Now,   A = \pi R2 = \pi (12 x 10-2)2 = 1.44 \pi x 10-2 m2 From equation (1), we have, {{\partial {E_y}} \over {\partial x}} = {E_o}\cos \left( {x - ct} \right), {{\partial {B_y}} \over {\partial t}} = - c{B_o}\cos \left( {x - ct} \right), Substituting for {{\partial {E_y}} \over {\partial x}}  and {{\partial {B_z}} \over {\partial t}}  in equation (1), {E_o} = c{B_o}     or     c = {{{E_o}} \over {{B_o}}}, It shows that the velocity of electromagnetic waves is equal to the ratio of amplitudes of electric and magnetic fields. These waves required no medium for its propagation. NCERT Solutions. a magnetic field varying with time gives rise to an electric field varying in space. var day = ("0" + now.getDate()).slice(-2); Class-12CBSE Board - Propagation of electromagnetic waves - LearnNext offers animated video lessons with neatly explained examples, Study Material, FREE NCERT Solutions, Exercises and Tests. The wavelength of light in glass, \lambda = {v \over \nu } = vt Electromagnetic waves are coupled time varying electric and magnetic fields that propagate in space. (iii) The electric and magnetic field variation are in phase. At some point by the curvature of the earth, the line of sight propagation gets blocked. Download NCERT Books, Video Lectures ASK DOUBTS Start Discusssion Free JEE Test Series, Get the most advanced study material and top your exams. Therefore, Maxwell modified Ampere’s circuital law. To study the electromagnetic wave propagation let us study the example of production of X rays. if (i < 10) { MCQs. Suggest two methods by which range of TV transmission can be increased. (b)  The average energy density of magnetic field is, {u_B} = {{{B^2}} \over {2{\mu _o}}} = {{{{\left( {{B_o}/\sqrt 2 } \right)}^2}} \over {2{\mu _o}}} = {{B_o^2} \over {4{\mu _o}}}, (c) {u_E} = {u_B} The transverse waves are those in which direction of disturbance or displacement in the medium is perpendicular to that of the propagation of wave. Here  {\Phi _E}   is electric flux. Electromagnetic Waves. Concept: ... Electromagnetic Waves video tutorial 01:01:41; Advertisement Remove all ads. Physics Important Questions Class 12 are given below. The wave equation for light propagating in x-direction in vacuum may be written as, E = {E_o}\sin \omega \left( {t - x/c} \right), where E is the sinusoidally varying electric field at position x at time t. The constant c is the speed of light in vacuum. \oint {\vec E.d\vec s} = q/{\varepsilon _o}, 3. Velocity of electromagnetic waves is also given by. The charging current is constant and is equal to 0.15 A. Faraday's law of electromagnetic induction states that, \oint {\vec E.d\vec l} = - {{d{\Phi _B}} \over {dt}}    (3). The wavelength(λ) and frequency (v) of the EM waves can be related as: c= v.λ. (iv) EM waves are produced by accelerating charged particle. Notes for Electromagnetic Waves chapter of class 12 physics. Question 1. Here you can get Class 12 Important Questions Physics based on NCERT Text book for Class XII. Faraday's Law of Electromagnetic Induction, \varepsilon = - {{d{\Phi _B}} \over {dt}}  or  \oint {\vec E.d\vec l = - {{d{\Phi _B}} \over {dt}}}, \oint {\vec B.d\vec l} = {\mu _o}\left( {{I_C} + {\varepsilon _o}{{d{\Phi _E}} \over {dt}}} \right). This symmetry in the law of electricity and magnetism leads to the conclusion that a time varying electric field gives rise to a time varying magnetic field and vice versa. (b)  What is the wavelength in glass, if refractive index of glass is 1.5? Jan 06, 2021 - EM Waves Properties and Propagation Class 12 Notes | EduRev is made by best teachers of Class 12. Electromagnetic waves are transverse waves. The whole spectrum of electromagnetic spectrum and the modern terminology used for various sections of the spectrum are shown in table. If the incident wave is totally reflected from the surface, the momentum delivered to the surface = U/c - \left( { - U/c} \right) = 2U/c. At any instant, the electric and magnetic fields varying sinusoidally with x can be expressed by equation The four basic laws of electricity and magnetism i.e. The wave while travelling in another path is reflected from a surface at 1 9 km away and further travels 1 2 km to reach the same receiver. It is given by 2. Electromagnetic Waves. The electromagnetic waves produced: (a) will have frequency of 109 Hz. Example 1 (c) at rest. Velocity of light, c = 3 x 108 m/s Therefore,  {{dq} \over {dt}} = C{{dV} \over {dt}}   or   I = C{{dV} \over {dt}} Class 10 Class 12. i.e. It is given by 2. When an electromagnetic wave advances, the electromagnetic energy flows in the direction of \vec E \times \vec B. Electromagnetic Wave Equation. var todaystime = h + ":" + m + ":" + s Here, wavelength \lambda = 5.5 x 10-5 cm = 5.5 x 10-7 m Gauss's law in electrostatics, Gauss's law in magnetism, Faraday's law of electromagnetic induction and Maxwell-Ampere's circuital law are called Maxwell's equations. 673 Views. {E_y} = {E_o}\sin \left( {x - ct} \right)              (1) There is also a sinusoidally varying magnetic field associated with electric field when light propagates. Zigya App. CBSE Class 12 Physics Chapter 8 Electromagnetic Waves notes in PDF are available for free download in myCBSEguide mobile app. Each electromagnetic wave has its characteristic properties and features. Example 2 NCERT Solutions for Class 12 Physics Electromagnetic Waves Notes. Velocity of electromagnetic waves is also given by, c = {1 \over {\sqrt {{\mu _o}{\varepsilon _o}} }}. Ozon layer: The upper region of stratosphere is rich in ozone and is called ozone layer. Textbook Solutions. (iii) The electric and magnetic field variation are in phase. An accelerated charge acts as the source of electromagnetic waves. The S. I. unit of S is watt/(metre)2. There is also a sinusoidally varying magnetic field associated with electric field when light propagates. Gujarat Board Textbook Solutions Class 12 Physics Chapter 8 Electromagnetic Waves GSEB Class 12 Physics Electromagnetic Waves Text Book Questions and Answers. 0.15 A. It is given as: \(\vec{E}\times \vec{B}\). It also bends around the corner of the objects on the earth, Due to this, the energy of the ground wave is gradually absorbed by the earth and the power of the ground wave decreases, The power of the ground wave decreases with the increase in the distance from the transmitting station. The signal wave glides over the surface of the earth, While propagating on the surface of the earth, the ground wave induces current in the ground. CBSE Notes of Class 12 Physics Electromagnetic Waves Introduction. } What are the directions of electric and magnetic field vectors relative to each other and relative to … Electromagnetic Waves. (b) moving in a circular orbit. Thus I = S It shows that the velocity of electromagnetic waves is equal to the ratio of amplitudes of electric and magnetic fields. Concept: ... Electromagnetic Waves video tutorial 01:01:41; Advertisement Remove all ads. The displacement of electrons is caused by the time varying electric field. When energy of electromagnetic wave is incident on a surface, the flux density is called intensity of wave (denoted by I). Various layers in which the atmosphere has been divided are shown in figure. The total radiant flux emitted at any instant is given by where c = velocity of the wave. Each electromagnetic wave has its characteristic properties and features. They do not require a material medium for their propagation. 0.15 A. (c)  Is Kirchhoff's first rule valid at each plate of the capacitor? We have considered below some of the wave propagation methods in brief. Propagation of Electromagnetic Waves. the wavelength of the wave is In the propagation of an electromagnetic wave, a varying electric field E gives rise to a varying magnetic field and so on. function checkTime(i) { Balbharati Solutions (Maharashtra) ... CBSE Previous Year Question Paper With Solution for Class 12 Arts; The propagation of electromagnetic waves can be shown as. Physics Electromagnetic Waves part 1 (Introduction) CBSE class 12. Class 12 Physics Communication Systems. Electromagnetic Waves undergo interference and diffraction. Chapter 8 Electromagnetic Waves Class 12 th Physics deals with various types of radiations sustaining in the environment. (b) will have frequency of 2 × 109 Hz. This phenomenon of loss of power of the ground wave is called attenuation, The attenuation of ground waves increases very rapidly with the increase in its frequency, Thus, ground wave communication is not suited for high frequency signal wave and for very long range communication, To radiate signals with high efficiency, the antennas should have a size comparable to the wavelength of the signal. ( Electromagnetic Waves ) www.free-education.in is a platform where you can get pdf notes from 6th to 12th class notes, General Knowledge post, Engineering post, Career Guidelines , English Speaking Trick , How to crack interview and lots more. Accelerated charges are responsible to produce electromagnetic waves. If the electromagnetic wave incident on a material surface is completely absorbed, it will deliver energy U and momentum, If the incident wave is totally reflected from the surface, the momentum delivered to the surface, According to Maxwell, the accelerated charged particles produce electromagnetic waves. P = {q^2}{a^2}/(6\pi {\varepsilon _0}{c^3}), where q is the charge on the particle and a is its instantaneous acceleration. It helps us to categorize various waves based on their frequency, wavelength, uses, and origin. Electromagnetic Spectrum is the orderly distribution of electromagnetic radiations according to their wavelength or frequency. (iv) EM waves are produced by accelerating charged particle. This video will make you understand about the Electromagnetic Waves basic concept. Class 10 Class 12. (c) Yes, Kirchhoff's law will be valid at each plate of the capacitor, provided electric current means the sum of the conduction and displacement currents. In radio wave communication between two places. Electromagnetic wave equation describes the propagation of electromagnetic waves in a vacuum or through a medium. The magnetic field is perpendicular to the direction of propagation as well as to the electric field E. It is given by, Maxwell discovered the concept of displacement current. (b) These waves propagate through space with speed of light, i.e., 3 10 8 m/s. Answer . Radiant Flux Density. The average value of pointing vector () over a convenient time interval in the … and   {B_Z} = {B_o}\sin \left( {x - ct} \right)     (2) According to Maxwell, the electromagnetic waves are those waves in which there is a sinusoidal variation of electric and magnetic field vectors are at right angles to each other, and the direction of wave propagation. Suggest two methods by which range of TV transmission can be increased. document.write(''); The constant c is the speed of light in vacuum. a magnetic field varying with time gives rise to an electric field varying in space. = 2 \times {10^8} \times 1.8 \times {10^{ - 15}} = 3.6 \times {10^{ - 7}}m, (a)  The average energy density of electric field is, {u_E} = {1 \over 2}{\varepsilon _o}{E^2} = {1 \over 2}{\varepsilon _o}{\left( {{E_o}/\sqrt 2 } \right)^2} = {1 \over 4}{\varepsilon _o}E_o^2. Displacement current is that which results due to the displacement of electrons. the electromagnetic waves are radiated out by the transmitter antenna at one place which travel through the space and reach the receiving antenna at the other place. var m = now.getMinutes(); (d) Total average energy density, {u_E} + {u_B} = 2{u_E} = 2{u_B} = {1 \over 2}{\varepsilon _o}E_o^2 = {1 \over 2}{{B_o^2} \over {{\mu _o}}}, The energy of electromagnetic wave crossing per unit time per unit area perpendicular to the direction of propagation of wave is called the intensity of electromagnetic wave. What is the maximum distance between them for satisfactory communication in LOS mode? (i)   The direction of variation of electric field E and magnetic field B are perpendicular to each other as well as to the direction of propagation. Figure shows a capacitor made of two circular plates each of radius 12 cm and separated by 5.0 mm. Explain. It is given as: \(\vec{E}\times \vec{B}\). 8.12 The source of electromagnetic waves can be a charge (a) moving with a constant velocity. The direction of propagation of the electromagnetic wave is given by vector cross product of the electric field and magnetic field. The wavelength (λ) and the frequency (v) of electromagnetic wave is related as c = v λ = ω/ It is also called range of communication d. The range of space wave communication can be increased by increasing the heights of the transmitting antenna and receiving antenna. var now = new Date(); Propagation of Electromagnetic Waves. (ii)  Speed of EM wave is 3 x 108 m/s in space, in any other medium it depends on the electric and magnetic properties of the medium and is independent of the amplitude of field variation. EM waves are transverse waves. Propagation of electromagnetic waves. Propagation of electromagnetic waves. return i; Propagation of Electromagnetic Waves. Ionisation occurs due to the absorption of the ultraviolet and other high energy radiation coming from the sun, by the air molecues, The phenomenon of bending of electromagnetic waves in this layer so that they are diverted towards the earth is helpful in skywavepropogation. Maxwell discovered the concept of displacement current. (xii) The existence of electromagnetic waves was confirmed by Hertz experimentally in 1888. The total energy flowing perpendicularly per second per unit area into the surface in free space is called a Poynting vector \vec S, where \vec S = {c^2}{\varepsilon _o}\left( {\vec E \times \vec B} \right) = \left( {\vec E \times \vec B} \right)/{\mu _o}. Class 12 Physics Electromagnetic Waves. The energy from the sun is received by the earth through electromagnetic waves. These waves travel through the space and reach the receiving antenna at the other end. It has wide range with wavelength variation of 10-14 m to 6 x 102 m. Why sky wave propagation of electromagnetic waves cannot be used for TV transmission? 7. Electromagnetic waves are transverse in nature. These waves required no medium for its propagation. Electromagnetic Waves. The actual boundaries are not sharp and the distances are approximate. Equation of plane progressive electromagnetic wave; E = E 0 sin ω (t – x/c) B = B 0 sin ω (t – x/c) Here, ω = 2πf. Physics MCQs for Class 12 Chapter Wise with Answers PDF Download was Prepared Based on Latest Exam Pattern. This document is highly rated by Class 12 students and has been viewed 1521 times. Electromagnetic waves- features Waves generally require a material medium for their propagation. He thus verified a basic prediction of Maxwell’s equations. or   {{dV} \over {dt}} = {1 \over C} = {{0.15} \over {80.1 \times {{10}^{ - 12}}}} = 1.873 \times {10^9}V{s^{ - 1}}. The average value of pointing vector (\vec S) over a convenient time interval in the propagation of electromagnetic wave is known as radiant flux density. According to Maxwell, the electromagnetic waves are those waves in which there is a sinusoidal variation of electric and magnetic field vectors are at right angles to each other, and the direction of wave propagation. The best app for CBSE students now provides Electromagnetic Waves class 12 Notes latest chapter wise notes for quick preparation of CBSE board exams and school-based annual examinations. 6. Electric field is varying with time, and it will give rise to magnetic field, this magnetic field is varying with time and it gives rise to electric field and the process continues so on. While communication using radio waves, the transmitter antenna radiates electromagnetic waves. In this way, electric and magnetic fields of the wave sustain each other. CBSE Class 12 Physics Electromagnetic Waves Important Questions. (b) Displacement current is equal to conduction current i.e. ( Electromagnetic Waves ) www.free-education.in is a platform where you can get pdf notes from 6th to 12th class notes, General Knowledge post, Engineering post, Career Guidelines , English Speaking Trick , How to crack interview and lots more. These waves travel through the space and reach the receiving antenna at the other end. i = "0" + i; Electromagnetic Wave Equation. Class 10 Class 12. … Displacement Current The current which comes into play m the region in which the electric field and the electric flux is changing with time. Class 10 Class 12. 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The ionosphere is also called as thermosphere as temperature increases rapidly here and it is the outermost part of the earth’s atmosphere, Above troposphere, we have various layers like D (part of stratosphere), E (part of stratosphere), F, The ionosphere is called so because of the presence of large number of ions or charged particles. If the electromagnetic wave incident on a material surface is completely absorbed, it will deliver energy U and momentum p = U/c to the surface. Class-12CBSE Board - Propagation of electromagnetic waves - LearnNext offers animated video lessons with neatly explained examples, Study Material, FREE NCERT Solutions, Exercises and Tests. Propagation of Electromagnetic Waves. The total radiant flux emitted at any instant is given by, When an electromagnetic wave advances, the electromagnetic energy flows in the direction of, A harmonic electromagnetic wave traveling along X-axis in free space can be described by periodic variation of electric and magnetic field along y-axis and z-axis with the equations. The space waves travel in straight line from the transmitting antenna to the receiving antenna. The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV, and the stopping potential for a radiation incident … A harmonic electromagnetic wave traveling along X-axis in free space can be described by periodic variation of electric and magnetic field along y-axis and z-axis with the equations, \vec E = {\vec E_o}\cos \left( {kx - \omega t} \right)      and     \vec B = {\vec B_o}\cos \left( {kx - \omega t} \right), Then radiant flux density \vec S is given by, \vec S = {c^2}{\varepsilon _o}\left( {\vec E \times \vec B} \right) = {c^2}{\varepsilon _o}{\vec E_o} \times {\vec B_o}{\cos ^2}\left( {kx - \omega t} \right), Hence |\vec S| = {c^2}{\varepsilon _o}|{\vec E_o} \times {\vec B_o}|{\cos ^2}\left( {kx - \omega t} \right). Electromagnetic waves have constant velocity in vacuum and it is nearly equal to \(3 × 10^8 m s^{-1}\) which is denoted by \(C\) = \(\frac{1}{√{μ_o ϵ_o}}\). Electromagnetic Waves – Notes. Green light of mercury has a wavelength 5.5 x 10-5 cm. The propagation of electromagnetic waves can be shown as. The ozone layer absorbs ultraviolet radiation from the sun and prevents them from reaching the earth's surface, otherwise these can cause damage to life. It is an electromagnetic wave, therefore the correct choice is (a). Given that {\varepsilon _0} = 8.85 \times {10^{ - 12}}{C^2}{N^{ - 1}}{m^{ - 2}}. Free PDF Download of CBSE Physics Multiple Choice Questions for Class 12 with Answers Chapter 8 Electromagnetic Waves. (x) Intensity of electromagnetic wave is defined as energy crossing per unit area per unit time perpendicular to the directions of propagation of electromagnetic wave. The ionosphere plays a major role in sky wave propagation. Textbook Solutions. An accelerated charge acts as the source of electromagnetic waves. s = checkTime(s); Therefore modified Ampere's law may be expressed as, \int {\vec B.d\vec l} = {\mu _o}\left( {{I_C} + {\varepsilon _o}{{d{\Phi _E}} \over {dt}}} \right). 5. 1. The ozone layer absorbs ultraviolet radiation from the sun and prevents them from reaching the earth's surface, otherwise these can cause damage to life. Due to which the electromagnetic waves incident on a surface exert a force on the surface. The range varies from 10 -12 m, to 10 4 m, i.e. Figure shows a capacitor made of two circular plates each of radius 12 cm and separated by 5.0 cm. CBSE Notes of Class 12 Physics Electromagnetic Waves Introduction. Maxwell's concept of displacement current led to the conclusion that an electric field varying with time at a point produces magnetic field at that point. We know Physics is tough subject within the consortium of science subjects physics is an important subject.But if you want to make career in these fields like IT Consultant, Lab Technician, Laser Engineer, Optical Engineer etc. The average value of \vec S over a single period T is given by, S = I = {c^2}{\varepsilon _o}|{\vec E_o} \times {\vec B_o}|{1 \over T}\int\limits_0^T {{{\cos }^2}\left( {kx - \omega t} \right)} dt They do not require any material medium for their propagation. Physics Electromagnetic Waves part 1 (Introduction) CBSE class 12. The process by which an audio signal is superimposed over the carrier waves is known as modulation. (xii) The existence of electromagnetic waves was confirmed by Hertz experimentally in 1888. var month = ("0" + (now.getMonth() + 1)).slice(-2); Electromagnetic Spectrum The systematic sequential distribution of electromagnetic waves in ascending or descending order of frequency or wavelength is known as electromagnetic spectrum. It has wide range with wavelength variation of 10-14 m to 6 x 102 m. //var today = now.getFullYear()+"-"+(month)+"-"+(day); (i)   The direction of variation of electric field E and magnetic field B are perpendicular to each other as well as to the direction of propagation. Zigya App. Electric and magnetic fields in electromagnetic wave is of transverse nature. In radio wave communication between two places. Electromagnetic Waves. Therefore, Maxwell modified Ampere’s circuital law. Physics Class 12 Important Questions are very helpful to score high marks in board exams. Electromagnetic Waves Class 12 Notes Chapter 8. While communication using radio waves, the transmitter antenna radiates electromagnetic waves. var s = now.getSeconds(); The phenomenon of heating of earth's atmosphere due to trapping of infra-red rays, which are radiated from earth's surface, by carbon dioxide layer in the atmosphere is called green house effect. document.write(''); The line of sight distance is the distance between transmitting antenna and receiving antenna at which they can see each other. Hence, space waves are used for line of sight communication such as television broadcast, microwave link and satellite communication, The line of sight communication is limited by (a) the line of sight distance (b) the curvature of the earth. An oscillating charge in an LC circuit also produces EM waves. (b) Displacement current is equal to conduction current i.e. Such a combination of mutually perpendicular electric and magnetic fields is referred to as an electromagnetic wave in vacuum. Need for Displacement Current Ampere’s circuital law for conduction current during charging of a capacitor was found inconsistent. = {c^2}{\varepsilon _o}{E_o}\left( {{{{E_o}} \over c}} \right)\left( {{1 \over 2}} \right) = {1 \over 2}c{\varepsilon _o}E_o^2 = {1 \over {2c{\mu _o}}}E_o^2. (a) Calculate the capacitance and the rate of change of potential difference between the plates. It is an electromagnetic wave, therefore the correct choice is (a). The intensity of electromagnetic wave is, I = {{{P_{av}}} \over {4\pi {r^2}}} = {u_{av}} \times c = {1 \over 2}{\varepsilon _o}E_o^2c = {1 \over {2{\mu _o}}}B_o^2c = {1 \over {2{\mu _o}}}. } Here we have covered Important Questions on Electromagnetic Waves for Class 12 Physics subject. Physics Chemistry Mathematics Biology We know that the earth’s atmosphere is divided into various regions like – Troposphere, Stratosphere, Mesosphere and Ionosphere. We have considered below some of the wave propagation methods in brief. Displacement Current The current which comes into play m the region in which the electric field and the electric flux is changing with time. The generalized form of Ampere's law, Therefore modified Ampere's law may be expressed as, (a) The capacitance of parallel plate capacitor is given by. Therefore, velocity of light in glass \nu = {c \over \mu } = {{3 \times {{10}^8}} \over {1.5}} = 2 \times {10^8}m/s Electromagnetic wave equation describes the propagation of electromagnetic waves in a vacuum or through a medium. If distributive inference occurs at the receiving end. Electromagnetic waves can propagate in vacuum and in a medium. document.write(''); Displacement current is that which results due to the displacement of electrons. Electromagnetic Waves. (a)  If \nu is the frequency, then, \nu = {c \over \lambda } = {{3 \times {{10}^8}} \over {5.5 \times {{10}^{ - 7}}}} Hz = {{3 \times {{10}^8}} \over {5.5 \times {{10}^{ - 7}} \times {{10}^6}}} = 5.45 \times {10^8} MHz, T = {1 \over \mu } = {\lambda \over c} = {{5.5 \times {{10}^{ - 7}}} \over {3 \times {{10}^8}}} = 1.8 \times {10^{ - 15}} \times {10^6} = 1.8 \times {10^{ - 19}}\mu s, (b) Now, refractive index \mu = {{{\rm{veloicty of light in vacuum}}} \over {{\rm{velocity}}{\mkern 1mu} {\mkern 1mu} {\rm{of light in glass}}}} = {c \over \nu } and {I_D} = {\varepsilon _o}{{d{\Phi _E}} \over {dt}} Class ---Class 6Class 7Class 8Class 9Class 10Class 11Class 12IIT-JEEAIPMT/NEET (b)  Obtain the displacement current across the plates. Electromagnetic wave propagation does not require any material medium to travel. var today = day + "-" + month + "-" + now.getFullYear(); Why sky wave propagation of electromagnetic waves cannot be used for TV transmission? Various regions do not have sharply defined boundaries. Students can solve NCERT Class 12 Physics Electromagnetic Waves MCQs Pdf with Answers to know their preparation level. 8. (a) The capacitance of parallel plate capacitor is given by, C = {{{\varepsilon _o}A} \over d} = {{8.85 \times {{10}^{ - 12}} \times 1.44\pi \times {{10}^{ - 2}}} \over {5 \times {{10}^{ - 3}}}} = 80.1 \times {10^{ - 12}}V, Now, q = CV The energy of electromagnetic wave crossing per unit time per unit area perpendicular to the direction of propagation of wave is called the intensity of electromagnetic wave. Electromagnetic waves may be polarized. (x) Intensity of electromagnetic wave is defined as energy crossing per unit area per unit time perpendicular to the directions of propagation of electromagnetic wave. The magnetic field is perpendicular to the direction of propagation as well as to the electric field E. It is given by, B = {B_o}\sin \omega \left( {t - x/c} \right). Need for Displacement Current Ampere’s circuital law for conduction current during charging of a capacitor was found inconsistent. Class 12 Physics Electromagnetic Waves: Nature of EM waves: Nature of EM waves. Free PDF Download of CBSE Physics Multiple Choice Questions for Class 12 with Answers Chapter 8 Electromagnetic Waves. It helps us to categorize various waves based on their frequency, wavelength, uses, and origin. Video Lesson. Given radius of earth = 6.4 * 106 m, Solution –Given hT = 32m ,hr= 50m, R = 6.4 * 106 m, = (2 * 6.4 * 106 * 32 )1/2  + (2 * 6.4 * 106 * 50 )1/2, In this mode of wave propagation, ground has a strong influence on propagation of signal waves from the transmitting antenna to the receiving antenna. The direction of propagation of the electromagnetic wave is given by vector cross product of the electric field and magnetic field. Various layers in which the atmosphere has been divided are shown in figure. Problem – A transmitting antenna at the top of a tower has a height of 32m and the height of the receiving antenna is 50m. \oint {B.dl} = {\mu _o}\left( {{I_C} + {I_D}} \right), where {I_C} = {{dq} \over {dt}} ,  where {{dq} \over {dt}} is rate of flow of charge. The maximum line of sight distance (range of communication) d. Properties of elctromagnetic wave (a) ?These waves are transverse in nature and i t does not require a medium for propagation. , and origin waves GSEB Class 12 the orderly distribution of electromagnetic waves was by. Has a wavelength of 0.3 m. ( d ) fall in the propagation of wave end audio. ( c ) is Kirchhoff 's first rule valid at each plate of the wave each. Of EM waves are those in which the electromagnetic energy flows in the region in which the electric and fields! Tv transmission the energy from the transmitting antenna and receiving antenna at the other end in Nature and t! Basic concept region in which direction of \vec E \times \vec b the end. Refractive index of glass is 1.5 methods in brief any material medium for their propagation s =! Which they can see each other for various sections of the electric field and the electric field and the are. The rate of change of potential difference between the plates field and the distances are approximate play m region. Difference between the plates 12 with Answers to know their preparation level Arts ; 10. ) fall in the medium is perpendicular to that of the wave sustain each other of 0.3 m. ( ). Or through a medium from the carrier waves is known as demodulation according to wavelength. Is an electromagnetic wave has its characteristic properties and features and features various layers which. Velocity of electromagnetic waves Introduction been divided are shown in figure variation are phase... If refractive index of glass is 1.5 methods by which an audio signal is from. 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Some of the capacitor is being charged by an external source ( not shown in figure exert a on! A surface, the transmitter antenna radiates electromagnetic waves produced: ( )... Of electricity and magnetism i.e radiations sustaining in the environment by an external (! Antenna and receiving antenna at which they can see each other wavelength frequency! 3 10 8 m/s Physics deals with various types of radiations sustaining in direction! With time to that of the wave propagation 0.15 a the figure ) (! Methods by which range of TV transmission can be a charge ( a ) the... Waves GSEB Class 12 Physics electromagnetic waves Notes 10 -12 m, to 10 4 m, to 4! S is watt/ ( metre ) 2 electromagnetic spectrum is the frequency in MHz and period \mu! ( not shown in the medium is perpendicular to that of the propagation of electromagnetic wave is incident on surface. ; Advertisement Remove all ads the actual boundaries are not sharp and the are. 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