# CBSE Class 12 Physics Revision Notes Chapter 6

## Class 12 Physics Chapter 6 Notes – Electromagnetic Induction

Physics is an important subject for high school students and also for students preparing for any competitive exams for other science oriented courses.

Extramarks is one of the most reliable online platforms for students to study science oriented subjects. Class 12 Physics Chapter 6 Notes is helpful for students preparing for school or competitive levels examinations like JEE or NEET. These Notes are quick to read and can be revised before examinations. The subject experts prepare the Notes at Extramarks, and students can avail this benefit  only by registering with the Extramarks. Students are advised to read the NCERT book thoroughly. And after that, they can go through these Notes to better understand the concepts involved in the chapter in a better way.

### Key Topics Covered In Class 12 Physics Chapter 6 Notes

Class 12 Physics Chapter 6 Notes cover all the concepts around magnetic & electrical Induction, motional force, currents arising due to it & the construction, and the working of generators/ motors.

Given below there is a  summary of key topics covered in our CBSE Class 12 Physics Chapter 6 Notes.

Magnetic Flux:

As per the Class 12 Physics Chapter 6 Notes, Magnetic flux in any area equals the total number of magnetic field lines of force passing through that area.

{source: https://spark.iop.org/magnetic-fluxl name: magnetic flux}

Net flux through an area A having, under the magnetic influence of B, can be given as

Magnetic flux = ɸ = B. dA = BAcosΘ

Where, B = magnetic flux through an area

A = area under consideration

= angle between area vector and magnetic field vector.

• Case 1

When the value of = 0

ɸ = BA

• Case 2

When the value of = 90

ɸ = 0

Some important Properties as covered in our Class 12 Physics Chapter 6 Notes:

• Magnetic flux is denoted by ɸ.
• Flux is a scalar quantity.
• The SI unit of magnetic flux is Weber (Wb).
• The CGS unit of magnetic flux is maxwell or gauss.
• 1 Wb = 108 gauss.
• The dimensional formula of flux is [ ɸ ] = [M L2 T-2 A-2].

Electromagnetic Induction:

A fluctuating magnetic flux arises in a closed coil when a changing current is put across it. An emf is induced in the coil as a result of this flow. It generates an induced current as a result of the induced emf. Electromagnetic Induction is the phenomenon of creating induced emf or current due to changing flux.

Students are recommended to register on Extramarks’ website and access coursework and study resources such as Class 12 Physics Chapter 6 Notes, CBSE Extra Questions, CBSE Important Questions, etc. for a detailed explanation on electromagnetic induction.

There are two laws under Faraday’s Law of EMI.

• Law 1

Law 1 states that whenever a change of magnetic flux is linked with any circuit, an emf is induced, which lasts as long as the change in magnetic flux continues.

• Law 2

According to the Second Law, the magnitude of emf induced is directly proportional to the rate of change of magnetic flux.

∝ dɸ / dt

Therefore, induced emf = e = N (dɸ / dt)

Where N = number of turns pf coil

Induced Current

Induced current = i = e/R = N/R (dɸ / dt)

Induced Charge:

Induced charge = dq = i dt = N/R (dɸ)

Induced charge is independent of time

Induced power = P = e2/R = N2/R (dɸ / dt)2

How to produce induced EMF:

EMF or electromotive force is induced in any circuit whenever there is a change in magnetic flux. But, this emf can be induced in many ways.

As magnetic flux = ɸ = BAcosΘ

Hence, flux ɸ can be changed when any B, A or  is altered.

Therefore, the following ways can be used to induce EMF:

• By changing/ adjusting magnetic field B.
• By changing the area under consideration, A.

The area can be altered by stretching, shrinking or modifying the coil’s shape.

• By changing the angle .

This can be done by modifying the surface’s area and the magnetic field’s relative orientation.

Lenz’s Law:

According to Lenz’s Law, the direction of induced emf or current opposes the change in magnetic flux produced by it.

That is, e = -N (dɸ / dt)

Where N = number of turns

This Law is based on the conservation of energy.

Below is a short overview of how the magnetic field and magnetic force change according to the position of the magnet and the direction of the induced current. To get a better understanding of this law we recommend students to refer to our Class 12 Physics Chapter 6 Notes.

 Position of magnet Towards the coil Away from coil Towards the coil Away from coil The direction of induced current Anticlockwise Clockwise Clockwise AntiClockwise The behaviour of the face of the coil North pole South pole South pole North pole Type of magnetic force Repulsive force Attractive force Repulsive force Attractive force The magnetic field linked with the coil Increases Decreases Increases Decreases

Students are recommended the Extramarks website and access coursework and study resources such as Class 12 Physics Chapter 6 Notes, CBSE Extra Questions, CBSE Important Questions, etc. for a more detailed explanation on Lenz’s Law.

Eddy Current:

As stated in the Class 12 Physics Chapter 6 Notes, Eddy currents are small circles of electric currents induced in a large piece of conductor whenever there is a change in magnetic flux. Eddy current has enormous magnitudes. They usually heat the conductor due to the low resistance of the bulk conductor.

The Lenz law of electromagnetic Induction, in which the current twirls in a way that forms a magnetic field, is explained in detail in Chapter 6 of the Physics Class 12 Notes. Eddy currents are of the opposing type, which results in a considerable energy loss. This current heats kinetic energy or another important energy form.

Some important Properties:

• Eddy currents are circulating currents similar to water eddies.
• It is also named ‘Foucault current’ after Foucault’s experimental hypothesis.
• The generation of eddy current results in loss of electrical energy in the form of heat.

Students are suggested to refer to the Extramarks’ website and access coursework and study resources such as Class 12 Physics Chapter 6 Notes, CBSE Extra Questions, CBSE Important Questions, etc. for a more detailed explanation on Eddy currents.

Applications of Eddy currents:

As stated in the Class 12 Physics Chapter 6 Notes, The Loss of Energy Can Be Useful for Specific Functions Like brakes in train. . An eddy current creates a magnetic field around the metal wheels when the braking system is activated. This magnetic interaction is linked to an applied field that reduces the train’s speed. The braking force is reduced when the wheels move faster, resulting in a smooth stopping motion.

A permanent centre made of non-magnetic metallic materials is found only in a few galvanometers. An oscillating coil is found to impact Eddy’s current, which brings motion to a halt.

Furthermore, by melting layers of metal, an induction furnace aids in the formation of alloys. The eddy current that forms within metals also generates a lot of heat.

Eddy currents are usually avoided in any environment. However, as heat is produced from the kinetic energy from eddy losses, they are used in several cases given as follows:

• They are used in braking in trains, roller coasters, electric saws and drills.
• Eddy currents are widely used in induction cooking, and induction furnaces are used to heat metals to their melting points for welding, brazing etc.
• By using eddy currents, an adjustable speed drive can be achieved with the help of a feedback controller.

Induced Charge Flow:

A charge flows through the circuit when a current is induced due to changing magnetic flux. The net charge flowing through the circuit can be denoted as:

q = i dt = 1/R  dɸ/dt  dt = 1/R

q = Δɸ / R and   q = N Δɸ / R where N = number of turns

Induced Electric Field:

As explained in our Class 12 Physics Chapter 6 Notes the induced electric field is non-conservative and non-electrostatic. The field lines are concentric and have circular closed waves.

A time-varying magnetic field, dB dt, produces an induced electric field in all surrounding space. The induced electric area is directly proportional to induced emf.

Therefore, e = -(dɸ / dt)

The above equation is the integral form of Faraday’s Law of EMI.

Motional Emi in Loop by Generated Area:

For inducing EMF in a generated area, a conducting rod passes along two parallel conducting rails. The developed area is the area swept by a conductor in a magnetic field while the rod moves.

The induced current from the motional EMI in the loop by generated area is given as:

i = e/R = BvI/R

Where i = induced current

E = induced emf

B = magnetic field

R = resistance of resistor

V = velocity

While moving the conductor rod, PQ experiences a magnetic force in a direction opposite to its motion. That magnetic force is given as,

Fm = Bil = B (Bvl/R)l = B2vl2/R

Similarly, when the conductor moves, power is dissipated. The power delivered by an external source is given as,

Pmech = Pext = dW/dt = Fext . v = (B2vl2/R)v = B2v2l2/R

Also, the rate of heat dissipation across the resistance is given as,

Pthermal = H/t = i2R = (Bvl/R)2 .R =  B2v2l2/R

Hence, it is clear that Pmech = Pthermal

Periodic EMI

Suppose a rectangular coil with N turns is placed in a magnetic field such that the magnetic field is perpendicular to the plane of the rectangular coil.

Having ⍵ its angular speed,

v = frequency of coil’s rotation,

R = resistance of the coil

Hence, a flux is linked to the coil due to uniform rotational motion, which is given as,

ɸ = NBA cosΘ = NBA cos⍵t

ɸ = ɸocos⍵t

where ɸo = NBA = maximum flux.

Induced EMF:

The emf induced changes in an aperiodic manner, which is called Periodic EMI.

Induced emf is given as, e = dɸ/dt = NBA⍵ sin⍵t

E = eo sin⍵t where eo = maximum emf = NBA⍵ = ɸo

Induced current:

At any time t, the induced current i is given as,

i = e/R = eo/R sin⍵t = io sin⍵t

Where io = maximum current or current amplitude

Inductance:

Whenever a current passing through a coil changes, the magnetic flux also changes. Hence according to Faraday’s Law of electromagnetic Induction, an emf is induced in the coil that opposes the cause changing it.

The phenomenon is called self-induction, and the emf produced is called back-emf. The corresponding current produced is induced wind.

Inductance is a property that opposes any change in the circuit’s current. Inductance is an intrinsic feature of electrical circuits. The inductance of a straight wire carrying electricity without an iron portion will always be lower.

This topic is found to be difficult for many students. We suggest students to refer to our Class 12 Physics Chapter 6 Notes where our subject experts have explained these difficult concepts in easy language.

Self-inductance:

Self-inductance is a phenomenon where an emf is induced by changing the current in the coil.

Some important Properties

• L deNotes the inductance of self-inductance.
• The SI unit of inductance is Henry and denoted by H.
• The dimensional formula of inductance is [ M L2 T-2 A-2 ].
• Coefficient of self induction = L = Nɸ /i.

Where N = number of turns of the coil

ɸ = magnetic flux

And i = current flowing through the coil.

Self-inductance for conductors

• Self inductance for circular coil is = L = µoN2A /2R.

Where r = radius of circular coil, N = number of turns, A = area of circular coil = πR2.

• Self-inductance of a solenoid = L = µoN2A /l.

Where l= length of solenoid, N = number of turns.

• Self-inductance for a square coil is L = 2√2 µoN2a / π.
• Energy stored in an inductor = 12LI².

Dependency of inductance:

• Self-inductance or L does not depend on the current flowing through the coil/conductor.
• Instead, L depends on the number of turns or N, area of cross-section A, and permeability of medium µ.
• Moreover, self-inductance or L only begins to show whenever there is a change in current.

Mutual inductance:

Whenever a change in current in a coil, the magnetic flux associated with the neighbouring coil also changes. Hence an emf is induced in the adjacent coil or circuit. This phenomenon is called mutual inductance.

The first coil where current changes are called the primary coil, whereas the second coil where emf is induced is called the secondary coil.

Some important Properties:

• M deNotes mutual inductance or the coefficient of mutual InductionInduction.
• The SI unit & dimensional formula of mutual induction / M is the same as that of self-inductance, L.

The two coils or circuits are in consideration for mutual InductionInduction.

Hence, N1 and N2 are the number of turns in 2 coils.

Similarly, the emf induced and the current flowing through them will be e1, e2, ɸ1, and ɸ2, respectively.

Since emf is induced in coil 2 due to the change in current in coil 1,

ɸ2 ∝ i1

Hence, ɸ2 = M i1 where M = coefficient of mutual InductionInduction.

According to Faraday’s Law of electromagnetic Induction, an emf is induced in a secondary coil due to a change in current in the first coil, which is given as,

e2 = -N22/dt

e2 = -M di2/dt

Dependence of mutual inductance:

• The coefficient of mutual Induction or M is dependent on the number of turns of both coils, N1 and N2, coefficient of self inductances of both the coils L1 and L2, area of cross-section of coils and magnetic permeability of medium present between the coils,  µ.
• Induction depends on the distance between two coils, d and orientation between the primary and secondary coil.

Relation between K, L and M:

Self-inductance for primary coil and secondary coil is L1 and L2, and M is the mutual inductance.

Then, the relation between mutual inductance and self-inductance is given as

M = KL1 L2

Where K = the coupling factor between the primary coil and secondary coil.

K = magnetic flux linked in secondary coil / magnetic flux linked in the primary coil.

Where the value of k ranges from 0 to1.

0 ≤ k ≥ 1

Mutual inductance for conductors

• Mutual inductance for two concentric coplanar circular coils,

M = π µo N1 N2 r2 2R

• Mutual inductance for two solenoids

M = µo N1 N2 Al

• Mutual inductance for two concentric coplanar square coils

M = µo 2 2 N1 N2 l2πL

Combination of Inductance

• In series

If two coils having self-inductance, L1 and L2, are kept in series and far away from each other, there is negligible mutual InductionInduction. The net self-inductance is given as,

Lnet = L1 +L2

And when these two coils are kept near to each other. Hence, net inductance is given as,

Lnet = L1 +L2  ± 2M

• In parallel:

If two coils with self-inductance, L1 and L2  are connected in parallel and placed far from each other. The net inductance is given as,

1L net = 1L1 + 1L2

Lnet = L1 L2L1 + L2

And if they are situated close to each other,

Lnet = L1 L2 – M2L1 + L2 ± 2M

 Cases When two coils are placed far from each other When two coils are near each other. When the current is in the same direction as that of winding.  Hence the flux assists each other. When two coils are near each other. When the current is in the opposite direction as that of winding.  Hence the flux assists each other. In series Lnet = L1 +L2 Lnet = L1 +L2  +2M Lnet = L1 +L2  – 2M In parallel Lnet = L1 L2L1 + L2 Lnet = L1 L2 – M2L1 + L2 +  2M Lnet = L1 L2 – M2L1 + L2 – 2M

Growth and decay in LR circuit:

The Lr circuit has pure inductor L and a resistor r in series, a battery, and a key closed. Here the current through the circuit grows exponentially until it reaches a maximum value or the steady-state. Hence when the circuit is opened from its steady state, the current diminishes exponentially.

The following parameters behave like this:

• Current:

The value of current at any time t, after the circuit is closed, is given as,

i = io = [1-eRt/L

Where io = imax = ER= steady state current

But, the value of current at any time t, after opening from the steady-state condition, is given as,

i= io eRt/L

• Time constant:

The time constant is defined as the period when the current in an inductive circuit rises to 63% of its maximum value. After opening an inductive circuit, the current falls to 37% of its maximum value during time continuous.

The time constant is given as,

𝜏 = LR

LC Oscillation:

Whenever a charged capacitor with capacity C and an initial charge qo is discharged through an inductor L, the charge and the current oscillate harmonically. And when the resistance of the circuit is zero, there is no energy dissipated in the form of heat. Considering the ideal situation, the total energy associated with the circuit is constant.

The frequency of oscillation is given as,

Or frequency = f = 12𝜋LC

DC Motor:

DC Motor is a machine that converts electrical energy into mechanical energy.

Principle:

The DC motor is based on Faraday’s principle of electromagnetism. It states that whenever a current-carrying conductor experiences a force when placed in a magnetic field and whenever the coil is placed in a magnetic field, it produces torque. And this torque tends to rotate the coil.

Construction:

The Dc Motor consists of two windings, namely field winding and armature winding. The field winding is stationary, whereas the armature winding rotates. The motor also consists of carbon brushes, a laminated armature core, a charge supply, and two poles. The motor also includes a commutator that helps to convert alternating torque into unidirectional torque.

Working of DC Motor:

The force experienced by an arm of the coil is given as,

F = i (l x B)

Suppose a core ABCD is considered, then the force on arm AB will be perpendicular to the plane and point inwards of the coil. But the arm CD will experience a force equal to and opposite to arm AB. If the coil is viewed from the top, the coil seems to turn in a clockwise direction. But due to the commutation, the current in arm AB reverses. The force on arms AB and CD remains in the same direction, and further causes the coil to rotate in the same direction.

Due to the magnetic field, the armature coil rotates, and a back emf is produced. The back emf induced is given as,

e = EiR

This back emf, e, depends on the angular velocity of the armature ⍵ and magnetic field B.

But in the case of the constant magnetic field, back emf is given as,

e ∝ ⍵

e = k⍵

e = NBA⍵sin⍵t

Current in the motor is given as,

i = E – eR = E – k⍵R

When the motor is just switched on, that is e=0. Hence the i = ER will be the maximum,

Hence whenever the motor is just switched on, the current is at maximum value & full high speed. However, it decreases as the motor attains speed further.

The efficiency of DC Motor:

The efficiency of DC Motor is given as

Efficiency η = P mechanicalP supplied = PoutPin = eE = Back e.m.f.Supply voltage

Some important Applications:

DC motors are used in a variety of applications, such as:

• Electric locomotives.
• Electric cars.
• Rolling mills.
• Electric cranes.
• Electric lifts.
• Dc drills.
• Fans.
• Blowers.
• Centrifugal pumps.
• Air compressors.

Working of DC motors is explained in further details in Extramarks Class 12 Physics Chapter 6 Notes. Students can register on Extramarks’ website to get access to our various study materials.

DC Generators:

Generators are machines that convert mechanical energy into electrical energy. A  generator that produces direct current is known as a DC generator.

Construction:

DC Generator is made of the following parts:

• Armature coil.
• Magnet.
• Commutator.
• In DC generators, commutators are used instead of slip rings.
• Carbon brushes.

The commutator helps the coil rotate so that when the direction of ‘e’ reverses in every cycle, the commutator also reverses and makes contact with other brushes. This process makes sure that the current in the external load remains in the same direction.

Working of DC Motor:

The force experienced by an arm of the coil is given as,

F = i (l x B).

Suppose a core ABCD is considered, then the force on arm AB will be perpendicular to the plane and point inwards of the coil. The arm CD will experience a force equal to and opposite arm AB. If the coil is viewed from the top, the coil seems to turn in a clockwise direction. But due to the commutation, the current in arm AB reverses. Since the force on arms AB and CD remains in the same direction and further causes the coil to rotate in the same direction.

Due to the magnetic field, the armature coil rotates, and a back emf is produced. The back emf induced is given as,

e = EiR.

This back emf, e, depends on the angular velocity of the armature ⍵ and magnetic field B.

But in the case of the constant magnetic field, back emf is given as,

e ∝ ⍵

e = k⍵

e = NBA⍵sin⍵t

Current in the motor is given as,

i = E – eR = E – k⍵R

When the motor is just switched on, that is e=0. Hence the i = ER will be the maximum.

Hence whenever the motor is just switched on, the current is at maximum value & full high speed. However, it decreases as the motor attains speed further.

The efficiency of DC Motor:

The efficiency of DC Motor is given as:

Efficiency η = P mechanicalP supplied = PoutPin = eE = Back e.m.f.Supply voltage

Applications of DC Motors:

DC motors are used in a variety of applications, such as:

• Electric locomotives.
• Electric cars.
• Rolling mills.
• Electric cranes.
• Electric lifts.
• Dc drills.
• Fans.
• Blowers.
• Centrifugal pumps.
• Air compressors.

Working Principle of a DC Generator:

Faraday’s laws of electromagnetic InductionInduction govern how a DC generator works. When a conductor is placed in a fluctuating magnetic field (or when a conductor is moved in a magnetic field), an EMF is induced in the conductor, according to Faraday’s Law.

The current will be induced if the conductor is steered with a closed path. The direction of the induced current (determined by Fleming’s right-hand rule) changes as the conductor moves in different directions.

Consider the instance of an armature rotating clockwise and a conductor on the left travelling upward. The direction of travel of the conductor will reverse downward as the armature completes its half rotation. The current will be alternating in direction. A current reversal occurs when the connections of armature conductors are reversed. As a result, the terminals receive unidirectional current.

EMF Equation of a DC Generator:

For a DC generator, the EMF equation is as follows:

Eg = (PØNZ) / 60A

Where Eg = EMF generated in any parallel path.

P  = number of poles in the field as a whole

N  = Armature rotational speed (rpm)

Z  = the Total Number of armature conductors in the field.

Ø  = Magnetic flux produced per pole.

A  = number of parallel paths in the armature.

N/60 =is the number of turns per second

The time for one turn will be dt=60/N sec

Losses in DC Generators:

There are energy losses while converting mechanical energy to electrical energy, as the entire input is not translated into output.

These losses are divided into three categories:

• Copper Loss:

Three copper losses occur as current flows through windings: armature copper loss, field copper winding loss, and brush resistance losses.

• Iron Losses:

Eddy’s current and hysteresis losses arise due to recent InductionInduction in the armature. These losses are also known as Magnetic losses or Core losses.

• Mechanical Losses:

Mechanical losses arise as a result of friction between the generator’s parts.

Types of DC generators:

The DC generator can be Classified into two main categories: excited and self-excited.

• Separately Excited:

An external DC source energises the field coils of a separately excited type generator.

• Self Excited:

The generated current activates the field coils within the generator in a self-excited kind. These generators are divided into three categories: series wounds, shunt wounds, and compound wounds.

Applications of DC Generators:

Applications of DC generators are as follows:

• An independently excited type DC generator uses field regulators for power and lighting.
• Arc lamps use a series DC generator for a reliable, current generator, illuminating, and booster.
• Compounding at a reasonable level, Hostels, offices, and lodges all rely on DC generators for power.
• Compound DC generators are used for supplying power to DC welding machines.
• A DC generator is required to compensate for the voltage loss in the feeders.

Some of the tips and tricks which are elaborated further in our ​​Class 12 Physics Chapter 6 Notes:

• When a bar magnet moves towards a fixed conducting coil, an emf, current, and charge are induced in the coil due to flux variations. The induced emf and induced current increase as the magnet’s speed increases, while the induced charge remains constant.
• induced parameter:

Induced parameter = e₁,i₁,q₁

e₂(>e₁), i₂(>i₁), q₂(=q₁)

• Can electric force lines ever be closed curves? Yes, when a changing magnetic field is involved.
• When  there is no flux cutting and there is no EMI as well.
• Motional emf in vector form: e=(v  X B)
• In motional emf v, B and there are three vectors, if any two vectors are parallel there will be no flux cutting.
• When a metal and a non-metal object are dropped from the same height near the earth’s surface. There is  no induced current in the non-metallic portion, hence it drops with acceleration due to gravityAnd thus,  it will reach the ground first.
• When an aeroplane lands or takes off with its wings in an east-west direction, the potential difference or emf is induced across the wings. However,  there will be no potential difference or emf if an aeroplane is landing or taking off with its wings in the north-south orientation.
• As the earth’s magnetic field has no vertical component, no emf is generated when a conducting rod moves horizontally on the equator. However, BV is highest at poles, resulting in maximal flux cutting and emf induction.
• When a conducting rod falls freely in the earth’s magnetic field with its length running East-West, the induced emf grows with time and the induced current flows from west to east.
• Henry y=109emu. y=109emu of inductance or 109ab 109ab – henry.
• A solenoid’s inductance at the ends is half that of the inductance in the middle.

(Lend =½ Leconte)

• The resistance is primarily a thin, long wire made of a high-resistivity substance. However, it does have some inductance and capacitance. As a result, getting a pure resistor might be difficult. Capacitors and inductors that are pure are also hard to come by.
• Due to the inherent presence of self-inductance in all electrical circuits, even a resistive circuit with no capacitive or inductive elements retains any inductance.

By folding back the coil on itself, as in the coils of a resistance box, self-inductance can be decreased.

• Mutual inductance is impossible without self-inductance, whereas self-inductance may or may not be achievable without mutual inductance.
• If the coil’s central current increases, (i↑) so didt will be positive (+ve), hence induced emf e will be negative (i.e. opposite GMF)=Enet= E- e
• When the key is rapidly opened, a high momentarily induced emf is occasionally produced due to the circuit’s high inductance, resulting in sparking at the vital location. To prevent sparking, a capacitor is placed across the key.
• Inductance cannot exist without resistance, but resistance can exist without inductance.
• An inductor’s circuit behaviour differs significantly from that of a resistor. While a resistor opposes the current I, an inductor opposes the change done in the circuit.
• The dc motor is a versatile energy conversion device with a wide range of uses. It can handle loads that require a lot of starting torque as well as torque for acceleration and deceleration.

When a source of emf is connected across the two ends of the primary winding or the two ends of the secondary winding alone, Ohm’s Law can be used. The primary and secondary windings are not electrically linked. Hence ohm’s Law should not be applied to the entire transformer.

• The transformer draws a no-load primary current to supply no-load Cu and iron losses

even with the secondary circuit open.

• The transformer has the best possible efficiency out of all the electrical machinery.

### Class 12 Physics Chapter 6 Notes: Exercises & Answer Solutions

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• Class 12 Physics Chapter 6 Notes: Exercise 6.1 Solutions
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• Class 12 Physics Chapter 6 Notes: Exercise 6.10.1 Solutions
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### NCERT Exemplar Class 12 Physics

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### Key Features of Class 12 Physics Chapter 6 Notes

For scoring good marks in exams and gaining a better understanding of the subject, thorough preparation is required. With so many study materials available on the internet, it becomes troublesome for students to choose an the right website for appropriate guidance. Thus, Extramarks is here with the best in  class faculties who create well-researched study materials. Here are few more benefits of using study material provided by Extramarks.

• The study notes prepared by subject experts at Extramarks are an excellent walk-through of all CBSE concepts covered in respective chapters of all the subjects.
• The experts at Extramarks follow all guidelines laid by CBSE to draft solutions which are beneficial for the students.
• All the notes are prepared in simple and easy to understand language. The solutions and  revision  notes are explained in-depth which helps the students to form strong conceptual base for further courses. .

These serve as guide in helping the students to crack competitive tests  like NEET, JEE Main, Advanced.

### 1. Is there any alternative to Class 12 Physics Chapter 6 Notes?

There is a lot of study material available on the internet. However, choosing the right Notes and solutions will help you understand the topic better and learn the method of writing answers for examinations. We highly recommend all the students refer to Class 12 Physics Chapter 6 Notes prepared by the expert team at Extramarks.

### 2. Is it easy to study Class 12 Physics Chapter 6 Notes?

Class 12 Physics Chapter 6 is an easy and informative topic. If appropriately studied, students can score good marks in examinations. But before approaching any other study material, read thoroughly from NCERT textbooks and then further learn from Class 12 Physics Chapter 6 Notes and NCERT Solutions Class 12 Physics Chapter 6. This will help you better understand the topic and perform well in examinations.

### 3. What is Motional Electromotive Force?

1. As explained in Extramarks Class 12 Physics Chapter 6 Notes a motional electromotive force is an EMF generated by the movement of the conductor (a rectangular coil) towards the magnetic field ‘B.’ Its formula is as follows:

E = – vLB

As long as the velocity (v), field (B), and length (L) are all perpendicular to each other, this equation holds. The minus symbol deNotes Lenz’s Law.

### 4. Write Applications of Electromagnetic Induction.

1. The following gadgets work based on the EMI phenomenon:
• Generators of Electricity
• Dynamos
• Transformers

### 5. How can I Score Well in the Class 12 Physics Examination?

1. Physics 12 necessitates a lot of practice. It is vital to follow the suggestions listed below to have a good grasp of concepts.
• Along with NCERT Textbooks students should register on Extramarks platform to get access to various Physics related study materials such as Class 12 Physics Chapter 6 Notes.
• Examine the most recent CBSE Syllabus.
• Stick to your study schedule and organise your topics in a hierarchical order.
• Review the themes daily.
• Solve practise papers to improve your numerical problem-solving skills (available on Extramarks with solutions).
• Choose solved Past Year Question Papers to stay up to speed on the difficulty of the questions and the importance of each topic.

### 6. What is the Weightage of Numerical Type Questions in the Class 12 Physics Examination?

1. The numerical type questions in any Class 12 Physics test unit have no special wightage . Numerical type questions from some sections have a weightage of 10-15 marks.

Students can refer to Extramarks Class 12 Physics Chapter 6 Notes to get more information about important questions, chapter weightage and other exam related information.

### 7. What are the essential topics for Class 12 Physics apart from Chapter 6?

You must consider what topics you should concentrate on as your final examinations approach. You should be aware that each chapter is critical. Nevertheless, each chapter contains a few key concepts. Few of the most important topics that are covered are Coulomb’s Law, electric dipole potential, Ohm’s Law, the magnetic force on the current-carrying wire, the axial magnetic field of a bar magnet on the solenoid, magnetic Flux, RC, LC, LR, and LCR circuits, displacement current, picture generation, etc.

### 8. How to score more than 90% in Class 12th CBSE in Chapter 6?

NCERT textbooks and their concepts are commonly used in board  examination papers. As a result, learning from NCERT textbooks and Extramarks’ solutions can help you pass your  board  examinations with high scores. You might be required to read other reference books in addition to NCERT textbooks. Apart from the problems in the book, you must solve the questions from all past years’ question papers to achieve a score of more than 90% in the CBSE Class 12 Boards examinations.

### 9. What is Faraday's First Law?

1. The fundamental Law of Induction is Faraday’s First Law of electromagnetic Induction in Physics. When fluctuating magnetic fields are induced in closed coils, this Law indicates that electric currents can be generated. As long as the magnetic flux varies frequently, these induced electric magnetic fields can survive for an extended period. As a result, the chemical change caused by the current in the electrode-electrolyte is stated to be proportionate to the overall quality of electricity employed. Refer to the revision notes on Extramarks for a complete explanation.

Refer to Extramarks’ Physics study resources such as Class 12 Physics Chapter 6 Notes to clear concepts related to Physics subject.