Pages: 11

In our universe, there are many particles which are the sources of the electromagnetic radiation. Many of them have definite amount of charge which creates the electromagnetic field. In the atom, the negatively charged electrons move around the positively charged nucleus, Although, nucleus consists of neutrons and protons where the neutrons do not have any charge, while the protons have positive charge. In this way, we can say that the charge is a fundamental property of the particle and it is bound to the matter. If a rod of amber is rubbed with fur, it acquires the property of attracting the small pieces of the papers. In this way, we can say that the some electrons are rubbed off the fur that is why, it acquires the property of the attraction. Further more, if a glass rod is rubbed with silk cloth, the glass rod becomes positively charged.

Pages: 24

The gravitational force is a common force that acts between two distant masses. Similarly, the coulomb force acts between two stationary charges. The limitation of the coulomb force is that it acts between two point charge. If there is a distribution a charges, then the concept of the electric field is a powerful tool to handle such a system. A stationary charge acts an electrostatic force on the other charges in the region of space. It mean that a single charge creates an electric field in the space near by it. In this chapter, we shall discuss the electric field and its applications.

Pages: 32

In the previous chapters, we have discussed the force between two charges and the applications of the electric field. We have investigated the electric field due to a charge or an assembly of the charges using the concept of positive test charge q 0 . In this chapter we shall solve the electrostatic problems using Gauss’s law.

Pages: 31

We are familiar with the electrostatic force that may be presented in terms of the electric field. Since electric field is a vector field, the electrostatic force is conservative force. In the experimental physics, the concept of the electric field may be transformed into the electric potential. The concept of electric potential or potential difference plays an important role in electrical engineering.

Pages: 33

We have already solved the various potential or field problems with known charge distribution. If the potential is known, charge q, electrostatic force, electric field etc may be computed easily. In solving such problems, an integration method is employed, that is, in other words, we take an integration over a definite charge distribution. We known that the electric field is given by 5.1 https://www.w3.org/1998/Math/MathML" display="block"> E = − ∇ V https://www.w3.org/1999/xlink" content-type="black-white" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003529125/2f63d8d5-a843-49ec-8c5d-24560dc67690/content/math5_1_B.tif"/> that is, E can be taken as a negative gradient of the potential, this is because, the electric field is a conservative field. In this way, we can assume that the potential function V is associated with a given region of space. If the region of the space is not bounded, it has some difficulty in obtaining the solution to the potential problems. That is, there is a no unique solution to the problem. The uniqueness theorem helps in obtaining the solution to the electrostatic problems. This solution can be obtained using certain boundary conditions. In this way, a complex problem may be solved to a high degree of accuracy. Thus, Laplace and Poisson’s equations provide a good solution of the potential problems with known boundary conditions.

Pages: 56

We know that a work is needed to form a group of charges and this system consists of an electrostatic energy. In the early days, Volta used the concept of the electrical capacity in analogy with the heat capacity. The electric potential energy is the result of force between the charges. We can produce a useful device by placing two conductors at a distance that can store an electric energy. Thus, a device that can store the electric energy is called the capacitor. In this chapter we shall study about the capacitor and dielectrics.

Pages: 41

In the previous chapters, we have discussed the electric phenomena associated with the charge at rest. In the present chapter, we shall describe the situations having charge in motion. The electric current may exist where the charge is free to move. In different media, the current is caused by the different charge. In conductors the current is due to the motion of the free electrons. However, in semiconductors, the current is caused by the motion of the electrons and holes. The motion of positive and negative ions constitute a current in the electrolytes. Moreover, the displacement current is the result of the bound charge in the dielectrics. It is the important fact that when current flows through the resistance, there will be dissipation of the energy. In this chapter, we also analyze the electric circuits with the fundamental electrical theory and we shall discuss the relations among the electrical parameters viz, current, voltage, resistance and electric field etc.

Pages: 42

The natural magnets, originally called Iodestones were discovered many centuries ago. It was found that magnetic behavior of materials came into picture with the ancient city of Magnesia in Asia Minor. In 1820, Danish physicist Hans Christan Oersted showed that the electric current gives rise magnetic force. A current carrying conductor is associated with the magnetic field and causing a deflection in the compass needle. When a magnetized needle is suspend freely, it always in the north and the south directions. In this chapter we shall study the magnetic field and magnetic interactions.

Pages: 28

In the previous chapters, we mostly have emphasis on source of direct current (dc). This current remains constant with time as shown in Fig. 9.1. Direct current contains zero frequency.

Pages: 21

A static charge produces an electric field and a moving charge produces static magnetic field. In the previous chapter, we have seen how the electricity produces magnetism. If we think about the converse of this and a possibility arises that the magnetic effect produces electric current. After Hans-Christian Oersted, Michael Faraday started the experiments and showed that the magnetic field may produce the electric current. In 1931, Faraday observed that if a magnet is moved in the vicinity of a coil, a current is induced in the coil and is indicated by a galvenometer, as shown in fig. 10.1. He concluded that the induced current was dependent not only on the magnetic flux itself, but on its time rate of change also. The changing magnetic field produces an induced emf. Faraday gave a relation between time rate of change of magnetic flux and the induced emf. This relation is called the Faraday’s law of electromagentic induction.

Pages: 29

James Clerk Maxwell (1832–1879) gave the relation between charges, current and electromagnetic field in the form of four mathematical equations. These equations are a type of unified theory, which describe all the phenomena of classical electromagnetism. This theory proves that the light waves are the electromagnetic waves and the speed of the electromagnetic waves is given by https://www.w3.org/1998/Math/MathML" display="block"> c = 1 μ 0 ∈ 0 ∈ 0 = 8.85 × 10 − 2 C 2 / Nm 2 μ 0 = 1.26 × 10 − 6 = 4 π × 10 − 7 Wb / A − m https://www.w3.org/1999/xlink" content-type="black-white" xlink:href="https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003529125/2f63d8d5-a843-49ec-8c5d-24560dc67690/content/math11_325_1_B.tif"/>