Ampere's rule Ampere's rule expresses the relationship between current and the direction of the magnetic field lines of the magnetic field excited by the current. It is also called the right-hand spiral rule.

(1) Ampere's rule for linear current Hold the wire with your right hand so that the direction pointed by the straight thumb is consistent with the direction of the current. Then the direction pointed by the four bent fingers is the direction of the magnetic field lines.

(2) Ampere's rule for ring current If the four bent fingers of the right hand are in the same direction as the ring current, then the direction pointed by the straight thumb is the direction of the magnetic field lines on the central axis of the ring current.

Ampere's law for linear current also applies to a small segment of linear current.

The ring current can be regarded as composed of many small straight-line currents. For each small straight-line current, the direction of the magnetic induction intensity on the central axis of the ring current can be determined using Ampere's rule of linear current.

Superimposed together, the direction of the magnetic field lines on the central axis of the ring current is obtained.

Ampere's rule for linear current is basic. Ampere's rule for circular current can be derived from Ampere's rule for linear current. Ampere's rule for linear current is also applicable to the magnetic field generated by the linear motion of the charge. At this time, the direction of the current is consistent with the motion of the positive charge.

The direction is the same as that of negative charge movement.

Amperometric titration is an electrometric titration analysis method that uses changes in current in an electrolytic cell to indicate the end point of a titration.

It is divided into amperometric titration with one polarized electrode and amperometric titration with two polarized electrodes.

Amperometric titration of one polarizing electrode using a dropping mercury electrode as the polarizing electrode is called polarographic titration.

Amperometric titration with two polarized electrodes is called dead stop end point method or double amperometric titration.

Ampere's force The force of a magnetic field on an electric current.

The force exerted by the current element Idl in the external magnetic field B is df=Idl×B. The direction of Ampere's force is determined by dl and B according to the right-hand screw rule. The magnitude of Ampere's force is df=BIdlsina, where a is between dl and B.

angle.

The force exerted by a magnetic field on any current-carrying wire is the vector sum of the forces on each current element.

Ampere's force formula is part of Ampere's law concerning the interaction between current elements.

Ampere's force is the macroscopic manifestation of the Lorentz force exerted by a magnetic field on moving charges.

1. The effect of magnetic field on current. Bar magnets can pick up iron blocks of smaller mass within a certain distance, but huge electromagnets can pick up tons of steel blocks. This shows that the magnetic field is strong or weak. How to express the magnetic field?

What about its strength?

We use the force exerted by the magnetic field on the current - Ampere's force to study the strength of the magnetic field.

2. What are the factors that determine the size of ampere force?

(1) It is related to the size of the current. The size of the force exerted by the magnetic field on a straight energized wire perpendicular to the direction of the magnetic field is related to the size of the current in the wire. If the current is large, the force will be large; if the current is small, the force will be small.

(2) It is related to the length of the current-carrying wire in the magnetic field. The size of the force exerted by the magnetic field on a straight current-carrying wire perpendicular to the direction of the magnetic field is related to the length of the current-carrying wire in the magnetic field. A long wire has a large force; a short wire has a large force.

Little force.

(3) It is related to the direction in which the wire is placed in the magnetic field. Keep the size of the current and the length of the energized wire constant, and change the angle between the wire and the direction of the magnetic field. When the angle is 0°, the wire does not move, that is, the direction of the current and the magnetic field.

When they are parallel, they are not affected by the Ampere force; when the angle increases to 90°, the swing angle of the wires continues to increase, that is, when the current is perpendicular to the direction of the magnetic field, the Ampere force is the largest; when it is neither parallel nor perpendicular, the Ampere force

The size is between 0° and the maximum value.

3. Magnetic induction intensity. Use L to represent the length of the energized wire, I to represent the current, and keep the direction of the current and magnetic field perpendicular. The magnitude of the ampere force FIL on the energized wire is represented by B. This ratio is B=F/IL.

The physical meaning of B is: if the current-carrying wire is placed vertically at the same position in the magnetic field, the B value remains unchanged; if the position of the current-carrying wire is changed, the B value changes accordingly.

It shows that the size of the B value is determined by the position of the magnetic field itself.

For wires with the same current and length, the Ampere force F placed at a location with a large B value is also large, indicating a strong magnetic field.