There are various concepts involved in electromagnetism which are otherwise difficult to explain to students. Thus an educative tool was constructed for explanation of some concepts like mutual induction, effect of change in core medium, number of turns of coil, etc. All these concepts were explained on one experiment specially designed. This apparatus was used in explaining electromagnetism for one group of undergraduate students between pre and post test. While another group attempt only pre and post test. Using z test the effectiveness of educative tool was tested and it was found to be effective