1　仪器装置图 (如图 1所示 )图 12　仪器特点及用途光源在没有通电时 ,观察者看到的磁场情况如图2所示 ,(这时不能观察到磁场中的磁力线 )通电以后 ,光源照射到平行铁丝上的光 ,通过玻璃的反射作用 ,形成的虚象恰巧处在磁极Ｎ与Ｓ之间 ,这时候教具前方的观察者“看”到的磁力 1 instrument device diagram (as shown in Figure 1) Figure 12 instrument features and uses the light source in the absence of electricity, the magnetic field as viewed by the observer as shown in Figure 2, (at this time can not observe the magnetic field lines) after power, The light irradiated by the light source on the parallel wire is reflected by the glass, and the virtual image formed happens to be between the magnetic poles N and S. At this time, the observer in front of the teaching aid “sees” the magnetic force.