1. The electromagnet shown in the Fig. 1 below is to be used to lift an iron slab of mass M=150 kg. The surface roughness of the iron is such that when the iron and the electromagnet are in contact, there is a minimum air gap of 0.2 mm in each leg. The electromagnet has infinite permeability and the cross- sectional area Ac is 25 cm². The number of turns of N-turn winding is 350 and the winding coil resistance is 32. Calculate the minimum coil voltage which must be used to lift the iron slab against the force of gravity. Neglect the reluctance of the iron. Hint: Gravitational acceleration constant is 9.8 m/s². N-turn 88 8 winding Electromagnet, cross-sectional area Ac 8 Iron slab, mass M Fig.1 Electromagnet lifting an iron slab