A regular magnet have two ends usually marked as “north” and “south” and it attracts iron and steel. The fundamental rule of regular magnet is that opposite attracts and likes repel. An electro-magnet too has the same characteristics, and the only difference is that it is temporary. A coil of current carrying wire becomes an elecro-magnet with the magnetic field strongest at the two ends of the coil, the north and south poles. The electro-magnet remains magnetic only as long as the electricity flows through it (Barron’s series, 2003, p.172). The electro magnetic lines operate on the latent magnetic particles of iron in the same manner as they are operated on by the magnetic lines of a permanent steel magnet, arranging those particles in regular consecutive polar order according to the laws of magnetics (p.271).
Magnetism and electricity is closely related. Magnetism is used to generate electricity and electricity produces a magnetic field. The areas around a magnet where the force is felt is called magnetic field. Electricity flowing through a wire sets up a magnetic field around the wire. A magnetic field can also produce electricity. If a wire is passed through a magnetic field, electricity would be generated in the wire. Electric generators are based on this principle (Barron’s series, 2003, p.172).
Electro magnetic induction is all pervading in our daily life and it is used in most gadgets of daily use like microwave, refrigerator, cell phone, music system, power transformer, car brake batteries, house alarm, and fire alarm. More heartening is the fact that recently, an agricultural research scientist has used EI to measure changes in the electrical conductivity of soil. This breakthrough research will help trace nutrients present in the soil.1
Editorial department, Inc. Barron’s educational series (2003) How to prepare for the ASVAB: Armed Services Vocational Aptitude Battery, Barron’s Educational Series, p.592
Sturgeon, W (1837) The Annals of Electricity, Magnetism, and Chemistry and Guardian of Experimental Science, Sherwood, Gilbert, and Piper, p.507
1. Using electro-magnetic induction to trace soil nitrogen, Science Daily, Oct 11, 2004, retrieved from the url: http://www.sciencedaily.com/releases/2004/10/041011075626.htm on 17th June, 08