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Nature of Electricity
Drift Velocity Drift Current and Electron Mobility
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Electrical Conductance Conductivity of Metal Semiconductor and Insulator | Band Theory
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Ideal Dependent Independent Voltage Current Source
Series Parallel Battery Cells
Single and Multi Mesh Analysis
Kirchhoff Current Law and Kirchhoff Voltage Law
Superposition Theorem
Reciprocity Theorem
Compensation Theorem
Electric Power Single and Three Phase Power Active Reactive Apparent
Types of resistor Carbon Composition and Wire Wound Resistor
Varistor Metal Oxide Varistor is nonlinear Resistor
Principle of Electrolysis of Copper Sulfate Electrolyte
Construction of Lead Acid Battery
Voltaic Cell
Norton Theorem | Norton Equivalent Current and Resistance
Maximum Power Transfer Theorem
Working of Lead Acid Battery | Lead Acid Secondary Storage Battery
Fleming Left Hand rule and Fleming Right Hand rule
Ohms Law | Equation Formula and Limitation of Ohms Law
Electrical DC Series and Parallel Circuit
Ionization Process and Definition
Faraday First and Second Laws of Electrolysis
Applications of Electrolysis Electroplating Electroforming Electrorefining
Resistances in Series and Resistances in Parallel
Delta - Star transformation | Star - Delta Transformation
Tellegen Theorem
Thevenin Theorem and Thevenin Equivalent Voltage and Resistance
Vector Algebra | Vector Diagram
Wheatstone Bridge Circuit Theory and Principle
Vector Diagram | Three Phase Vector Diagram
Static Electric Field | Electrostatic Induction | Electric Field Strength
Joules Law of Heating
Gauss Theorem
Alkaline Batteries
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Three Phase Circuit | Star and Delta System
Potentiometer Working Principle of Potentiometer
Lenz Law of Electromagnetic Induction
Seebeck Effect and Seebeck Coefficient
Faraday Law of Electromagnetic Induction
RL Series Circuit
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RL Circuit Transfer Function Time Constant RL Circuit as Filter
Battery | History and Working Principle of Batteries
RL Parallel Circuit
Series RLC Circuit
Coulombs Law | Explanation Statement Formulas Principle Limitation of Coulomb’s Law
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Aluminum Air Battery | Experiment Reaction Equations Uses
Kelvin Bridge Circuit | Kelvin Double Bridge
Magnetic Field and Magnetic Circuit | Magnetic Materials
Biot Savart Law
What is Capacitor and Capacitance? Types of Capacitors
Zinc Carbon Battery |Types of Zinc Carbon Battery | Advantages and Disadvantages
Mercuric Oxide Battery | Chemistry Construction Advantages Uses
Variable Resistors | Defination, Uses and Types of Variable Resistors
Electric Lamp | Types of Electric Lamp
What is Inductor and Inductance | Theory of Inductor
Charging of Battery and Discharging of Battery
Magnesium Battery | Chemistry Construction of Magnesium Battery

Faraday Law of Electromagnetic Induction

Under Basic Electrical In 1831, Michael Faraday, an English physicist gave one of the most basic laws of electromagnetism called Faraday's law of electromagnetic induction. This law explains the working principle of most of theelectrical motors, generators, electrical transformers and inductors . This law shows the relationship between electric circuit and magnetic field. Faraday performs an experiment with a magnet and coil. During this experiment, he found how emf is induced in the coil when flux linked with it changes. He has also done experiments in electro-chemistry and electrolysis.

Faraday's Experiment

RELATIONSHIP BETWEEN INDUCED EMF AND FLUX Faraday's law In this experiment, Faraday takes a magnet and a coil and connects a galvanometer across the coil. At starting, the magnet is at rest, so there is no deflection in the galvanometer i.e needle of galvanometer is at the center or zero position. When the magnet is moved towards the coil, the needle of galvanometer deflects in one direction. When the magnet is held stationary at that position, the needle of galvanometer returns back to zero position. Now when the magnet is moved away from the coil, there is some deflection in the needle but in opposite direction and again when the magnet becomes stationary, at that point with respect to coil, the needle of the galvanometer returns back to the zero position. Similarly, if magnet is held stationary and the coil is moved away and towards the magnet, the galvanometer shows deflection in similar manner. It is also seen that, the faster the change in the magnetic field, the greater will be the induced emf or voltage in the coil.
Position of magnetDeflection in galvanometer
Magnet at restNo deflection in galvanometer
Magnet moves towards the coilDeflection in galvanometer in one direction
Magnet is held stationary at same position (near the coil)No deflection in galvanometer
Magnet moves away from the coilDeflection in galvanometer but in opposite direction
Magnet is held stationary at same position (away from the coil)No deflection in galvanometer

CONCLUSION: From this experiment, Faraday concluded that whenever there is relative motion between conductor and a magnetic field, the flux linkage with a coil changes and this change in flux induces a voltage across a coil.

Michael Faraday formulated two laws on the basis of above experiments. These laws are called Faraday's laws of electromagnetic induction.

Faraday's Laws

Faraday's First Law

Any change in the magnetic field of a coil of wire will cause an emf to be induced in the coil. This emf induced is called induced emf and if the conductor circuit is closed, the current will also circulate through the circuit and this current is called induced current. Method to change magnetic field: 1. By moving a magnet towards or away from the coil

2. By moving the coil into or out of the magnetic field.

3. By changing the area of a coil placed in the magnetic field

4. By rotating the coil relative to the magnet.

Faraday's Second Law

It states that the magnitude of emf induced in the coil is equal to the rate of change of flux that linkages with the coil. The flux linkage of the coil is the product of number of turns in the coil and flux associated with the coil.

Faraday Law Formula

Faraday's law Consider a magnet approaching towards a coil. Here we consider two instants at time T1 and time T2.

Flux linkage with the coil at time, T1 = NΦ1 Wb

Flux linkage with the coil at time, T2 = NΦ2 wb

Change in flux linkage = N(Φ2 - Φ1)

Let this change in flux linkage be, Φ = Φ2 - Φ1

So, the Change in flux linkage = NΦ

Now the rate of change of flux linkage = NΦ / t

Take derivative on right hand side we will get

The rate of change of flux linkage = NdΦ/dt

But according to Faraday's law of electromagnetic induction, the rate of change of flux linkage is equal to induced emf.

Considering Lenz's Law.

Where flux Φ in Wb = B.A

B = magnetic field strength


• By increasing the number of turns in the coil i.e N- From the formulae derived above it is easily seen that if number of turns of coil is increased, the induced emf also gets increased.

• By increasing magnetic field strength i.e B surrounding the coil- Mathematically if magnetic field increases, flux increases and if flux increases emf induced will also get increased. Theoretically, if the coil is passed through a stronger magnetic field, there will be more lines of force for coil to cut and hence there will be more emf induced.

• By increasing the speed of the relative motion between the coil and the magnet - If the relative speed between the coil and magnet is increased from its previous value, the coil will cut the lines of flux at a faster rate, so more induced emf would be produced.

Applications of Faraday Law

Faraday law is one of the most basic and important laws of electromagnetism . This law finds its application in most of the electrical machines, industries and medical field etc.

Electrical Transformers It is a static ac device which is used to either step up or step down voltage or current. It is used in generating station, transmission and distribution system. The transformer works on Faraday's law.

• Electrical Generators The basic working principle of electrical generator is Faraday's law of mutual induction. Electric generator is used to convert mechanical energy into electrical energy.

• Induction Cookers The Induction cooker, is a most fastest way of cooking. It also works on principle of mutual induction. When current flows through the coil of copper wire placed below a cooking container, it produces a changing magnetic field. This alternating or changing magnetic field induces an emf and hence the current in the conductive container, and we know that flow of current always produces heat in it.

• Electromagnetic Flow Meters It is used to measure velocity of blood and certain fluids. When a magnetic field is applied to electrically insulated pipe in which conducting fluids are flowing, then according to Faraday's law, an electromotive force is induced in it. This induced emf is proportional to velocity of fluid flowing .

• Form the bases of Electromagnetic Theory Faraday's idea of lines of force is used in well known Maxwell's equations. According to Faraday's law, change in magnetic field gives rise to change in electric field and the converse of this is used in Maxwell's equations.

• Musical Instruments It is also used in musical instruments like electric guitar, electric violin etc.

Faraday's Law-Video

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