20.Which material are mostly used for making electro magnet?a) Silicon steelc) Alnico alloy steelb) Tungsten steeld) Cast iron

20.Which material are mostly used for making electro magnet?a) Silicon

1.	20.Which material are mostly used for making electro magnet?a) Silicon steelc) Alnico alloy steelb) Tungsten steeld) Cast iron
Answer» <p>For an electromagnet, you need a core material with low remnance. That is, when you remove the magnetomotive force (current in the coil) the core will (mostly) demagnetise and let the load or armature go. Iron or silicon steel has this property.</p><p>Other steel alloys do not necessarily have this property. They have a high remnance which means they remain highly magnetised even wjen the mmf is removed. This is an undesirable property for an electromagnet.</p>