Induced Electromotive Force and Current: Definition, Faraday’s Law

Education Journalist | Study Abroad Strategy Lead

Induced electromotive force and current take place inside the magnetic field and the current is generated by changing the magnetic field. Faraday's law of electromagnetic Induction is associated with induced electromotive force and current. Induced electromagnetic force is a voltage that is created when magnetic flux is passed through a coil. An electrical effect is created on the opposite side of coil when a wave of current starts to flow in the wire.

Also read: Lenz’s law

Table of Content

Induced Electromotive Force
Electromotive Force
Faraday’s Law
Things to Remember
Previous Year questions
Sample Questions

Key Terms: Force, Current, Faraday’s Law, Magnetic Field, Magnetic Flux, Electromotive Force, Induced Electromotive Force

Induced Electromotive Force

[Click Here for Sample Questions]

Current can be induced in the coil by altering the magnetic field. Change in the magnetic field causes the current to flow. When magnetic flux changes while passing through a loop, an induced electromotive force is created. Induced electromotive force is used in transformers, galvanometers, and generators.

Induced Electromotive Force

Induced Electromotive Force

Read More: Magnetic Field in A Solenoid

Electromotive Force

[Click Here for Previous Year Questions]

When change in the magnetic field of an electrochemical cell produces electric potential, it is known as electromotive force or EMF. Electromotive force is work done on a unit electric charge because, in order to convert energy from one form to another, a battery or generator is used where one terminal is negatively charged whereas the other one is positively charged.

Electromotive force is used in electromagnetic flow meters.

Electromotive force is expressed as:

(ε) = v + lr

Where,

v = voltage

l = current

r = internal resistance

Electromotive Force

Electromotive Force

Also Read:

Related Articles
Uses of Inductor	Transformers	Electromagnets
Electromagnetic Field	Motional emf	Experiment faraday henry

Faraday’s Law

[Click Here for Sample Questions]

Faraday’s law of electromagnetic induction consists of two laws. Induced electromotive force in a conductor is described in the first law and the second law deals with the amount of electromagnetic force produced in the conductor.

According to Faraday's first law of electromagnetic induction, an electromotive force is induced when a conductor is placed in a magnetic field that can be changed. Induced current is produced in a conductor if it is closed. Second Faraday's law of electromagnetic induction states that induced electromagnetic force in a coil is equivalent to the rate of change of flux.

ε = - N ΔΦΔt

Where, ε = induced voltage/ electromotive force

ΔΦ = change in the magnetic flux

Δt = change in time

N = number of loops

Faraday’s Law of Electromagnetic Induction Detailed Explanation

Faraday’s Laws of Electromagnetic Induction Video Explanation

Read More: Electromagnetism

Things to Remember

The change in the flux of the conductor or coil induced electromotive force.
Electromotive force is measured in volt.
If electromotive force is obtained in a moving electric conductor, in the presence of a magnetic field, it is known as motional electromotive force.
Emf can be induced either through change in magnetic flux in the circuit or through motion of conductor in the magnetic field.
Concept of Lorentz force deals with the concept of induced electromotive force and current.
Induced emf gives rise to a generation of potential difference in the coil because of change in magnetic flux.
Induced emf is also known by the names of electromotive force induction, electromagnetic induction, and induced electromotive force.

Also Read:

Chapter Related Articles
Faraday Constant	Electromagnetic Damping	Uses of Inductor
Lenz’s Law and Conservation of Energy	AC Generator	Types of Generators
Magnetic Induction Formula	Magnetic Flux	Energy Consideration

Previous Year Questions

Sample Questions

Ques. What is the dimension of electromotive force? (2 Marks)

Ans. Dimension of electromotive force is M¹L²T^-3I^-1. The ratio of work done on unit charge is known as EMF.

Emf = joules coulombs

Electromotive force is calculated in Volts.

Ques. How does the electromotive force affect the strings of an electric guitar? (2 Marks)

Ans. Electromotive force is created inside the coil when the strings of the electric guitar vibrate. The vibration of the guitar gives rise to the magnetization which is present in the string. The input of the guitar is connected to the two ends of the coil which are connected to the speaker.

Ques. What happens when a magnet is moved rapidly in a static coil? (2 Marks)

Ans. Because of the increase in the rate of change in the magnetic field, the induced electromotive force also increases. There is a change in the magnetic flux near the coil which depends on the rate of change in the magnetic field.

Ques. Differentiate between EMF and terminal voltage. (3 Marks)

Ans.

Electromotive force	Terminal voltage
The maximum potential difference in the presence of a battery when there is no flow of current	The potential difference across the terminal keeping the circuit on.
It is measured by a potentiometer	It is measured by a voltmeter

Ques. What are some of the common applications of Faraday’s law? (2 Marks)

Ans. Faraday’s law is applied in :

Transformers
Induction cooker follows principle of mutual induction
Velocity of the fluid is recorded when an electromotive force is induced in an electromagnetic flowmeter
Electric guitar and electric violin

Ques. What is magnetic flux? (2 Marks)

Ans. Number of magnetic field lines passing through a closed surface is known as magnetic flux. The area under consideration depends on the direction of the magnetic field. It is usually measured in flux meters and its SI unit is weber (wb). The formula is:

Φ_B = B.A = BA cos θ

Where,

Φ_B = magnetic flux

B= magnetic field

A = area

θ = the angle at which the field line passes

Ques. What are the factors on which the induced electromotive force depends? (2 Marks)

Ans. The factors on which the electromotive force depends are:

Speed of the magnet moving into or out of the coil
Cross-sectional area of the coil
Magnetic strength
Number of loops of wire

Ques. How to change the magnetic field intensity in a closed-loop? (2 Marks)

Ans. Intensity of magnetic field in a closed loop can be changed by:

Rotation of the coil according to the magnet
Movement of the coil in or out of the magnetic field
Reducing or increasing the distance between the magnet and the coil
Altering the area of the coil placed inside the magnetic field.

Ques. List some of the differences between potential difference and electromotive force. (3 Marks)

Ans.

Potential difference	Electromotive difference
It is represented by V	It is represented by E
It changes over time	It remains unchanged
Defined as The energy which is lost as the unit charge pass through the component	Defined as work done on a unit charge
The resistance between the two points are taken into consideration	Exists without circuit resistance
The only electric field is induced	It gives rise to electrical, magnetic, and gravitation field

For Latest Updates on Upcoming Board Exams, Click Here: https://t.me/class_10_12_board_updates

Check-Out:

PCMB Study Guides
NCERT Solutions for Class 12 Physics	Class 12 Physics Notes	Formulas in Physics
Topics for Comparison in Physics	Choice-based questions in physics	Topics in relation to physics
Physics Study Notes	Class 12 Physics Book PDF	Class 12 Physics Practicals
Important Derivations in Physics	SI units in Physics	Important Physics Constants and Units
Class 12 Physics Syllabus	Mendeleev's Periodic Table	NCERT Solutions for Class 12 Biology
NCERT Solutions for Class 12 English	NCERT Solutions for Class 11 Chemistry	Class 12 Chemistry Practicals
Class 12 Chemistry Notes	Important Chemical Reactions	Class 12 Maths Notes
Class 12 PCMB Notes	NCERT Class 12 Biology Book	NCERT Class 12 Maths Book
NCERT Class 12 Textbooks	NCERT Solutions for Class 11 Maths	NCERT Solutions for Class 11 Physics
NCERT Solutions for Class 12 Maths	NCERT Solutions for Class 11 Biology	NCERT Solutions for Class 11 English
NCERT Class 11 Chemistry Book	NCERT Class 11 Physics Book	NCERT Class 11 Biology Book
Class 11 Notes	Important Maths Formulas	Important Chemistry Formulas
Class 11 PCMB Syllabus	Chemistry Study Notes	Biology Study Notes
Periodic Table in Chemistry	Important Chemical Reactions	Comparison topics in Chemistry
Comparison Topics in Maths	Biology MCQs	Important Named Reactions
Maths MCQs	Comparison Topics in Biology	Chemistry MCQs

Induced Electromotive Force and Current: Definition, Faraday’s Law

Induced Electromotive Force

Electromotive Force

Faraday’s Law

Faraday’s Law of Electromagnetic Induction Detailed Explanation

Things to Remember

Previous Year Questions

Sample Questions

CBSE CLASS XII Related Questions

1.
Assertion : In Young’s double-slit experiment, the fringe width for dark and bright fringes is the same. Reason (R): Fringe width is given by \( \beta = \frac{\lambda D}{d} \), where symbols have their usual meanings.

2.
Assertion : Induced emf produced in a coil will be more when the magnetic flux linked with the coil is more. Reason (R): Induced emf produced is directly proportional to the magnetic flux.

3.
Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

4.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

5.
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

6.
A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is rotated through an angle of 60° in 0.2 s. The value of emf induced in the loop will be:

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

Induced Electromotive Force and Current: Definition, Faraday’s Law

Induced Electromotive Force

Electromotive Force

Faraday’s Law

Faraday’s Law of Electromagnetic Induction Detailed Explanation

Things to Remember

Previous Year Questions

Sample Questions

CBSE CLASS XII Related Questions

1.Assertion : In Young’s double-slit experiment, the fringe width for dark and bright fringes is the same. Reason (R): Fringe width is given by \( \beta = \frac{\lambda D}{d} \), where symbols have their usual meanings.

2.Assertion : Induced emf produced in a coil will be more when the magnetic flux linked with the coil is more. Reason (R): Induced emf produced is directly proportional to the magnetic flux.

3.Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

4.In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

5.The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

6.A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is rotated through an angle of 60° in 0.2 s. The value of emf induced in the loop will be:

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
Assertion : In Young’s double-slit experiment, the fringe width for dark and bright fringes is the same. Reason (R): Fringe width is given by \( \beta = \frac{\lambda D}{d} \), where symbols have their usual meanings.

2.
Assertion : Induced emf produced in a coil will be more when the magnetic flux linked with the coil is more. Reason (R): Induced emf produced is directly proportional to the magnetic flux.

3.
Assertion : Photoelectric effect is a spontaneous phenomenon. Reason (R): According to the wave picture of radiation, an electron would take hours/days to absorb sufficient energy to overcome the work function and come out from a metal surface.

4.
In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.

5.
The magnetic field in a plane electromagnetic wave travelling in glass (\( n = 1.5 \)) is given by \[ B_y = (2 \times 10^{-7} \text{ T}) \sin(\alpha x + 1.5 \times 10^{11} t) \] where \( x \) is in metres and \( t \) is in seconds. The value of \( \alpha \) is:

6.
A square loop of side 0.50 m is placed in a uniform magnetic field of 0.4 T perpendicular to the plane of the loop. The loop is rotated through an angle of 60° in 0.2 s. The value of emf induced in the loop will be: