Introduction

Let us look at the vast stary night sky. Let us think of the galaxy full of scintillating fire balls. Let us experience a ride on a high speed Maglev train in Miyazaki, Japan. We must find one thing common in these. Everything is so very balanced yet so moving. The equilibrium state or the multiple equilibrium states are adjoined by the consequent transient states of these events. They are characterized by different force fields. We can imagine our physical existence is situated and controlled by four major force fields. They are:

• a. Gravitational force field

• b. Electrical force field

• c. Magnetic force field

• d. Atomic or Nuclear force field

Out of these four the first three are governed by inverse square law. Bodies which are inversely proportional to the distance between them and directly proportional to their dimension (i.e. mass, charge, magnetic pole intensity). The gravitational force field is both attractive and repulsive. Electrical and magnetic field generally coexist. We can call them sister fields. In most of the cases we derive one as a result of another one. Thus we can easily establish a linear relationship between them. We as an electrical engineer mostly deal with these two sister fields and their combined network. Power system is an electro-magnetic system. Thus, we should have a profound study on electric and magnetic field with prior importance. This chapter will enlighten us how these two fields work and react to each other.