Summary

Electricity and magnetism, though presented as two separate halves of this chapter for clarity, are in fact two aspects of a single unified phenomenon known as electromagnetism — a fact demonstrated experimentally first by Oersted (current produces magnetism) and then by Faraday (changing magnetism produces current). A firm grasp of the basic definitions (charge, current, potential difference, EMF, resistance), the core laws (Coulomb's law, Ohm's law, the laws of magnetic poles, Faraday's laws, Lenz's law), the standard SI units, and the practical devices built on these principles (motor, generator, transformer, electromagnet, electric bell, fuse) will allow a candidate to confidently handle the great majority of Electricity and Magnetism questions that appear in SSC and RRB examinations, whether they are direct factual recall questions or short numerical-application questions based on the formulas summarised in the reference tables above.