Magnetic Field | What is Magnetic field | Properties of Magnetic lines of forces

Magnetic Field

Just as an electric field exists near a charged object, a similar magnetic field exists around a

magnet. If an isolated magnetic pole is brought near a magnet, it experiences a force according to Coulomb’s laws. The region near the magnet where forces act on magnetic poles is called a magnetic field. The magnetic field is strongest near the pole and goes on decreasing in strength as we move away from the magnet.

The space (or field) in which a magnetic pole experiences a force is called a magnetic field.

The magnetic field around a magnet is represented by imaginary lines called magnetically

lines of force. By convention, the direction of these lines of force at any point is the direction along which an *isolated unit N-pole (i.e. N-pole of 1 Wb) placed at that point would move or tends to move.

Following this convention, it is clear that magnetic lines of force would emerge from the N-pole of the magnet, pass through the surrounding medium and re-enter the S-pole. Inside the magnet, each line of force passes from S-pole to N-pole (See Fig. ) thus forming a closed-loop or magnetic circuit. Although magnetic lines of force have no real existence and are purely imaginary, they are a useful concept to describe the various magnetic effects.

Properties of magnetic lines of force.

The important properties of magnetic lines of force are :

(i) Each magnetic line of force forms a closed-loop i.e. outside the magnet, the direction of a

magnetic line of force is from north pole to south pole and it continues through the body

of the magnet to form a closed loop (See Fig.)

(ii) No two magnetic lines of force intersect each other. If two magnetic lines of force intersect,

there would be two directions of the magnetic field at that point which is not possible.

(iii) Where the magnetic lines of force are close together, the magnetic field is strong and

where they are well spaced out, the field is weak.

(iv) Magnetic lines of force contract longitudinally and widen laterally.

(v) Magnetic lines of force are always ready to pass through magnetic materials like iron in

preference to pass through non-magnetic materials like air.

It may be noted that in practice, magnetic fields are produced by (a) a current-carrying conductor or coil or (b) a permanent magnet. Both these means of producing magnetic fields are widely used in electrical engineering

Comments

Faraday's Law of electromagnetic induction | Lenz's law | Law of electromagnetic induction

Faradays Law of Electromagnetic Induction : Faraday's laws state that an emf is induced in a circuit which is (i) Directly proportional to the time rate of change of flux enclosed by the circuit. (ii) Directly proportional to N the no. of turns of the circuit. Combining, the two laws, Faraday's laws of induction can be expressed mathematically as Here negative sign is due to Emil Lenz, who after Faraday's experiments suggested that the direction of the induced current is always such as to oppose the action that produced it. As we know Faraday's law as given by equation (ii.1) is one of the two basic relationships upon which the whole theory of electromagnetic and electromechanical energy conversion devices are based and today we have the generator and motor (electric) operating based on this theory. Also, Faraday was the first to identify emf of self-induction, i.e., here we have only one coil and it is connected to a de source through a switch. When current is flowin...

Emf Induced in a Rotating Coil placed in a Magnetic Field | Emf Induced | Magnetic Circuit

EMF Induced in a Rotating Coil Placed in a Magnetic Field : 👉 Consider a coil AB placed on the outer periphery of a soft iron solid cylindrical rotor. The stator poles carry the exciting coils. When current flows through exciting coils flux is set up as shown in Fig. 1. The rotor is rotating in the clockwise direction at a constant angular velocity of Z radians/sec. The direction of the linear velocity (perpendicular to the plane of the coil) acting on conductor A is shown in Fig. 1 which makes an angle T with the direction of the field. The component of velocity perpendicular to the field is v p = v sin T . FIG: 1 The emf induced in conductor A , e = Blv sin T Where, B = f...

Types of Network Element | Active and Passive Network | linear and Non-linear Network | Circuit elements

In this article, we will discuss what are the basic network elements and types of network elements. Types of network elements We can classify the Network elements into various types based on some parameters. Following are the types of network elements − Active Elements and Passive Elements Linear Elements and Non-linear Elements Bilateral Elements and Unilateral Elements Lumped Elements and Distributed Elements Active Elements and Passive Elements Active or passive based on the ability to deliver power. Active Elements deliver power to other elements, which are present in an electric circuit. Sometimes, they may absorb the power like passive elements. That means active elements have the capability of both delivering and absorbing power. Examples: Voltage sources and current sources. Passive Elements can’t deliver power (energy) to other elements, however, they can absorb power. That means these elements eith...

ElectricalTopics.in

Search This Blog