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Chapter 11 – Electromagnetic Induction

The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:

Introduction

Do you know when electromagnetic induction was first discovered? It was first discovered in 1830 by Michael Faraday. He understood the concept of electromagnetic induction by a simple experiment of moving a magnet in and out of the coil. This current was produced, and then he named this phenomenon as Electromagnetic Induction and gave the principle of electromagnetic induction and electromagnetic rotation.

The law states that “a voltage is induced in a circuit whenever relative motion exists between a conductor and a magnetic field and that the magnitude of this voltage is proportional to the rate of change of the flux.”

In simple words, electromagnetic induction generates an electric current in a closed circuit by using magnetic fields.

The law states, “the direction of an induced EMF is such that it will always oppose the change that is causing it.” 

In simple words, the induced current always opposes the motion that started the induced current.

This law also explains the concept of self-induced EMF or back EMF.

Let us see Lenz Law; when you take the magnet’s north pole towards the coil, the coil’s side’s current flow is nearest to the pole and generates opposition to the bar magnet. When you withdraw the magnet from the coil, the current is reversed, and the coil becomes a south pole and attracts the magnet.

Lenz Law follows the conservation of energy. Going by the above explanation, when the magnet is pushed and pulled by the coil because of induced current, a small amount of work is done. Hence, there is a small amount of energy in the form of the heating effect. Thus, it doesn’t violate the conservation of energy.

To understand Motional EMF, we will take the help of a diagram.

Consider a straight conductor AB that moves through a rectangular coil CDEF. The movement is uniform and time-independent.

Let’s consider that the movement of the rod CB is uniform across the loop CDEF and has a constant velocity in m/s.

Therefore, the rectangle CDEP forms a closed circuit due to the uniform motion of AB.

The magnetic flux ΦB enclosed by the rectangular loop CDEF is written as:

ΦB = Blx

EF = x and CD = l

As the conductor is moving and x is changing with time, the rate of flux ΦB induces voltage or EMF by this formula.

ϵ = −dϕBdt=−ddt(Blx)=−Bldxdt=Blv

Motional Electromotive Force can be induced in 2 ways –

  1.   The motion of the conductor in a magnetic field
  2.   Change in magnetic flux in an enclosed circuit.

After deriving the above equation, let us see how Lenz Law follows the conservation of energy. We know,

As the loop CDEF is in a magnetic field, there is current in the coil; a force acts on arm CF,

Hence

If the rod AB is pushed with a constant velocity of magnitude v, then the power will be,

Eddy Currents

The induced voltage within the metallic part of the loop, causing the induced current to flow around it, is called Eddy Currents.

Eddy currents are produced by electromagnetic induction as the current circulates the coil’s core or any connecting metallic elements together in the magnetic field.

The induced current flow works like a negative force, producing resistive heating and power loss within the core. It is applied in a furnace, and it is used to heat and melt ferromagnetic metals.

AC Generator

An AC Generator works on the principle of Fleming’s right-hand rule. When the armature rotates between the magnet’s two poles perpendicularly to the magnetic field, the magnetic flux changes in the armature constantly.

Due to this, an EMF or voltage is induced in the armature. It produces a current that flows through the galvanometer, slip rings, and the brushes. The galvanometer will fluctuate between negative and positive numbers. It is proof that the current is alternating.

Faraday and Henry conducted three types of experiments.

  1. In the first one, Faraday moved a magnet towards a circular coil attached to a galvanometer such that the north pole of the magnet is towards the coil. The result shows that only relative motion generates current in the coil and not when both are kept stationary.
  2. In the 2nd experiment, Faraday moved a current-carrying coil towards the first coil, connected to the battery. It was seen that the magnitude of deflection in the galvanometer of the second coil depends on the speed of the coil when it moves.
  3. In the 3rd experiment, Faraday had two coils put together, which were stationary. He connected one of them to a galvanometer and the other to a battery. When the current was flowing and switched on the key, the galvanometer showed a deflection, but it didn’t show any deflection when the key was switched off.

Electromagnetic Induction is a vital concept of physics and has a host of applications in our day to day life. From induction motors to AC generators, electromagnetic induction applies in a host of operations without which it will not be possible to lead our day to day life.

What do you mean by electromagnetic induction?

Electromagnetic induction is a current produced due to EMF or voltage production in a constantly changing magnetic field.

What is electromagnetic induction, and how does it work?

Electromagnetic induction is a current produced due to EMF or voltage production in a constantly changing magnetic field. When a magnet is moved through a current containing a coil, it generates an induced voltage.

What is the use of electromagnetic induction?

It is used for a variety of purposes like AC generators, electrical transformers, etc.

What is the basic principle of electromagnetic induction?

The basic principle of Electromagnetic induction is Faraday’s law that states “that a voltage is induced in a circuit whenever relative motion exists between a conductor and a magnetic field and that the magnitude of this voltage is proportional to the rate of change of the flux.”

What are the two laws of electromagnetic induction?

The first law states that “A voltage is induced in a circuit whenever relative motion exists between a conductor and a magnetic field and that the magnitude of this voltage is proportional to the rate of change of the flux.”

The second law states, “the magnitude of EMF or voltage induced in the coil is equal to the rate of change of flux that linkages with the coil. The coil’s flux linkage is the product of the number of turns in the coil and flux associated with the coil.

Wanna learn a little more about this? Would you also like examples? You can check out our MSVgo app to better understand electromagnetic induction concepts with videos and interactive methods!

High School Physics

  • Alternating Current
  • Atoms
  • Communication Systems
  • Current Electricity
  • Dual nature of Radiation and Matter
  • Electric Charges and Fields
  • Electricity
  • Electromagnetic Induction
  • Electromagnetic Waves
  • Electron Beams and Radioactivity
  • Electrons and Photons
  • Electrostatic Potential and Capacitance
  • Fluid Pressure
  • Force and Acceleration
  • Force And Laws Of Motion
  • Gravitation
  • Internal Energy
  • Kinetic Theory
  • Law of motion
  • Light – Reflection And Refraction
  • Magnetic Effects Of Electric Current
  • Magnetism and Matter
  • Management Of Natural Resources
  • Mechanical properties of Fluids
  • Mechanical properties of Solids
  • Motion
  • Motion in a plane
  • Motion in a straight line
  • Moving Charges and Magnetism
  • Nuclear Energy
  • Nuclei
  • Oscillations
  • Our Environment
  • Paths of Heat
  • Physical world
  • Ray optics and optical instruments
  • Semiconductor Devices
  • Semiconductor Electronics: Materials, Devices and Simple Circuits
  • Simple Machines
  • Sound
  • Sources Of Energy
  • Specific and Latent Heats
  • Spherical Mirrors
  • Static Electricity
  • Systems of Particles and Rotational motion
  • Thermal properties of matter
  • Thermodynamics
  • Units and Measurement
  • Vectors, Scalar Quantities and Elementary Calculus
  • Wave Optics
  • Waves
  • Work, Power and Energy

High School Chemistry

  • Acids, Bases and Salts
  • Alcohols, Phenols and Ethers
  • Aldehydes, Ketones and Carboxylic Acids
  • Aliphatic and Aromatic Hydrocarbons
  • Alkyl and Aryl Halides
  • Amines
  • Analytical Chemistry 
  • Atomic Structure
  • Atoms And Molecules
  • Basic concepts of Chemistry
  • Biomolecules
  • Carbon And Its Compounds
  • Carboxylic acids and Acid Derivatives
  • Chemical Bonding and Molecular Structures
  • Chemical Energetics
  • Chemical Equilibria
  • Chemical Kinetics
  • Chemical Reactions And Equations
  • Chemical Reactions and Their Mechanisms
  • Chemistry in Everyday Life
  • Chemistry of p-Block elements
  • Chemistry of Transition and Inner Transition
  • Classification of Elements
  • Coordination Compounds
  • Cyanide, Isocyanide, Nitro compounds and Amines
  • Electrochemistry
  • Electrolysis
  • Elements, Compounds and Mixtures
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  • Equilibrium
  • Ethers and Carbonyl compounds
  • Haloalkanes and Haloarenes
  • Hydrocarbons
  • Hydrogen
  • Ideal solutions
  • Introduction to Organic Chemistry
  • Ionic equilibria
  • Matter
  • Matter Around Us
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  • Metallurgy
  • Metals And Non-Metals
  • Mole Concept and Stoichiometry
  • Natural Resources
  • Organic Chemistry – Basic Principles
  • Periodic Classification of Elements
  • Physical and Chemical Changes
  • Physical and Chemical Properties of Water
  • Polymers
  • Preparation, Properties and Uses of Compounds
  • Principles and Processes of Isolation of Elements
  • Redox Reactions
  • Relative Molecular Mass and Mole
  • States of Matter
  • Structure Of The Atom
  • Study of Compounds
  • Study of Gas Laws
  • Study of Representative Elements
  • Surface Chemistry
  • The d-block and f-block elements
  • The Gaseous State
  • The p-Block Elements
  • The Periodic Table
  • The s-Block Elements
  • The Solid State
  • Thermodynamics

High School Biology

  • Absorption and Movement of Water in Plants
  • Adolescent Issues
  • Anatomy of Flowering Plants
  • Animal Kingdom
  • Bacteria and Fungi-Friends and Foe
  • Biodiversity and Conservation
  • Biofertilizers
  • Biological Classification
  • Biomedical Engineering
  • Biomolecules
  • Biotechnology and its Applications
  • Biotic Community
  • Body Fluids and Circulation
  • Breathing and Exchange of Gases
  • Cell – Unit of Life
  • Cell Cycle and Cell Division
  • Cell Division and Structure of Chromosomes
  • Cell Reproduction
  • Cellular Respiration
  • Chemical Coordination and Integration
  • Circulation
  • Control And Coordination
  • Crop Improvement
  • Digestion and Absorption
  • Diversity In Living Organisms
  • Ecosystem
  • Environmental Issues
  • Excretory Products and their Elimination
  • Flowering Plants
  • Genes and Chromosomes
  • Health and Diseases
  • Health and Its Significance
  • Heredity And Evolution
  • Heredity and Variation
  • How Do Organisms Reproduce?
  • Human Diseases
  • Human Eye And Colourful World
  • Human Health and Disease
  • Human Population
  • Human Reproduction
  • Hygiene
  • Improvement In Food Resources
  • Integumentary System- Skin
  • Kingdom Fungi
  • Kingdom Monera
  • Kingdom Protista
  • Life Processes
  • Locomotion and Movement
  • Microbes in Human Welfare
  • Mineral Nutrition
  • Molecular Basis of Inheritance
  • Morphology of Flowering Plants
  • Neural Control And Coordination
  • Nutrition in Human Beings
  • Organism and Population
  • Photosynthesis
  • Photosynthesis in Higher Plants
  • Plant Growth and Development
  • Plant Kingdom
  • Pollination and Fertilization
  • Pollution; Sources and its effects
  • Principles of Inheritance and Variation
  • Reproduction and Development in Angiosperms
  • Reproduction in Organisms
  • Reproductive Health
  • Respiration in Human Beings
  • Respiration in Plants
  • Respiratory System
  • Sexual Reproduction in Flowering Plants
  • Strategies for Enhancement in Food Production
  • Structural Organisation in Animals
  • Structural Organisation of the Cell
  • The Endocrine System
  • The Fundamental Unit Of Life
  • The Living World
  • The Nervous System and Sense Organs
  • Tissues
  • Transpiration
  • Transport in Plants

High School Math

  • Algebra – Arithmatic Progressions
  • Algebra – Complex Numbers and Quadratic Equations
  • Algebra – Linear Inequalities
  • Algebra – Pair of Linear Equations in Two Variables
  • Algebra – Polynomials
  • Algebra – Principle of Mathematical Induction
  • Algebra – Quadratic Equations
  • Binomial Theorem
  • Calculus – Applications of Derivatives
  • Calculus – Applications of the Integrals
  • Calculus – Continuity and Differentiability
  • Calculus – Differential Equations
  • Calculus – Integrals
  • Geometry – Area
  • Geometry – Circles
  • Geometry – Conic Sections
  • Geometry – Constructions
  • Geometry – Introduction to Euclid’s Geometry
  • Geometry – Three-dimensional Geometry
  • Geometry – Lines and Angles
  • Geometry – Quadrilaterals
  • Geometry – Straight Lines
  • Geometry – Triangles
  • Linear Programming
  • Matrices and Determinants
  • Mensuration – Areas
  • Mensuration – Surface Areas and Volumes
  • Number Systems
  • Number Systems – Real Numbers
  • Permutations and Combinations
  • Probability
  • Sequence and Series
  • Sets and Functions
  • Statistics 
  • Trignometry – Height and Distance
  • Trignometry – Identities
  • Trignometry – Introduction

Middle School Science

  • Acids, Bases And Salts
  • Air and Its Constituents
  • Basic Biology
  • Body Movements
  • Carbon and Its Compounds
  • Cell – Structure And Functions
  • Changes Around Us
  • Chemical Effects Of Electric Current
  • Chemistry in Your Life
  • Coal And Petroleum
  • Combustion And Flame
  • Components Of Food
  • Conservation Of Plants And Animals
  • Crop Production And Management
  • Electric Current And Its Effects
  • Electricity And Circuits
  • Elements and Compounds
  • Fibre To Fabric
  • Food production and management
  • Force And Pressure
  • Forests: Our Lifeline
  • Friction
  • Fun With Magnets
  • Garbage In, Garbage Out
  • Getting To Know Plants
  • Health and Hygiene
  • Heat
  • Hydrogen
  • Life Processes: Nutrition in Animals and Plants
  • Light, Shadows And Reflections
  • Materials: Metals And Non-Metals
  • Matter and Its States
  • Metals and Non-metals
  • Micro Organisms: Friend And Foe
  • Motion And Measurement Of Distances
  • Motion And Time
  • Nutrition In Animals
  • Nutrition In Plants
  • Organization in Living Things
  • Our Environment
  • Physical And Chemical Changes
  • Pollution and conservation
  • Pollution Of Air And Water
  • Reaching The Age Of Adolescence
  • Reproduction In Animals
  • Reproduction In Plants
  • Respiration In Organisms
  • Rocks and Minerals
  • Separation Of Substances
  • Simple Machines
  • Soil
  • Some Natural Phenomena
  • Sorting Materials Into Groups
  • Sound
  • Stars And The Solar System
  • Structure of Atom
  • Synthetic Fibers And Plastics
  • The Living Organisms And Their Surroundings
  • Transfer of Heat
  • Transformation of Substances
  • Transportation In Animals And Plants
  • Universe
  • Waste-water Story
  • Water: A Precious Resource
  • Weather, Climate And Adaptations Of Animals To Climate
  • Winds, Storms And Cyclones

Middle School Math

  • Addition
  • Area and Its Boundary
  • Boxes and Sketches
  • Data Handling
  • Fun With Numbers
  • Heavy and Light
  • How Many
  • Long And Short
  • Mapping
  • Measurement
  • Money
  • Multiplication and Factors
  • Multiply and Divide
  • Numbers
  • Parts and Wholes
  • Pattern Recognition
  • Patterns
  • Play With Patterns
  • Rupees And Paise
  • Shapes And Angles
  • Shapes And Designs
  • Shapes and Space
  • Similarity
  • Smart Charts
  • Squares
  • Subtraction
  • Tables And Shares
  • Tenths and Hundredths
  • Time
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