Magnetic Effects of Electric Current

Magnetic Effects of Electric Current – Class 10 Science Chapter 13 Notes

Magnetic Effects of Electric Current is one of the most important chapters in your class 10th science syllabus. To get with flying colours in your exam you must have a very good command of this particular chapter. Here, we have provided detailed on magnetic Effects of Electric Current – Class 10 Science Chapter 13 notes.

Overview

Hans Christian Oersted in 1820, discovered that a compass needle gets deflected when a current-carrying metallic conductor has placed nearby it. According to him, the deflection compass needle was due to the magnetic field produced by the electric current. Thus, it was concluded that electricity and magnetism are related to each other.

Magnetic Field

The space/area around a magnet in which its magnetic effect can be experienced, i.e. its force/presence can be detected, is called a magnetic field.
The magnetic field is a vector quantity. The SI unit of the magnetic field is tesla and the smaller unit of the magnetic field is called ‘gauss’.

Magnetic Field - Class 10 Science Chapter 13 Notes

Magnetic Field Lines

The imaginary lines which represent the magnetic field around a magnet are known as magnetic field lines. When iron filings are kept near a magnet, they get arranged in a pattern that represents the magnetic field lines.

Properties Of Magnetic Field Lines:

Magnetic Field Lines have the following properties:

  1. They originate from the North Pole of a magnet and finish at its South Pole, by convention.
  2. These lines are closed and continuous curves.
  3. They are crowded near the pole, where the magnetic field is strong and separated far from the poles, where the magnetic field is weak.
  4. Field lines never intersect with each other. If this happens, that would mean that there are two directions of the magnetic field at the point of intersection, which is impossible.

Magnetic Field At a Place Due a To Current-Carrying Conductor:

Whenever any kind of electric current flows through a conductor, a magnetic field is produced around it. The pattern of the magnetic field produced by a current-carrying conductor depends on its shape. Different magnetic field patterns are induced by current-carrying conductors of different shapes.

Magnetic Field At a Place Due a to Current through a Straight Conductor:

The magnetic field lines around a current-carrying straight conductor are formed in the shape of concentric circles whose centres lie on the wire. The magnitude (amount) of magnetic field ‘B’ produced by a straight current-carrying wire at a given point is:

Magnetic Effects of Electric Current
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  1. Directly proportional to the electric current ‘I’ which is passing through the wire.
    i.e. * B ∝ I
    If the magnitude of the current is increased, then the magnetic field produced is will also increase and hence, vice-versa.
  2. And the magnetic field is also, inversely proportional to the distance ‘r’ from the wire
    i.e. * B ∝ I/r
    The attractive (magnetic) field is more grounded (strong) at a point that is closer to the conductor and continues diminishing on creating some distance from the conductor.
    If the direction of current in a straight wire is no then the direction of the magnetic field produced by obtained by Maxwell’s right-hand thumb rule.

Maxwell’s right-hand thumb rule:

It states that if you hold the current-carrying straight wire in the grip of your right hand in such a way that the stretched thumb points in the flow of direction of the current, then the direction of the magnetic field is given by the direction of curl of the fingers.
This rule is additionally also called Maxwell’s corkscrew rule.

Magnetic Effects of Electric Current
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Magnetic Field At a Place Due to a Current through a Circular Loop:

The magnetic field lines due to a circular coil are at every point on a current-carrying circular loop, the magnetic field is in the form of concentric circles around it, the circles would become larger and larger.
Whenever we arrive at the center point of the circle, the field gives off an impression of being a straight line.
The magnetic field produced by current-carrying circular wire (loop) at a given point is:

Magnetic Field
  1. Firstly is, directly proportional to the amount of current (I) flowing through It.
    i.e. * B ∝ I
  2. And secondly, it is, directly proportional to the number of turns (N) of the wire.
    i.e. * B ∝ N
    This is because the electric current flowing in each turn is in the same/similar direction. Thus, the strength (amount/magnitude) of the magnetic field produced by a current-carrying circular coil can be increased by:
    (a) increasing the number of turns (rotations) of the coil/conductor.
    (b) increasing the current flowing through the coil/conductor.

Some important topics for class 10th board exams:-

  1. CARBON AND ITS COMPOUNDS CLASS 10th Notes
  2. Define Resistivity Class 10th

Electromagnetic Induction

An electric current produced in a limited circuit by a changing magnetic field is called an induced current. This phenomenon is called electromagnetic induction. This was discovered by Michael Faraday.

Magnetic Effects of Electric Current

Fleming’s Right-Hand Rule

Moving a bar magnet towards a coil induces an electric current in the coil circuit, as indicated by deflection in the galvanometer needle. Then, in this case, the direction of the induced current is given by Fleming’s right-hand rule. It states that, if the forefinger, middle finger, and thumb of the right hand are elaborated at right angles to each other, with the forefinger in the direction of the magnetic field and the thumb in the direction of the movement of the wire, also the induced current in the wire is in the direction of the middle finger.

Fleming's Right-Hand Rule - Class 10 Science Chapter 13 Notes

Galvanometer

It is an instrument that is used to detect the presence/availability of electric current in a circuit. The pointer remains at zero (the center of the scale) for zero current flowing through it. Depending upon the direction of the current, it deflects either to the left or to the right of the zero mark.

Magnetic Field At a Place due to Current in a Solenoid:

A solenoid is a kind of coil consisting of a large number of circular turns (rotations) of insulated copper wire. These turns are wrapped closely to form a cylindrical shape.

The field lines around a current-carrying solenoid are exactly the same as that produced by a bar magnet. This infers that a current-conveying solenoid goes about as it has a North pole and a South pole. The field lines inside the solenoid are corresponding to one another. In this way, the strength of the attractive field is something similar at all the points inside the solenoid.

Electric Motor:

Electric Motor is a rotating device (machine) used for converting electric energy into mechanical energy.

• Principle

It depends on the rule that when a rectangular loop is put in an attractive field and current is gone through it, two equivalent and inverse powers follow up on the curl which pivots it constantly.
The speed (number of rotations) of rotation of the motor can be increased by:

  1. Increasing the strength/magnitude of the electric current in the coil.
  2. Increasing the quantity of turns of wire in the coil.
  3. Increasing the area of the coil.
  4. Increasing the strength/magnitude of the magnetic field.
Electric Motor:

Commercial Electric Motor:

A commercial electric motor has the following factors (Components):

  1. An electromagnet in the place of a regular permanent magnet.
  2. A large number of turns/rotations of conducting wire in the current-carrying coil.
  3. A soft iron core on which the coil is wound (wrapped). The combination/mixture of soft iron core and coil is called the armature. It upgrades the force of the motor.
    An electric motor is used in electric fans, refrigerators, mixers, washing machines, computers, MP3 players, etc.

Electric Generator

It is a gadget that is by and large used to change mechanical energy over to electrical energy. An electric generator is put together or works concerning the principle of electromagnetic induction.

• Parts Of Electric Generator:

The various parts of an electric generator are clarified beneath:

  1. Armature: It is a coil having an enormous number of turns of insulated copper wire wound over a soft iron core.
  2. Field magnet: It is a strong magnet that gives a uniform attractive field. It is put opposite to the hub of revolution or curl between the North and South poles.
  3. Slip rings: In an AC generator, a slip rings sort of commutator is utilized. Slip rings are full rings with which the closures of the loop are in touch. Though DC generator utilizes split ring type commutator which are half rings with which the finishes of the armature loop are in touch.
  4. Brushes: Two fixed metallic carbon brushes are in touch with outer gadgets and rings.
Magnetic Effects of Electric Current
Source: examfear

Kinds of Electric Generator Electric Generators:

Electric generators are of two kinds:

  1. Alternating Current generator (AC generator)
  2. Direct Current generator (DC generator)
  • AC generator – An electric flow whose extent shifts with time and course switches occasionally is called substituting flow. It is indicated by AC. Wellsprings of AC are nuclear energy generators, atomic power generators, and so on.
  • DC generator – An electric current whose magnitude is either constant or variable but the direction remains the same is called direct current. It is denoted by DC. Sources of DC are a dry cell, battery, DC generator, etc.

Domestic Electric Circuits

Electricity generated at power stations is brought to our home by two thick copper or aluminium wires. One of these is called live wire (in red insulation cover), which is at a potential 220 V with a frequency of 50 Hz and the other is called neutral wire (in black insulation cover), which is at zero potential.

These wires (live and neutral) pass into an electricity meter (connected in homes) through the main fuse. They are connected to the line wires in the home through the main switch. Usual there are two separate circuits in a house, the lighting circuit with a 5 A fuse (bulbs, fans, etc.) and the power circuit with a 15 A fuse (geysers, air coolers, etc.).

Magnetic Effects of Electric Current

Faults and Safety Measures in Domestic Electric Circuit:

  • Earth Wire –To avoid the risk of electrical shock, the metal body of appliances is earthed. The metal case of the appliance is connected to the earth (i.e. zero potential) by means of a metal wire called earth wire (in green insulation cover). One end of the metal wire is buried in the earth. The appliances are connected to the earth by using the top pin of a 3-pin plug. Earthing saves us from electrical shocks.
  • Fuse – It is a safety device. It is a thin wire made of tin and lead alloy having a low melting point of around 200 °C. It is used to prevent the possible damage caused by overloading and short-circuiting.
  • Short-Circuiting – If the live wire and neutral wire come in contact either directly or via conducting wire, then it is called short-circuiting. In this case, the resistance of the circuit is almost zero which results in the flow of a large current. This heats the wire dangerously and may lead to a fire.
  • Overloading – If many electrical appliances of high power rating are switched on at the same time, then they draw a large current from the circuit. This is called overloading. The large amount of current flowing through the wire excessively heats up the wire and may lead to fire.

Conclusion: class 10 science chapter 13 notes

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