# Xam Idea Class 12 Physics Chapter 6 Solutions: Electromagnetic Induction

Xam Idea Class 12 Physics Solutions Chapter 6 ‘Electromagnetic Induction’ is based on the concepts of electromagnetic induction. You will uncover major topics, laws, and formulae around this important topic of Physics. The questions in this chapter are specially designed for CBSE Class 12 board exams while you also get to know what comes in competitive engineering and medical exams. The key topics discussed in these solutions are Faraday’s law of electromagnetism, magnetic flux, self, and mutual induction, Lenz’s law, electromotive force, and formula around it, Eddy currents and its applications, induce EMFs.

Xam Idea Class 12 Physics Solutions Chapter 6 ‘Electromagnetic Induction’ has a total of 106 questions divided into 8 sections. The questions are varied with some short and long answer types, objective types, and some HOTS (high order thinking skills) problems. There is extensive coverage of all key topics and you will get enough exposure to every kind of question that can come on electromagnetic induction.

Our team of subject matter experts strives to provide Xam Idea solutions to all the problems clearly and concisely. This will help you understand the concepts and clarify all your doubts. The intensive research done by our teachers will show you how to approach a complicated problem by breaking it down into simpler ones. This will enable you to tackle any kind of question and also help you in memorizing formulas quickly.

## Important Topics for Xam Idea Class 12 Physics Solutions Chapter 6: Electromagnetic Induction

**Electricity and magnetism –**A moving electric charge creates a Magnetic field and its converse is also true, i.e. a magnetic field induces motion in electric charge thereby producing an electric current.**Magnetic flux –**The magnetic flux through any surface is measured by the number of magnetic field lines that are crossing that surface and are perpendicular to it.

ϕ = M.A Cos θ

Here M – magnetic field

A – Area of the surface

θ – the angle between the magnetic field and the area vector

Magnetic flux is measured in weber and it is a scalar quantity.

**Electromagnetic Induction**– The induced EMF (electromagnetic force) and induced current in a closed circuit due to change in magnetic field lines is called electromagnetic induction.**Faraday’s law of Electromagnetism:**Using these fundamentals, Faraday and Henry did a series of experiments which gave way to 2 laws of electromagnetic induction came out:**First law**– If there is a change in the magnetic field inside a conductor, an electromotive force is induced and in a closed circuit conductor, a current is induced.**Second law – Quantification of EMF**– The rate at which magnetic flux changes with time within the circuit determines the magnitude of EMF induced in the circuit:

ε = N (d*ϕ*/d*t*)

Here ε – Electromotive force

*Φ* – Magnetic flux

* *t – Time

N – Number of turns in the closed coil

**Lenz’s Law and Conservation of Energy –**This law states that the current induced in a closed conductor with a magnetic field inside always tends to oppose the cause of this induced current. So when you push the N-pole of a bar magnet towards a coil it induces a current in the coil, this current repulses the bar magnet and extra work is required to keep moving the bar magnet towards the coil. This extra work is converted into electrical energy and dissipated as heat.

ε = ‒ N (d*ϕ*/d*t*)

The negative sign shows that the current induced flows in the opposite direction of the cause of the current

**Mutual Induction:**When 2 coils are placed close to each other and the current in one coil is changed (primary coil) it changes the magnetic flux linked with the other coil (secondary coil) resulting in an EMF in the secondary coil. This is called mutual induction and expressed as:

Φ_{2} = MI_{1}

It is measured in Henry.

**EMF in moving conducting rods –**If a conducting rod of length l moves with velocity v in a magnetic field of induction M in a way that v, l, M and perpendicular to each other, then the produced EMF is given by:

E = -vLM

Here M – magnetic field

L – Length of the conductor

v – Velocity with which the conductor is moving

**Eddy Currents –**Eddy currents are generated when a thick conducting rod is placed in a varying magnetic field. The field induces a current in the conductor which in turn heats up the conductor and the free electrons traverse closed paths due to Lorentz force, forming small current loops. These are called eddy currents. Since such currents produce heat losses they have applications in induction heating, welding, etc.

P = C_{e}f^{2}M_{x}^{2}t^{2}

Here P – Path of the eddy current

Ce – A constant which is dependant on the size of the material and inversely proportional to its resistivity

f – frequency of the source of excitation

Mx – the highest value of the magnetic field

t – thickness of the material

#### Discussion of Exercises of Xam Idea Class 12 Physics Solutions Chapter 6: Electromagnetic Induction

- The first exercise has 12 selected NCERT questions where you test your knowledge of calculating EMF in rings, EMF in moving conductor, mutual inductance, calculating current and power loss.
- The 2
^{nd}set has 20 questions which are objective types. It covers the basics of electromagnetic induction like magnetic flux, Lenz’s law, mutual inductance. - The 3
^{rd}set has 1 question which is assertion-reason type. There are 10 statements that have a combination of an event and its cause; you need to choose the right combination. - In the 4
^{th}set, you need to give very short answers for its 24 questions. Questions are based on calculating EMF, give reasons or explanations of some statements, identify the law of polarity of EMF. - The 5
^{th}set has 15 questions that need short answers. Questions are on the magnetic field in a circular loop, induced EMF in moving rod, mutual inductance, Eddy currents. - The 6
^{th}set has 14 questions of long answer type. There are questions on mutual inductance, application of magnetic flux formula, self-inductance, induced EMF. - The 7
^{th}set is again a long answer type with 7 questions. Questions are on the concept of induced EMF, the polarity of EMF, self-inductance, mutual inductance, Lenz’s law. - In the 8
^{th}set, there are 13 questions where you can self assess your knowledge on the topics discussed in this chapter. Almost all the key topics are present in this section.

## Why Use Xam Idea Solutions for Class 12 Physics Chapter 6: Electromagnetic Induction by Instasolv?

- Xam Idea Solutions Physics can be a tricky topic for Class 12 as it has many advanced concepts to understand.
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