# CBSE Class 12 Physics Revision Notes Chapter 6

## Introduction to Class 12 Physics

Class 12 Physics includes various advanced Chapters related to different concepts and principles. Physics subject is considered to be one of the most interesting but tricky subjects. It is filled with numerous engaging concepts and problems. The concepts taught in Class 12 are the fundamentals of the subject. Students are advised to focus and learn these concepts in-depth to develop their skills and build a strong foundation. This subject is essential if a student is planning to pursue engineering, scientific research, and other similar fields.

### Class 12 Physics Chapter 8 notes

The Chapter 8 physics Class 12 notes are based on electromagnetic waves. The properties of the various electromagnetic waves such as the Radio waves, Microwaves, Infrared waves, Lightwaves, Ultraviolet waves, X-rays and Gamma rays will be described in detail in this Chapter. The students will also learn how these waves are produced, detected and behave in different conditions. With the help of Class 12 physics Chapter 8 notes, students will gain an understanding of the other laws and equations that electromagnetic waves follow. The  CBSE revision notes include coloured pictorials and graphical representations to make this Chapter more interesting and engaging.

Students will find learning the concepts related to sources, nature and energy of electromagnetic waves easier with the help of these Class 12 Physics Chapter 8 notes. It includes several equations based on which students will have to solve the numerical problems.

Let us glance through all the key topics that the CBSE Class 12 Physics Chapter 8 notes cover. Students are advised to use these revision notes to understand each concept and get access to various important and most-likely problems for extensive practice. With Extramarks, plan your journey towards excellence!

### NCERT Class 12 Physics Chapter 8 Notes: Key Topics

The Class 12 Physics Chapter 8 Notes explain the following topics in detail:

• Introduction
• Displacement current
• Electromagnetic waves
• Sources of electromagnetic waves
• Nature of electromagnetic waves
• Electromagnetic spectrum
• Different types of electromagnetic waves

### Introduction

This Class 12 Physics Chapter 8 Notes discuss the need for current displacement and its consequences. Then, a description of electromagnetic waves is included. The electromagnetic spectrum, stretching from rays to radio waves, is described in detail. In Chapter  8, Physics Class 12 notes, how the EM waves travel for communication is discussed. Maxwell’s equations formulate a set of equations involving electric and magnetic fields, charge and current densities. Along with the Lorentz force formula, the Class 12 Physics Chapter 8 Notes expresses all the fundamental laws of electromagnetism.

• Some of the essential applications of electromagnetic waves are as follows:
• We can see everything around us because of EM waves.
• These waves help in aircraft navigation and to evaluate the speed of aeroplanes.
• These waves have important applications in the medical field, too, such as laser eye surgery.
• Electromagnetic waves are used to transmit broadcasting signals on the radio and television.
• These waves help in determining the speed of moving vehicles.

Maxwell’s Experiments

Maxwell proposed that a time-varying electric field generates a magnetic field. This magnetic field generates an electric field.

According to Faraday Lenz’s law, an EMF is induced in the circuit when there is a change in the magnetic flux in a circuit.

Therefore, the electric current is generated in the circuit. This induces an electric field.

According to Maxwell, a time-varying electric field will also be able to induce a magnetic field.

Maxwell considered three different amperial loops and tried to calculate the magnetic field of the capacitor. Ampere’s circuital law should be the same for all three setups.

Class 12 Physics Chapter 8 notes provide ample exercises and cases that students may refer to such  cases as  given below.

Case 1: Consider a surface of radius r. Let dl be the circumference of the surface. Then using the Ampere’s circuital law, we get

B.dl=oI or

B (2r) = oI

Therefore, the value of B = oI2r

Case 2: Consider a surface(box) with an open lid and apply the Ampere’s circuital law

B.dl=oI

Since there is no current flowing, therefore I = 0

Or B.dl = 0

Case 3: Consider the surface between 2 plates of the capacitor; in this case, also I= 0, so B= 0

• The value of the magnetic field is different at the same point, having different amperial surfaces. They are not the same for the same point.
• Maxwell suggested that there are some spaces or  gaps in Ampere’s circuital law.
• He corrected Ampere’s circuital law and made it consistent in all the scenarios.

The Class 12 Physics Chapter 8 Notes have explained Maxwell’s experiments in an easy and lucid manner. Students can refer to the unlimited problems given in the notes.

Displacement current

Under this section of Class 12 Physics Chapter 8 notes, students will learn about displacement current. For logical consistency, Maxwell showed that a changing electric field must produce a magnetic field. This is important because it explains the existence of forms of electromagnetic waves such as radio waves, gamma-rays and visible light. Consider a charged capacitor. By applying Ampere’s circuital law, we can find a magnetic field at any point outside the capacitor.

It is given by B.dl=oi(t)

There is a conduction current Ic in the plates outside the capacitor. There is Displacement current Id in the area between the plates. The behaviour of the displacement current is equal to that of the induction current.

For static electric fields, the displacement current is zero, Id= 0, and for time-varying electric fields, Id ≠ 0.

As mentioned in Class 12 Physics Chapter 8 notes, for a circular loop, the magnetic field is directed along its circumference. It is the same in magnitude at all points in the loop. Let the magnitude of the field be B, then the above equation becomes,

B (2πr) = oi(t)

Consider a pot-like surface having the same boundary. On this surface, it touches the current, but its bottom is between the plates of a capacitor, and its mouth is a circular loop.

On applying the Ampere’s circuital law to surfaces having the same perimeter, we find that B (2πr) = 0 since there is no current passing through the surface.

Suppose the capacitor plates have area A and charge Q, the magnitude of electric field E between plates QAo. The field is perpendicular to the surface. It has the same magnitude over area A of the plates of the capacitor and vanishes outside it. Using Gauss’s law, it is

E=EA=QA. o. A = Qo

Now, if the charge (Q) on the plates of a capacitor changes with time, then the current i = (dQdt). We have

dEdt=ddt(Qo)=1odQdt. This implies o(dEdt) = i. This is known to be Ampere’s circuital law.

Furthermore, as mentioned in Class 12 Physics Chapter 8 notes, to generalise this law we add to the total current carried by conductors and o times the rate of change of electric flux, which is equal to the current I for all surfaces.

For the generalised Ampere’s law, the magnetic field B at point P is non-zero for all surfaces. B outside at a point P is equal at a point M inside the plates. This current which is carried by the conductors because of the flow of charges, is known as the conduction current. The current is due to changing electric fields. It is also called Maxwell’s displacement current.

The generalisation made by Maxwell is that the source of a magnetic field is the conduction of electric current because of the flowing charges and the rate of change of the electric field with respect to time. We can say that the total current (i) is the sum of the conduction current (Ic) and displacement current (Id), which is equal to Ic+ o(dEdt).

This means that outside the capacitor plates, there is only conduction current (Ic)= I, and displacement current is absent, i.e., Id= 0.

Whereas, inside the capacitor, the conduction current is absent, i.e., Ic= 0, and there is only displacement current, Id = i.

The generalised Ampere’s circuital law as mentioned in Class 12 Physics Chapter 8 notes has the same form except that ‘the total current passing through any surface with a closed-loop is the perimeter is the sum of the conduction current and the displacement current’. It is known as the Ampere-Maxwell law and is given as B.dl=oIc+oodEdt.

The displacement current and the conduction current have the same physical effects. For example, the displacement current in the steady electric fields in a conducting wire may be zero as the electric field E is independent of time. Also, in the charging capacitor, the conduction, as well as the displacement currents, may be present in different regions of space. In most cases, they both may be present in the same spatial region, as a perfectly conducting or perfectly insulating medium does not exist.

As per Class 12 Physics Chapter 8 notes, Faraday’s law of induction claims that the induced EMF is equal to the time rate of change of magnetic flux. The EMF between two points is said to be the work done per unit charge in travelling from points 1 to 2. Therefore, the existence of an EMF signifies the presence of an electric field. In other words we can say that a magnetic field which changes with time will give rise to an electric field and then an electric field which changes with time will give rise to a magnetic field. It is basically the symmetrical counterpart, and a consequence of the displacement current is a source of a magnetic field. Thus, electric and magnetic fields with respect to time give rise to each other!

Using Faraday’s law and Ampere-Maxwell’s law of electromagnetic induction, we can get a quantitative expression of this statement.

Electromagnetic waves

Under this section of Class 12 Physics Chapter 8 notes, students learn about electromagnetic waves. Electromagnetic (EM) waves are related to electricity and magnetism and are coupled with time-dependent electric and magnetic fields which propagate in space. They emerge from Maxwell’s equations. He found the special properties of Electromagnetic waves, which are useful for many practical purposes.

Therefore, we can say that (electric field + magnetic field) with respect to time is equal to the Electromagnetic waves. The electric waves vary in the form of sinusoidal waves. The magnetic wave is a sine wave in the direction perpendicular to the electric field.

Source of Electromagnetic waves:

The EM waves are generated when the electrically charged particles oscillate. They are also termed accelerating charges. The electric field analogous to the accelerating charge vibrates to generate a vibrating magnetic field. Both the vibrating electric and magnetic fields give rise to electromagnetic waves.

If the charge is at rest, then the electric field analogues to the charge will be static. Therefore, EM waves will not be generated as the electric field is independent of time. Whereas, when the charge moves with uniform velocity, then the acceleration is zero. The electric field constantly changes with time. As a result, no electromagnetic waves will be generated. This means that only the accelerated charges have the ability to generate the EM waves. The frequency of the EM wave is equal to the frequency of oscillation of the charge.

Nature of electromagnetic waves:

In this section of Class 12 Physics Chapter 8 notes, students will get a brief introduction to the nature of electromagnetic waves.

The electromagnetic waves are transverse waves, i.e., the direction of disturbance or displacement of the wave in the medium is perpendicular to the direction of propagation of the wave. The particles of the medium will also move in the direction perpendicular to the direction in which the wave is propagating.

For EM waves, consider that the propagation of the wave takes place along the x-axis, then the electric and magnetic fields will propagate on the y-axis and z-axis, respectively, i.e., perpendicular to the wave propagation.

Hence the EM waves are transverse in nature. The electric field of the EM wave is given as

Ey = Eo sin(kx–ωt), where Ey is the electric field along the direction of propagation of waves.

The number k is (2) and the magnetic field is represented as Bz= Bo sin(kx-ωt), where Bz is the electric field propagating along the z-axis and x=direction of the wave. The EM waves propagate along the z-direction (a function of the z-coordinate) with respect to time t.

The values for Ex and By is given as: Ex = Eo sin(kx–ωt) and By = Bo sin(kx–ωt), where k = 2 shows the relations between k and , ω is the angular frequency. The value of k is known to be the magnitude of the wave vector and its direction depicts the direction of the propagation of the wave. The speed  is given by k.

Using Ex, Byand Maxwell’s equations, we get = ck, where c =1oo. The relation ω = ck is often written in terms of frequency and wavelength.

Maxwell’s equations state that the magnitude of the electric and magnetic fields in an EM wave are related as Bo=Eoc.

Some features of electromagnetic waves as mentioned in Class 12 Physics Chapter 8 notes are:

• They are self-sustaining oscillations of the electric and magnetic fields in vacuum or free space.
• They differ from all the other waves as there is no medium  involved in the vibrations of the electric and magnetic fields.
• Sound waves are longitudinal in the air of compression and rarefaction, whereas the Transverse waves on the surface of water spread horizontally and radially inwards.
• Transverse waves can propagate in a rigid solid that resists shear.

In the nineteenth century, scientists thought that there must be some medium pervading space and matter, which respond to both electric and magnetic fields. They named this medium Ether. However, we now accept that no such medium is needed.

The energy of Electromagnetic waves:

As the Electromagnetic waves propagate, they carry energy. Due to this energy, the EM waves have a wide range of practical uses in our day-to-day life. Energy is partly carried by an electric field and partly by the magnetic field.

Mathematically,

The total energy stored per unit volume in an EM wave, represented by (Et), is equal to the sum of energy stored per unit volume by an electric field and magnetic field individually.

Therefore, (Et) = Energy per unit volume stored by the electric field + Energy per unit volume stored by the magnetic field.

Et = E202 + B220

Experimentally, we know that the speed of the EM wave is equal to the speed of the light c = (EB)

This implies, B = (EC)

Therefore, Et = E202 + E22c20. But, c =1oo from Maxwell’s equation.

So, Et = E202 + E2oo20 or Et = E202 + E2o2, which implies

Et = E20 is the total amount of energy stored per unit volume in the electromagnetic wave.

Students are advised to study and learn with the help of the Class 12 Physics Chapter 8 Notes to understand the energy induced by the Electromagnetic wave concept clearly.

Properties of EM waves:

1. The velocity of the EM waves in a vacuum (free space) is a constant and is equal to the speed of light. Therefore, c = 3 x 108m/s) is a constant and c=(1oo).
1. No material medium is necessary for the propagation of EM waves. However, they can propagate in a medium also in the presence of electric and magnetic fields. Within a medium, the velocity v = (1), where =permeability and =permittivity of a given medium.
1. EM waves carry energy as well as momentum. The total amount of energy stored per unit volume in EM wave is given as Et = E20. The momentum of EM waves is given as p = Uc. EM waves are used for important practical purposes such as communication on mobile phones, telecommunication on radio, and more.
1. The EM waves exert pressure. As they propagate with energy and momentum, they exert pressure. It is termed radiation pressure.

The Classification of electromagnetic waves based on their frequency or wavelength is known as the Electromagnetic spectrum.

According to the wavelength, the EM waves are Classified into different categories. However, it is important to note that there  is no sharp division between two different waves.

The different categories of the electromagnetic waves in decreasing order of their wavelength are given below:-

Microwaves: 0.1 m – 1 mm

Infra-red waves: 1 mm – 700 nm

Visible light waves: 700 nm – 400 nm

Ultraviolet waves: 400 nm – 1 nm

X-rays: 1 nm – 10-3 nm

Gamma rays: < 10-3 nm

These waves together constitute the EM spectrum.

Tip:- In order to remember the order of the wavelength of each wave, just write the initial letter of all the waves in decreasing order.

So, it becomes R, M, I, V, U, X, G.

Hint: Red Man In Violet Uniform X Gun.

EM Energy of waves in the Electromagnetic Spectrum

The EM waves are described by their energy, frequency or wavelength.

1. Frequency:
• The microwaves and radio waves are described using frequencies.
• Frequency is defined as the number of crests which can pass through a given point in one second.
• If a wave having three crests passes through a point in 1 second. Then we can say that the frequency of that wave is 3Hz.
1. Wavelength:
• The Infrared waves and visible waves are described in terms of wavelength.
• The wavelength of a wave is defined as the distance between any two consecutive crests or troughs.
• Wavelength might vary from small value to large value.
• SI unit is metre.
1. Energy:
• The X-rays and Gamma rays are generally described using energies.
• An EM wave is described in terms of energy in the units of eV.
• eV is defined as the amount of kinetic energy required to move 1 electron through a potential of 1 volt.
• As the wavelength decreases, moving along the EM spectrum, energy increases

The Class 12 Physics Chapter 8 Notes include a detailed explanation to help students in their exam preparations.

Relation between Wavelength (λ) and Frequency (ν)

C = . λ, where λ is the Wavelength and is the Frequency of an EM wave.

Therefore, we can say that λ = (c)

Now, we know that E= h = h c

Energy is proportional to frequency and inversely proportional to the Wavelength, i.e., E ∝ and E ∝ (1)

Therefore from the EM spectrum,

Decreasing order of wavelength R, M, I, V, U, X and G

Increasing order of frequency G, X, U, V, I, M and R

The Radio waves are produced by the accelerating motion of charges in the conducting wires.

An essential application of radio waves is in-

• Radio and television communication systems.
• Mobile phones for voice communication.

In the EM spectrum, the wavelength (λ) of radio waves is > 0.1 m.

The Radio waves are further Classified into different bands:-

• Amplitude Modulated (AM) band similar to FM channels: 530 kHz to 1710 kHz. These are known to be the lowest frequency band.
• Short wave band: up to 54MHz
• TV waves band: 54MHz to 890MHz
• Frequency Modulated (FM) band: 88MHz to 108MHz
• UHF band- Ultra high-frequency

Microwaves

The Microwaves are known as short-wavelength radio waves. They are produced using special vacuum tubes such as klystrons, magnetrons or Gunn diodes. Furthermore, they are generally used in microwave ovens and for radar systems in aircraft navigation.

There is a wide range of RADAR applications. Some of these include

1. Air traffic control:
• To manage air traffic, the RADAR technology is used. The pilot will get an idea if any other aeroplane is there nearby or not.
• The pilot will also know about the climatic conditions during the take-off and landing of the aeroplane.
• It also helps in aircraft navigation.
1. Speed detection:

The instruments used to detect the speed of the moving vehicles on the roads use radar technology.

1. Military purposes

It helps to detect enemies and weapons.

1. Satellite tracking

To track satellites, RADAR technology is used.

The Class 12 Physics Chapter 8 notes include detailed and well-explained information about the RADAR technology and microwaves.

• They use short-wavelength waves, which are the same as microwaves.
• They are invisible to humans.
• Even the slightest presence of microwaves is easy to detect.

It comprises a transmitter and a receiver.

1. Transmitter: It transmits the microwaves.
2. Receiver: It receives the echo produced when the microwaves strike any object. When the receiver receives the reflected ray, it can also track the presence of another object in the vicinity.

Microwave ovens:

• They have a smaller wavelength.
• The waves can get absorbed by water, fats and sugar.

Working of the microwave oven:

• The microwave oven is used to heat anything uniformly.
• The food material will have water, sugar and fats present in it.
• When we heat any food inside the microwave oven, the microwaves penetrate inside the food.
• So these waves get absorbed by the water and the fat molecules present in the food.
• The molecules of the food material start moving randomly with some frequency.
• Therefore the frequency of the microwave will be equal to the frequency of the molecules.
• As these molecules are in random motion, the temperature increases and food gets heated uniformly.
• There are two ways to heat an object:-
1. Conduction of heat: It happens when anything is heated over a gas burner.
2. Exciting the molecules: This technique is used in the microwave oven.

NOTE:

It is essential to use the porcelain vessels and not metal containers in a microwave oven as there is the danger of getting a shock from the electric charges. There are also chances the metals might melt from heating. The porcelain container is a bad conductor of heat. They remain unaffected and cool as they cannot absorb microwaves because the large molecules vibrate and rotate with smaller frequencies. Hence, they do not get heated up.

Infrared waves

• Infrared waves, also known as heat waves, are produced by hot bodies.
• Their wavelength is less than that of both radio waves and microwaves.
• They  are easily  absorbed by water.

Some Applications of Infrared waves are as follows:

The Infrared waves are used in Infrared lamps, Infrared detectors, and LED in remote switches of electronic devices such as video recorders and hi-fi systems. The Greenhouse effect is also an important application of the Infrared waves.

Some examples are

1. Fire gives both visible light waves, which are visible to us and infrared waves, which cannot be seen with naked eyes.
2. Humans also generate some amount of infrared waves.
3. With the help of some special glasses having infrared detectors, we can view the infrared waves.
4. Infrared lamps are usually used to heat the food materials and sometimes in washrooms.
5. There is an LED present both on the TV and on the remote that helps us to switch on the television using a remote controller. The infrared waves are used to transfer this signal.

The Greenhouse Effect:

The greenhouse effect is the atmospheric heating phenomenon. This allows the solar radiation to pass but blocks the heat radiated back from the surface of the Earth.

Let the sun give radiation to the Earth in the form of visible light. When this visible light reaches the surface of the Earth, all the objects present on the planet receive heat and become hot. The visible light carries energy from the sun and transfers it to all the objects. The hot object will now transmit infrared waves, and the Earth will reradiate the infrared waves. When these waves travel in the atmosphere, they get trapped by greenhouse gasses such as CO2, CH4 and water vapour. We can say that heat is trapped inside the Earth, which increases the temperature.

Therefore, this greenhouse effect makes the Earth warm. Global warming also takes place due to the increase in pollution and temperature of the environment.

Visible or Light rays

• Visible or Light waves are the most common form of Electromagnetic waves.
• Their wavelength range is 4x1014 Hz to 7x1014
• We are able to see everything around us because of the light rays.
• The radiation received from the sun reaches the earth in the form of visible light.
• Many insects have compound eyes because of which they can see not only the visible light but also the UV rays.
• Snakes are also able to see the infrared rays.

Properties of Light rays:

The following phenomenon takes place due to light rays:

• Reflection
• Refraction
• Interference and diffraction
• Polarisation
• The photoelectric and photographic effects,
• Photographic action and sensation of sight.

Visit the Class 12 Physics Chapter 8 notes to gain more information about Visible or Light rays.

Ultraviolet rays (UV rays)

These rays cover wavelengths ranging from about 4 × 10-7m (400 nm) to 6 × 10-10m (0.6 nm).

• The UV rays are produced by the hot bodies (sun) and some special lamps.
• The UV rays have dangerous effects on human beings.
• UV lamps are generally used to kill germs in water purifiers.

Some examples are:

• When UV rays fall on humans, then it leads to the production of a pigment known as the melamine, which causes tanning of the skin.
• To protect ourselves from UV rays, sunscreen and glasses are used. They absorb this light.
• UV rays also are important in LASER eye surgery.
• The UV rays have a very short wavelength. Therefore, they are focussed on a narrow beam of light.
• The ozone layer present outside the atmosphere protects the earth from UV rays.
• The ozone layer has the ability to reflect the UV rays. However, because of the use of chlorofluorocarbon (CFC), the ozone layer is depleting. If the ozone layer gets depleted, then humans will be exposed to the UV rays coming from the sun.

X-rays

• The X-rays are produced when the metal target is bombarded with high energy electrons.
• It is a very important diagnostic tool.
• These rays have lesser wavelengths than all other waves. Because of this, they can easily penetrate inside the skin of low-density material.
• In a high-density material, it gets reflected or absorbed.
• In an X-Ray, the bones look darker, and the lighter area highlights the skin.
• X-rays are commonly used for the treatment of cancer.
• There is an unwanted growth of the cells in cancer. To treat cancer, this abnormal growth of cells is stopped using X-rays. These rays damage the living tissues.

Gamma Rays

• These rays are produced through nuclear reactions and are emitted by the radioactive nuclei.
• They are also used in cancer treatment.
• Gamma rays have a small wavelength. So they help to kill the growth of unwanted cells in cancer.

The Class 12 Physics Chapter 8 notes summarise different types of EM waves, thor production and detection in the table below.

 Waves Production Detection Radio Rapid acceleration and  decelerations of electrons Receiver’s aerials Microwave Klystron or magnetron valve Point contact diodes Infrared The vibration of atoms & molecules Thermopiles Bolometer, Infrared photographic film Light waves Electrons in an atom emit light when they move from a higher energy level to a lower. The eye  Photocells  Photographic film Ultraviolet Inner shell electrons in the atoms move from one energy level to another Photocells  Photographic film X-rays X-ray tubes or inner shell electrons Photographic film  Geiger tubes  Ionisation chamber Gamma rays Radioactive decay of the nucleus -do-

### Class 12 Physics Chapter 8 notes – Summary

Extramarks aim to address all the doubts and difficult topics  students face while studying this Chapter by providing the Class 12 Physics Chapter 8 notes. It enables students to prepare the Chapter for their examination without any hassle. We offer opportunities for unlimited learning so that students can always do their best and achieve their goals.

Students can gain apt knowledge about electromagnetic waves, their properties and their characteristics. The Class 12 Physics Chapter 8 notes include a simplified explanation of the definition of EM waves, Maxwell’s experiments, and Ampere’s Circuital Law. Every case in this law is illustrated using segregated pointers and proper equations so that students can remember these important points.

Students should make sure that they focus on several terminologies introduced in the laws and experiments of this Chapter.

The Class 12 Physics Chapter 8 notes discuss the behaviour of the EM waves in three axes.

Furthermore, Maxwell’s corrections and rectifications to Ampere’s laws are discussed in detail. The following section defines and summarises the displacement current and conduction current using the Ampere-Maxwell law. In the Class 12 Physics Chapter 8 notes, students will find the effect of electric and magnetic fields on the electromagnetic waves’ wavelength, amplitude, frequency, and other features.

### Class 12 Physics Chapter 8 notes: Exercises &  Solutions.

The Class 12 Physics Chapter 8 notes are very important to gain a deeper knowledge of Electromagnetic waves. The summary, key points, tips and formulas included in the notes helps in preparation for board exams as well as several competitive exams such as JEE, NEET, BITSAT, etc. With the help of the Class 12 Physics Chapter 8 notes, students can gain sufficient practice of many important objectives, MCQs and subjective questions. The CBSE revision notes provide logical solutions to all exercise questions. Each solution is explained in a step by step manner.

The Class 12 Physics Chapter 8 notes strictly adhere to the CBSE curriculum and the latest guidelines issued by the board.

Extramarks provide various academic notes with an aim to strengthen the student’s foundation in Physics. Students can access these notes on the Extramarks web portal and mobile application.

Visit the links mentioned below to access the Extramarks Chapter 8 physics Class 12 notes:

### NCERT Class 12 Physics Chapter 8 notes: Key Features

Extramarks Class 12 Physics Chapter 8 notes: Key Features

• Best way to prepare

The notes of Class 12 Physics Chapter 8 assist students in preparing before the exam. It enables quick revision as it includes all important questions, formulas and concepts. Students may refer to these NCERT solutions to understand the right and easy way to solve the numerical problems from the NCERT books. If the students follow the guidelines, they can confidently answer any question in the exam no matter how difficult it is.

• Elementary method of Explanation

The Class 12 Physics Chapter 8 notes focus on strengthening the fundamental concepts of the Chapter. This is very beneficial for students to gain in-depth knowledge of every concept and thus, attain high scores.

• Authored by  Expert Faculty

The CBSE Class 12 Physics Chapter 8 notes are curated by subject matter experts at Extramarks after extensive research. The team has analysed several CBSE sample papers and CBSE  past year question papers. Hence, one can depend on the genuinity of all the details provided.

• Easily accessible

The Class 12 Physics Chapter 8 notes can be easily accessed through any electronic device such as a mobile, laptop, computer, etc., to all students. These solutions will help students to practise CBSE extra questions and understand solutions at their own pace to make progress in preparing the Chapter.

• Essential For Exams

NCERT books and the Class 12 Physics Chapter 8 notes are considered to be the backbone of CBSE Board Examinations. To score good marks, students are advised to not risk skipping any questions included in the CBSE syllabus.

• Plan a Schedule

Studying with the help of the Class 12 Physics Chapter 8 notes will help students to plan a schedule so that they can  complete all Chapters in Physics. It also provides a detailed methodology and step-wise procedure for every problem. Students will learn how to answer  questions  of any difficulty level  in no time.

## 1. Which topics are included in the Class 12 Physics Chapter 8 notes?

The Class 12 Physics Chapter 8 notes explain concepts such as Maxwell’s Experiments, Ampere’s circuital law and Displacement current. The topic mentioned in this Chapter is very crucial for boards and the national level competitive exams. Students will also gain information about different types of electromagnetic waves, their wavelengths and their properties. Using the step-by-step explanations, students will be able to solve several numerical problems and derivations from the Class 12 Physics Chapter 8 notes.

## 2. Are the study materials important? Which are the best reference books for Physics Class 12?

Along with the Class 12 Physics Chapter 8 notes, it is important for students to develop a habit of using various academic notes and reference books. It helps to gain a deeper knowledge and understanding of the concepts included in the Chapter. Below are some of the best reference books authored by Physics experts for students-

 REFERENCE BOOK AUTHOR Concept of Physics Physics Class 12 Fundamental Physics (Volume 1 and 2) Xam Idea Physics for Class 12 Objective Physics Fundamentals of Physics Chapter-wise Solutions of Physics Class 12  New Simplified Physics for Class 12 (Volume 1 and 2) H. C. Verma S. L. Arora Pradeep  – D. C. Pandey Halliday, Resnick and Walker S. K. Singh Dhanpat Rai

## 3. How can I attain high scores in Class 12 Physics Chapter 8 Electromagnetic Waves?

Students who wish to attain the highest marks in Chapter 8 should thoroughly understand every concept given in the NCERT book. They should refer to quick and easy notes, such as the Class 12 Physics Chapter 8 notes. They should also consider solving the practice tests and mock tests available on the Extramarks web portal to access  sample papers,mock tests, and other self assessment tests  based on their preparation level. The Class 12 Physics Chapter 8 notes are a helping guide so that students can refer to the solutions quickly without wasting too much of their time and be prepared ahead of the exam.