| 摘要 |
FIELD: physics. SUBSTANCE: training aid-pendulum is designed to expand number of demonstrated experiments and to raise their authenticity including elimination of foreign effect. It is proposed to manufacture pendulum from alloy of two metals (diamagnetic and paramagnetic) which has magnetic permeability equal to one. This means that material of pendulum exerts no effect on braking of pendulum in magnetic field and this braking occurs exclusively due to interaction of magnetic fields of eddy currents and permanent magnetic field of magnet. Second experiment proposed to conduct on this aid is demonstration of screening of pole of magnet by screens made of alloy of diamagnetic and paramagnetic metals. There is no any current in screens in permanent magnetic field. But with movement of pendulum between screens eddy currents are generated in it and secondary eddy currents energy in screens which partially shield permanent magnetic field of magnet. This lead to slower damping of oscillations of pendulum. Third experiment which is proposed to demonstrate with this training aid is oscillations of pendulum fabricated from ferromagnetic material and placed between two plates made from alloy of diamagnetic and paramagnetic metals and its braking as result of action of eddy currents emerging in plates. This experiment shows effect opposite to effect demonstrated in first experiment. Mentioned experiments lead to deeper understanding by scholars of laws and effects of electromagnetic induction. EFFECT: expanded number of demonstrated experiments and raised authenticity of them. |
