Bar Magnet磁体
The lines of magnetic field from a bar magnet form closed lines. By convention, the field direction is taken to be outward from the North pole and in to the South pole of the magnet. Permanent magnets can be made from ferromagnetic materials. 条形磁体产生的磁场线形成闭合的线。根据惯例，磁场方向被定义为从磁体的北极指向南极。永磁体可以由铁磁性材料制成。 As can be visualized with the magnetic field lines, the magnetic field is strongest inside the magnetic material. The strongest external magnetic fields are near the poles. A magnetic north pole will attract the south pole of another magnet, and repel a north pole. 正如磁感应线所显示的，磁场在磁性材料内部最强。最强的外部磁场靠近磁极。磁北极会吸引另一个磁铁的南极，排斥另一个磁铁的北极。 |
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The magnetic field lines of a bar magnet can be traced out with the use of a compass. The needle of a compass is itself a permanent magnet and the north indicator of the compass is a magnetic north pole. The north pole of a magnet will tend to line up with the magnetic field, so a suspended compas needle will rotate until it lines up with the magnetic field. Unlike magnetic poles attract, so the north indicator of the compass will point toward the south pole of a magnet. In response to the Earth's magnetic field, the compass will point toward the geographic North Pole of the Earth because it is in fact a magnetic south pole. The magnetic field lines of the Earth enter the Earth near the geographic North Pole. 条形磁铁的磁场线可以用罗盘来追踪。罗盘的指针本身就是一个永磁体，罗盘的北端指示器是一个磁北极。磁铁的北极会倾向于与磁场方向对齐，因此悬吊的罗盘指针会旋转直到与磁场方向对齐。不同磁极相互吸引，因此罗盘的北端指示器会指向磁铁的南极。响应于地球的磁场，罗盘会指向地球的地理北极，因为实际上它是一个磁南极。地球的磁场线在地理北极附近进入地球。 |
| Comparison of magnetic and electric fields
磁感应场与电场的比较 | Compare to solenoid magnetic field
与螺线管磁场比较 |
Magnetic field concepts
| HyperPhysics***** Electricity and Magnetism
HyperPhysics ***** 电学和磁学 | R Nave |
