12P08
Electromagnetic Waves
12P08-Electromagnetic Waves
Learning Objectives
Displacement current
Electromagnetic waves
Electromagnetic spectrum
12P08.1
Displacement current
12P08.1 Displacement current
Learning Objectives
Maxwell’s argument
Maxwell’s experiment
Maxwell’s equation
12P08.1
CV1
Maxwell’s arguments
Motion of charge
Effects of motion of a charge
Motion of charge
Effects of motion of a charge
Stationary
Motion of charge
Effects of motion of a charge
Stationary
Electric field is generated
Motion of charge
Effects of motion of a charge
Stationary
Electric field is generated
Motion of charge
Effects of motion of a charge
Stationary
Moving with uniform motion
Electric field is generated
Motion of charge
Effects of motion of a charge
Stationary
Moving with uniform motion
Magnetic field is generated
Electric field is generated
Motion of charge
Effects of motion of a charge
Stationary
Moving with uniform motion
Magnetic field is generated
Electric field is generated
Motion of charge
Effects of motion of a charge
Stationary
Moving with uniform motion
Accelerated
Magnetic field is generated
Electric field is generated
Motion of charge
Effects of motion of a charge
EM Waves are generated
Stationary
Moving with uniform motion
Accelerated
Magnetic field is generated
Electric field is generated
Maxwell’s argument
Current creates magnetic fields.
Hans Oersted
Maxwell’s argument
Current creates magnetic fields.
Oersted's experiment
Hans Oersted
Maxwell’s argument
Magnetic field changing with time gives rise to an electric field.
Michael Faraday
Maxwell’s argument
Magnetic field changing with time gives rise to an electric field.
Faraday’s law
Michael Faraday
Maxwell’s argument
Is the converse also true?
Maxwell’s argument
Is the converse also true?
J.C. Maxwell
Maxwell’s argument
Does the change in electric field create magnetic field?
J.C. Maxwell
Maxwell’s argument
A time varying electric field can generate magnetic field.
Maxwell’s argument
A time varying electric field can generate magnetic field.
Maxwell’s argument
A time varying electric field can generate magnetic field.
Ic
Ic
Maxwell’s argument
A time varying electric field can generate magnetic field.
Ic
Ic
Maxwell’s argument
A time varying electric field can generate magnetic field.
Ic
Ic
Maxwell’s argument
Electric field
Maxwell’s argument
Electric field
Electric field changing with time gives rise to a magnetic field.
Maxwell’s argument
Electric field
Magnetic field
Electric field changing with time gives rise to a magnetic field.
Maxwell’s argument
Electric field
Magnetic field
Electric field changing with time gives rise to a magnetic field.
Magnetic field changing with time gives rise to an electric field.
12P08.1
CV2
Maxwell’s Experiment
Maxwell’s experiment (outside the capacitor)
Case 1:
Maxwell’s Experiment
Maxwell’s experiment (outside the capacitor)
Case 1:
Parallel Plate
Capacitor
Maxwell’s experiment (outside the capacitor)
Case 1:
Parallel Plate
Capacitor
Compass is outside
Maxwell’s experiment (outside the capacitor)
Case 1:
Parallel Plate
Capacitor
Compass is outside
Compass gets deflected
Maxwell’s experiment (outside the capacitor)
Case 1:
Parallel Plate
Capacitor
Compass is outside
Compass gets deflected
Magnetic field is present
Maxwell’s experiment (outside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (outside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (outside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (outside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (inside the capacitor)
Case 2:
Maxwell’s Experiment
Maxwell’s experiment (inside the capacitor)
Case 2:
Parallel Plate
Capacitor
Maxwell’s experiment (inside the capacitor)
Case 2:
Parallel Plate
Capacitor
Compass is inside
Maxwell’s experiment (inside the capacitor)
Case 2:
Parallel Plate
Capacitor
Compass is inside
Compass gets deflected
Maxwell’s experiment (inside the capacitor)
Case 2:
Parallel Plate
Capacitor
Compass is inside
Compass gets deflected
Magnetic field is present
Maxwell’s experiment (inside the capacitor)
Case 2:
Parallel Plate
Capacitor
Compass is inside
Compass gets deflected
Magnetic field is present
Current is present
Maxwell’s experiment (inside the capacitor)
Apply Ampere’s law
Closed loop
4.31
Parallel Plate
Capacitor
Maxwell’s experiment (inside the capacitor)
Apply Ampere’s law
Closed loop
4.31
Parallel Plate
Capacitor
Maxwell’s experiment (inside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (inside the capacitor)
Apply Ampere’s law
Closed loop
Parallel Plate
Capacitor
Maxwell’s experiment (Conclusion)
Change in electric field produces magnetic field which suggest presence of current that is called displacement current.
Ic
Ic
Parallel plate capacitor
Maxwell’s experiment (Conclusion)
Change in electric field produces magnetic field which suggest presence of current that is called displacement current.
Ic
Ic
Maxwell’s experiment (Conclusion)
Change in electric field produces magnetic field which suggest presence of current that is called displacement current.
Ic
Ic
Maxwell’s experiment (Conclusion)
Change in electric field produces magnetic field which suggest presence of current that is called displacement current.
Id
Ic
Ic
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Using Gauss’s law flux passing through plates
Parallel Plate
Capacitor
Closed loop
Displacement current
Parallel Plate
Capacitor
Closed loop
Displacement current
Parallel Plate
Capacitor
Closed loop
Displacement current
Parallel Plate
Capacitor
Closed loop
Displacement current
Parallel Plate
Capacitor
Closed loop
Displacement current
Parallel Plate
Capacitor
Closed loop
Id
Displacement current
Total current
Parallel Plate
Capacitor
Closed loop
Displacement current
Total current
Parallel Plate
Capacitor
Closed loop
Id = 0
Displacement current
Total current
Parallel Plate
Capacitor
Closed loop
Id = 0
Ic = 0
Id = Ic
Id
Displacement current
Maxwell Ampere’s law
Displacement current
Maxwell Ampere’s law
Displacement current
Maxwell Ampere’s law
Where Ic = Conduction current
Displacement current
Maxwell Ampere’s law
Where Ic = Conduction current
Id = Displacement current
Displacement current
Definition
Current flowing between the capacitor plates without motion of charges is called displacement current.
Displacement current between capacitor plates
Displacement current
Definition
Current flowing between the capacitor plates without motion of charges is called displacement current.
Current arises due to changing of electric field.
Displacement current
Definition
Current flowing between the capacitor plates without motion of charges is called displacement current.
Current arises due to changing of electric field.
Displacement current
Displacement current
Definition
Current flowing between the capacitor plates without motion of charges is called displacement current.
Current arises due to changing of electric field.
Displacement current
Displacement current
Definition
Current flowing between the capacitor plates without motion of charges is called displacement current.
Current arises due to changing of electric field.
Displacement current
ConcepTest
Ready for challenge
Q. The charge on a parallel plate capacitor varies as . The plates are very large and close together (Area = A, Separation = d). Neglecting the edge effect find the displacement current through the capacitor?
Q. The charge on a parallel plate capacitor varies as . The plates are very large and close together (Area = A, Separation = d). Neglecting the edge effect find the displacement current through the capacitor?
Pause video
(Time duration : 2 minutes)
Sol.
Parallel plate capacitor
Plate area (A)
Sol. Displacement current
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
Sol. Displacement current
Electric field
Plate area (A)
12P08.1
CV3
Maxwell’s Equation
Maxwell’s Equation
Electric field exists due to charge.
Maxwell’s Equation
Electric field exists due to charge.
2. (Gauss’s Law for magnetism)
Magnetic field lines form closed loop.
Maxwell’s Equation
3. (Faraday’s Law)
Electric field is generated due to change of magnetic field.
Maxwell’s Equation
3. (Faraday’s Law)
Electric field is generated due to change of magnetic field.
4. (Maxwell-Ampere’s Law)
Magnetic field generates due to change of electric field.
Reference Questions
NCERT : Ex 8.1
12P08.1
PSV 1
Q. Figure shows a capacitor made of two circular plate each of radius 12 cm , and separated by 5.0 cm . The capacitor is being charged by an external source (not shown in figure). The charging current is constant and equal to 0.15 A .
Parallel plate capacitor
Q. Figure shows a capacitor made of two circular plate each of radius 12 cm , and separated by 5.0 cm . The capacitor is being charged by an external source (not shown in figure). The charging current is constant and equal to 0.15 A .
Parallel plate capacitor
Q. Figure shows a capacitor made of two circular plate each of radius 12 cm , and separated by 5.0 cm . The capacitor is being charged by an external source (not shown in figure). The charging current is constant and equal to 0.15 A .
Parallel plate capacitor
Q. Figure shows a capacitor made of two circular plate each of radius 12 cm , and separated by 5.0 cm . The capacitor is being charged by an external source (not shown in figure). The charging current is constant and equal to 0.15 A .
Parallel plate capacitor
Sol.
Separation d = 5 cm
Radius of plate r = 12 cm
Parallel plate capacitor
Sol.
Separation d = 5 cm
Radius of plate r = 12 cm
Parallel plate capacitor
Sol.
Separation d = 5 cm
Radius of plate r = 12 cm
Parallel plate capacitor
Sol.
Separation d = 5 cm
Radius of plate r = 12 cm
Parallel plate capacitor
Sol.
Separation d = 5 cm
Radius of plate r = 12 cm
Parallel plate capacitor
Rate of change of potential difference = = ?
Rate of change of potential difference = = ?
Given
I = 0.15 A
Rate of change of potential difference = = ?
Given
I = 0.15 A
Rate of change of potential difference = = ?
Given
I
I = 0.15 A
Rate of change of potential difference = = ?
Given
I
I
I = 0.15 A
Rate of change of potential difference = = ?
Given
I
I
I
I = 0.15 A
Given
I = 0.15 A
Given
I = 0.15 A
Given
I = 0.15 A
Given
I = 0.15 A
Given
I = 0.15 A
Given
I
= Id
0.15 A
I = 0.15 A
Yes, kirchoff’s law is valid at each plate of capacitor.
Yes, kirchoff’s law is valid at each plate of capacitor.
As we know that kirchoff’s law states that algebraic sum of currents at any junction of circuit must be zero.
Yes, kirchoff’s law is valid at each plate of capacitor.
As we know that kirchoff’s law states that algebraic sum of currents at any junction of circuit must be zero.
At point A apply kirchoff’s law
Ic
Ic
Id
A
Parallel plate capacitor
Yes, kirchoff’s law is valid at each plate of capacitor.
As we know that kirchoff’s law states that algebraic sum of currents at any junction of circuit must be zero.
At point A apply kirchoff’s law
Ic
Ic
Id
A
Yes, kirchoff’s law is valid at each plate of capacitor.
As we know that kirchoff’s law states that algebraic sum of currents at any junction of circuit must be zero.
At point A apply kirchoff’s law
Ic
Ic
Id
A
Yes, kirchoff’s law is valid at each plate of capacitor.
As we know that kirchoff’s law states that algebraic sum of currents at any junction of circuit must be zero.
At point A apply kirchoff’s law
Ic
Ic
Id
A
Summary
12P08.2
Electromagnetic Waves
12P08.2 Electromagnetic waves
Learning Objectives
What is EM Waves
Source and Nature of EM Waves
Properties of EM Waves
12P08.2
CV1
What is EM Waves
What is EM Waves
What is Wave?
Disturbance that travels through a medium or without medium, transporting energy from one location to another location without transporting medium.
Wave
What is EM Waves
Types of waves
130
What is EM Waves
Types of waves
Example : Sound waves
131
Longitudinal wave
What is EM Waves
What is EM Waves
Example : Waves of guitar’s string
Transverse wave
What is EM Waves
Definition of Electromagnetic waves
What is EM Waves
Definition of Electromagnetic waves
Electric field, magnetic field and direction of propagation of wave are mutually perpendicular.
Propagation direction
Z
What is EM Waves
Definition of Electromagnetic waves
Electric field, magnetic field and direction of propagation of wave are mutually perpendicular.
Electromagnetic waves are non material waves.
Propagation direction
Z
What is EM Waves
Definition of Electromagnetic waves
Electric field, magnetic field and direction of propagation of wave are mutually perpendicular.
Electromagnetic waves are non material waves.
Z
Y
X
Z
What is EM Waves
How EM Waves are produced?
An accelerated or oscillated charge generates EM Waves.
138
ret
Y
X
Z
Z
What is EM Waves
http://www.mysearch.org.uk/website1/images/animations/472.emwave.gif
Oscillating Charge
What is EM Waves
http://www.mysearch.org.uk/website1/images/animations/472.emwave.gif
Oscillating Charge
Oscillating Electric Field
What is EM Waves
http://www.mysearch.org.uk/website1/images/animations/472.emwave.gif
Oscillating Charge
Oscillating Magnetic Field
Oscillating Electric Field
What is EM Waves
http://www.mysearch.org.uk/website1/images/animations/472.emwave.gif
Oscillating Charge
Oscillating Electric Field
Oscillating Magnetic Field
Oscillating Electric Field
What is EM Waves
Oscillating Electric Field
What is EM Waves
Oscillating Magnetic Field
Oscillating Electric Field
What is EM Waves
Oscillating magnetic field
Oscillating electric field
EM Waves
Oscillating Magnetic Field
Oscillating Electric Field
ConcepTest
Ready for challenge
Q. A plane EM Waves travels in vacuum along z - direction. What can you say about the directions of its electric and magnetic field vectors?
Q. A plane EM Waves travels in vacuum along z - direction. What can you say about the directions of its electric and magnetic field vectors?
Pause video
(Time duration : 2 minutes)
Q. A plane EM Waves travels in vacuum along z - direction. What can you say about the directions of its electric and magnetic field vectors?
Sol. Electric field and magnetic field are in x-y plane and perpendicular to each other as shown below in figure.
Q. A plane EM Waves travels in vacuum along z - direction. What can you say about the directions of its electric and magnetic field vectors?
Sol. Electric field and magnetic field are in x-y plane and perpendicular to each other as shown below in figure.
Z
X
Y
Propagation direction
Q. A plane EM Waves travels in vacuum along z - direction. What can you say about the directions of its electric and magnetic field vectors?
Sol. Electric field and magnetic field are in x-y plane and perpendicular to each other as shown below in figure.
E or B
B or E
Velocity of wave
Z
X
Y
X
Y
Z
Propagation direction
12P08.2
CV2
Source and Nature of EM Waves
Source and Nature of EM Waves
Source of Electromagnetic waves:
Source of electromagnetic wave is a vibrating or accelerating charge or oscillating charge.
Source and Nature of EM Waves
Source of Electromagnetic waves:
Source of electromagnetic wave is a vibrating or accelerating charge or oscillating charge.
Change in Electric Field
Source and Nature of EM Waves
Source of Electromagnetic waves:
Source of electromagnetic wave is a vibrating or accelerating charge or oscillating charge.
Change in Electric Field
Change in Magnetic Field
Source and Nature of EM Waves
Source of Electromagnetic waves:
Source of electromagnetic wave is a vibrating or accelerating charge or oscillating charge.
Change in Electric Field
Change in Magnetic Field
Source and Nature of EM Waves
Nature of EM Waves
EM Waves are transverse and non material waves .
Source and Nature of EM Waves
Equation of electromagnetic waves
Representation of EMW
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Here ⍵ = angular frequency(rad/sec)
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Here ⍵ = angular frequency(rad/sec)
k = magnitude of wave vector
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Here ⍵ = angular frequency(rad/sec)
k = magnitude of wave vector
λ = wavelength of EMWs
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Here ⍵ = angular frequency(rad/sec)
k = magnitude of wave vector
λ = wavelength of EMWs
z = propagation direction
Z
Propagation direction
Source and Nature of EM Waves
Equation of electromagnetic waves
Here ⍵ = angular frequency(rad/sec)
k = magnitude of wave vector
λ = wavelength of EMWs
z = propagation direction
t = specific time
Z
Propagation direction
Source and Nature of EM Waves
c = speed of electromagnetic wave = speed of light = 3 × 108 m/sec
Source and Nature of EM Waves
Magnitude of wave propagation vector
Source and Nature of EM Waves
Relationship between permittivity ( 𝟄0 ) of free space and magnetic permeability of free space ( 𝝻0 )
Source and Nature of EM Waves
For any other material the velocity of EM Waves
Source and Nature of EM Waves
For any other material the velocity of EM Waves
Source and Nature of EM Waves
For any other material the velocity of EM Waves
Where 𝟄 and 𝝻 are permittivity and permeability of material respectively.
ConcepTest
Ready for challenge
Q. The source of EM Waves can be a charge
Q. The source of EM Waves can be a charge
Pause video
(Time duration : 2 minutes)
Q. The source of EM Waves can be a charge
Sol.
(b) Moving in a circular orbital ( In circular motion a particle is having centripetal acceleration so it can be a source of EM Waves )
(d) Falling in an electric field (In electric field a charge particle is experienced force so that it gets accelerated, so it can be a source EM Waves)
ConcepTest
Ready for challenge
Q. Which physical quantity is same for X- rays of wavelength 10 -10 m , red light of wavelength 6800 Å and radio waves of wavelength 500 m ?
Q. Which physical quantity is same for X- rays of wavelength 10 -10 m , red light of wavelength 6800 Å and radio waves of wavelength 500 m ?
Pause video
(Time duration : 2 minutes)
Q. Which physical quantity is same for X- rays of wavelength 10 -10 m , red light of wavelength 6800 Å and radio waves of wavelength 500 m ?
Sol.
ConcepTest
Ready for challenge
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Pause video
(Time duration : 2 minutes)
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
Q. A radio can tune in to any station in the 7.5 MHz to 12 MHz band. What is the corresponding wavelength band?
Sol. We know that
So that corresponding wavelength band 40 m to 25 m.
ConcepTest
Ready for challenge
Q. A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. what is the frequency of the electromagnetic waves produced by the oscillator?
Q. A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. what is the frequency of the electromagnetic waves produced by the oscillator?
Pause video
(Time duration : 2 minutes)
Q. A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. what is the frequency of the electromagnetic waves produced by the oscillator?
Sol. Frequency of Electromagnetic wave must be equal to the frequency of oscillation of charged particle.
So frequency of EM Waves is 10 9 Hz.
12P08.2
CV3
Properties of EM Waves
Properties of EM Waves
Electromagnetic waves are transverse in nature.Properties of EMWs
Transverse wave
Properties of EM Waves
Speed of EM Waves is equal to the speed of light.
Properties of EM Waves
Speed of EM Waves is equal to the speed of light.
c = speed of wave in vacuum = 3 × 10 8 m/s
Characteristics of EMW
Properties of EM Waves
Speed of EM Waves is equal to the speed of light.
c = speed of wave in vacuum = 3 × 10 8 m/s
λ = wavelength of EM Waves
Characteristics of EMW
Properties of EM Waves
Speed of EM Waves is equal to the speed of light.
c = speed of wave in vacuum = 3 × 10 8 m/s
λ = wavelength of EM Waves
A = amplitude of wave
Characteristics of EMW
Properties of EM Waves
Speed of EM Waves is equal to the speed of light.
c = speed of wave in vacuum = 3 × 10 8 m/s
λ = wavelength of EM Waves
A = amplitude of wave
𝝂 = frequency of wavelength
Characteristics of EMW
Properties of EM Waves
Velocity of EM Waves
Properties of EM Waves
Relationship between magnitude of electric field and magnetic field
Properties of EM Waves
Relationship between magnitude of electric field and magnetic field
Where E0 = Maximum value of electric field
Properties of EM Waves
Relationship between magnitude of electric field and magnetic field
Where E0 = Maximum value of electric field
B0 = Maximum value of magnetic field
Properties of EM Waves
Poynting vector:- The rate of flow of energy in an electromagnetic wave per unit area per unit second is called poynting vector.
Properties of EM Waves
Poynting vector:- The rate of flow of energy in an electromagnetic wave per unit area per unit second is called poynting vector.
Representation of poynting vector
Properties of EM Waves
Poynting vector:- The rate of flow of energy in an electromagnetic wave per unit area per unit second is called poynting vector.
Representation of poynting vector in circuit
Properties of EM Waves
Poynting vector:- The rate of flow of energy in an electromagnetic wave per unit area per unit second is called poynting vector.
Representation of poynting vector in circuit
Properties of EM Waves
Poynting vector:- The rate of flow of energy in an electromagnetic wave per unit area per unit second is called poynting vector.
SI Unit of S is watt / m2.
Representation of poynting vector in circuit
Properties of EM Waves
The electric vector is responsible for optical effect of electromagnetic waves.
Properties of EM Waves
The electric vector is responsible for optical effect of electromagnetic waves.
Because moving particle oscillates primarily due to the electric field.
Properties of EM Waves
The energy in an electromagnetic wave is equally divided in electric vector and magnetic vector.
Properties of EM Waves
The energy in an electromagnetic wave is equally divided in electric vector and magnetic vector.
Energy distribution in EMWs
Properties of EM Waves
The Average energy density of electric field
Properties of EM Waves
The Average energy density of magnetic field
Properties of EM Waves
Intensity of EM Waves is defined as the energy crossing per unit area per unit time perpendicular to the propagation of electromagnetic wave.
Properties of EM Waves
Intensity of EMWs is defined as the energy crossing per unit area per unit time perpendicular to the propagation of electromagnetic wave.
Properties of EM Waves
The existence of EM Waves was confirmed by Hertz in 1888.
Heinrich hertz
Properties of EM Waves
Total momentum delivered to surface by EM Waves
Properties of EM Waves
Total momentum delivered to surface by EM Waves
p = Total momentum delivered
Properties of EM Waves
Total momentum delivered to surface by EM Waves
p = Total momentum delivered
U = Total energy of EM Waves
Properties of EM Waves
Total momentum delivered to surface by EM Waves
p = Total momentum delivered
U = Total energy of EM Waves
c = Speed of light
ConcepTest
Ready for challenge
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Pause video
(Time duration : 2 minutes)
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Sol. Given
B0 = 510 nT
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Sol. Given
B0 = 510 nT
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Sol. Given
B0 = 510 nT
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Sol. Given
B0 = 510 nT
Q. The amplitude of the magnetic field part of a harmonic electromagnetic wave in vacuum is 510 nT. What is the amplitude of the electric field part of the wave?
Sol. Given
B0 = 510 nT
Reference Questions
NCERT : Example 8.2, 8.3, 8.4, 8.5
12P08.2
PSV 2
Q. Suppose that the electric field amplitude of an electromagnetic wave is E0 = 120 N/C and that its frequency is f = 50 MHz.
Q. Suppose that the electric field amplitude of an electromagnetic wave is E0 = 120 N/C and that its frequency is f = 50 MHz.
Q. Suppose that the electric field amplitude of an electromagnetic wave is E0 = 120 N/C and that its frequency is f = 50 MHz.
Q. Suppose that the electric field amplitude of an electromagnetic wave is E0 = 120 N/C and that its frequency is f = 50 MHz.
Pause video
(Time duration : 2 minutes)
Sol.
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Angular frequency
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Angular frequency
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Angular frequency
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Angular frequency
Given
E0 = 120 N/C
f = 50 MHz
Sol. Wavelength
Given
E0 = 120 N/C
f = 50 MHz
Sol. Wavelength
Given
E0 = 120 N/C
f = 50 MHz
Sol. Wavelength
Given
E0 = 120 N/C
f = 50 MHz
Sol. Wavelength
Given
E0 = 120 N/C
f = 50 MHz
Sol. Magnitude of propagation vector
Given
E0 = 120 N/C
f = 50 MHz
Sol. Magnitude of propagation vector
Given
E0 = 120 N/C
f = 50 MHz
Sol. Magnitude of propagation vector
Given
E0 = 120 N/C
f = 50 MHz
Sol. Magnitude of propagation vector
Given
E0 = 120 N/C
f = 50 MHz
E0 = 120 N/C
f = 50 MHz
Sol.
(b) Expression of electric field
Given
Sol.
(b) Expression of electric field
Given
E0 = 120 N/C
f = 50 MHz
Sol.
(b) Expression of electric field
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Expression of magnetic field
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Expression of magnetic field
Given
E0 = 120 N/C
f = 50 MHz
Sol.
Expression of magnetic field
Given
E0 = 120 N/C
f = 50 MHz
12P08.2
PSV 3
Q. A parallel plate capacitor made of circular plates each of radius R = 6 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V AC supply with an angular frequency of 300 rad / sec .
Q. A parallel plate capacitor made of circular plates each of radius R = 6 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V AC supply with an angular frequency of 300 rad / sec .
Q. A parallel plate capacitor made of circular plates each of radius R = 6 cm has a capacitance C = 100 pF. The capacitor is connected to a 230 V AC supply with an angular frequency of 300 rad / sec .
Sol. Given
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
Sol. Given
We know that for an LC circuit
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
Sol. Given
We know that for an LC circuit
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
Sol. Given
We know that for an LC circuit
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
Sol. Given
We know that for an LC circuit
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
Sol. Given
We know that for an LC circuit
radius R = 6 cm
C = 100 pF
𝞈 = 300 rad / sec
Vrms= 230 V
(b) Is the conduction equal to the displacement current?
Sol.
12P08.2
PSV 4
Q. In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 10 10 Hz and amplitude 48 V/m.
Q. In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 10 10 Hz and amplitude 48 V/m.
Q. In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 10 10 Hz and amplitude 48 V/m.
Q. In a plane electromagnetic wave, the electric field oscillates sinusoidally at a frequency of 2.0 × 10 10 Hz and amplitude 48 V/m.
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol.
Given
𝜈 = 2.0 × 10 10
E0 = 48 V/m
Sol. (c) Energy density in electric field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Sol. (c) Energy density in electric field
Energy density
in magnetic field
Summary
12P08.3
Electromagnetic Spectrum
12P08.3 Electromagnetic Spectrum
Learning objectives
What is EM Spectrum?
Classification of EM Waves
12P08.3
CV1
What is EM Spectrum
What is EM spectrum
The arrange array of electromagnetic radiation in the sequence of their wavelength or frequency is called Electromagnetic spectrum.
What is EM spectrum
The arrange array of electromagnetic radiation in the sequence of their wavelength or frequency is called Electromagnetic spectrum.
This consists electromagnetic energy ranging from Gamma Rays to Radio waves.
What is EM spectrum
Electromagnetic spectrum
What is EM spectrum
Radio Waves | Microwave Waves | Infrared Waves | Visible Rays | UV Rays | X-Rays | Gamma Rays |
Relationship between Energy, Wavelength and Frequency for Electromagnetic spectrum
What is EM spectrum
Radio Waves | Microwave Waves | Infrared Waves | Visible Rays | UV Rays | X-Rays | Gamma Rays |
Wavelength (λ)
Relationship between Energy, Wavelength and Frequency for Electromagnetic spectrum
What is EM spectrum
Radio Waves | Microwave Waves | Infrared Waves | Visible Rays | UV Rays | X-Rays | Gamma Rays |
Wavelength (λ)
Energy (E)
Relationship between Energy, Wavelength and Frequency for Electromagnetic spectrum
Wavelength (λ)
What is EM spectrum
Radio Waves | Microwave Waves | Infrared Waves | Visible Rays | UV Rays | X-Rays | Gamma Rays |
Wavelength (λ)
Energy (E)
Frequency (f)
Relationship between Energy, Wavelength and Frequency for Electromagnetic spectrum
Wavelength (λ)
Memory based question
Ready for challenge
Q. Which electromagnetic wave has the shortest wavelength and highest frequency ?
Q. Which electromagnetic wave has the shortest wavelength and highest frequency ?
Pause video
(Time duration : 2 minutes)
Q. Which electromagnetic wave has the shortest wavelength and highest frequency ?
Sol.
Memory based question
Ready for challenge
Q. Electromagnetic waves that you can see are called
Q. Electromagnetic waves that you can see are called
Pause video
(Time duration : 2 minutes)
Q. Electromagnetic waves that you can see are called
Sol.
Memory based question
Ready for challenge
Q. Longest wavelength of spectrum
Q. Longest wavelength of spectrum
Pause video
(Time duration : 2 minutes)
Q. Longest wavelength of spectrum
Sol.
Memory based question
Ready for challenge
Q. Which colour has the shortest wavelength in visible light?
Q. Which colour has the shortest wavelength in visible light?
Pause video
(Time duration : 2 minutes)
Q. Which colour has the shortest wavelength in visible light?
Sol.
12P08.3
CV2
Classification of EM Spectrum
Classification of EM Waves
Classification of EM Waves
Production - Due to accelerated charge in wire or antena
Classification of EM Waves
Production - Due to accelerated charge in wire or antena
Wavelength range - Greater than 0.1 m
Classification of EM Waves
Production - Due to accelerated charge in wire or antena
Wavelength range - Greater than 0.1 m
Detection- Receiver’s Aerial
Classification of EM Waves
Classification of EM Waves
Application of Radio waves
Radio waves are used in radio and television communication systems.
Classification of EM Waves
Application of Radio waves
Radio waves are used in radio and television communication systems.
Radio waves are used in Cellular phones to transmit voice communication in the ultrahigh frequency band.
Classification of EM Waves
2. Microwaves
Classification of EM Waves
2. Microwaves
Production - Klystron valve or magnetron valve
Microwave oven
Classification of EM Waves
2. Microwaves
Production - Klystron valve or magnetron valve
Wavelength range - 0.1 m to 1 mm
Classification of EM Waves
2. Microwaves
Production - Klystron valve or magnetron valve
Wavelength range - 0.1 m to 1 mm
Detection - Point contact diodes
Classification of EM Waves
Application of microwaves
They are suitable for the radar systems used in aircraft navigation.
Classification of EM Waves
Application of microwaves
They are suitable for the radar systems used in aircraft navigation.
Microwave oven is an interesting domestic application of these waves.
Classification of EM Waves
3. Infrared rays
Classification of EM Waves
3. Infrared rays
Production - Vibration of atoms and molecules
Infrared wireless communication
Infrared rays generation
Classification of EM Waves
3. Infrared rays
Production - Vibration of atoms and molecules
Wavelength range - 1 mm to 700 nm
Infrared wireless communication
Classification of EM Waves
3. Infrared rays
Production - Vibration of atoms and molecules
Wavelength range - 1 mm to 700 nm
Detection - Infrared photographic film
Infrared wireless communication
Classification of EM Waves
Application of Infrared rays
Infrared lamps are used in physical therapy.
Classification of EM Waves
Application of Infrared rays
Infrared lamps are used in physical therapy.
Infrared rays maintain the earth’s temperature.
Classification of EM Waves
Application of Infrared rays
Infrared lamps are used in physical therapy.
Infrared rays maintain the earth’s temperature.
Infrared detectors are used in earth satellites, both for military purpose and to observe the growth of crops.
Classification of EM Waves
Application of Infrared rays
Infrared lamps are used in physical therapy.
Infrared rays maintain the earth’s temperature.
Infrared detectors are used in earth satellites, both for military purpose and to observe the growth of crops.
Electronic devices also emit infrared rays and widely used in the remote switches of household electronic systems such as TV sets, video recorders, and wi-fi systems.
Classification of EM Waves
4. Visible light
Classification of EM Waves
4. Visible light
Production - Electrons in atoms emit light when they move from higher energy level to lower energy level.
Spectrum of visible light
Classification of EM Waves
4. Visible light
Production - Electrons in atoms emit light when they move from higher energy level to lower energy level.
Wavelength range- 400 nm to 700 nm
Classification of EM Waves
4. Visible light
Production - Electrons in atoms emit light when they move from higher energy level to lower energy level.
Wavelength range- 400 nm to 700 nm
Detection - Eye photocells, photographic film
Classification of EM Waves
Colour | Wavelength (nm) |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Blue | 450 - 500 |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Blue | 450 - 500 |
Green | 500 - 550 |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Blue | 450 - 500 |
Green | 500 - 550 |
Yellow | 550 - 600 |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Blue | 450 - 500 |
Green | 500 - 550 |
Yellow | 550 - 600 |
Orange | 600 - 650 |
Classification of EM Waves
Colour | Wavelength (nm) |
Violet | 400 - 450 |
Blue | 450 - 500 |
Green | 500 - 550 |
Yellow | 550 - 600 |
Orange | 600 - 650 |
Red | 650 - 700 |
Classification of EM Waves
Application of visible light
Visible light emitted or reflected from objects around us provides us information about the world.
Classification of EM Waves
5. Ultraviolet rays
Classification of EM Waves
5. Ultraviolet rays
Production -The sun is an important source of UV Rays.
Inner shell electrons in atoms moving from one energy level to lower energy level.
UV rays generation
Classification of EM Waves
5. Ultraviolet rays
Production -The sun is an important source of UV Rays.
Inner shell electrons in atoms moving from one energy level to lower energy level.
Wavelength range- 400 nm to 1 nm
Classification of EM Waves
5. Ultraviolet rays
Production -The sun is an important source of UV Rays.
Inner shell electrons in atoms moving from one energy level to lower energy level.
Wavelength range- 400 nm to 1 nm
Detection - Photocells, photographic films
Classification of EM Waves
Application of Ultraviolet rays
UV lamps are used to kill germs in water purifiers.
Classification of EM Waves
Application of Ultraviolet rays
UV radiations can be focused into very narrow beams for high precision applications such as LASIK eye surgery.
Classification of EM Waves
Application of Ultraviolet rays
Ozone layer in the atmosphere absorbs UV rays coming from sun.
Classification of EM Waves
6. X-rays
Classification of EM Waves
6. X-rays
Production- X-rays tube or inner shell electrons
X-rays generation
Classification of EM Waves
6. X-rays
Production- X-rays tube or inner shell electrons
Wavelength range - 1 nm to 10 -3 nm
Classification of EM Waves
6. X-rays
Production- X-rays tube or inner shell electrons
Wavelength range - 1 nm to 10 -3 nm
Detection - photographic film, Geiger tubes, Ionisation chamber
Classification of EM Waves
Application of X-rays
X-rays are used as a diagnostic tool in medicine.
X-rays of body
Classification of EM Waves
Application of X-rays
X-rays are also used in treatment of certain form of cancer. X-rays damage or destroy living tissues and organism.
Destroying living tissues by using X rays
Classification of EM Waves
Application of X-rays
X-rays are used in luggage scanner at airport, railway station etc.
Luggage scanner
Classification of EM Waves
7. Gamma rays
Classification of EM Waves
7. Gamma rays
Production - Radioactive decay of nucleus
Classification of EM Waves
7. Gamma rays
Production - Radioactive decay of nucleus
Wavelength range - less than 10 -3 nm
Classification of EM Waves
7. Gamma rays
Production - Radioactive decay of nucleus
Wavelength range - less than 10 -3 nm
Detection - detected by observing
Classification of EM Waves
Application of Gamma rays
They are used in medicine to destroy cancer cells.
Classification of EM Waves
Application of Gamma rays
They are used in medicine to destroy cancer cells.
They are used to treat malignant tumours in radiotherapy.
Memory based question
Ready for challenge
Q. What type of waves are used to transmit cellular telephone messages?
Q. What type of waves are used to transmit cellular telephone messages?
Pause video
(Time duration : 2 minutes)
Q. What type of waves are used to transmit cellular telephone messages?
Sol.
Memory based question
Ready for challenge
Q. Which of the following is correct in order of lowest to highest frequency?
Q. Which of the following is correct in order of lowest to highest frequency?
Pause video
(Time duration : 2 minutes)
Q. Which of the following is correct in order of lowest to highest frequency?
Sol.
Memory based question
Ready for challenge
Q. Why are radio waves used extensively for communication?
Q. Why are radio waves used extensively for communication?
Pause video
(Time duration : 2 minutes)
Q. Why are radio waves used extensively for communication?
Sol.
Memory based question
Ready for challenge
Q. The energy of the EM Waves is of the order of 15 kev. Which part of the spectrum does it belong
Q. The energy of the EM Waves is of the order of 15 kev. Which part of the spectrum does it belong
Pause video
(Time duration : 2 minutes)
Q. The energy of the EM Waves is of the order of 15 kev. Which part of the spectrum does it belong
Sol.
Memory based question
Ready for challenge
Q. The condition under which a microwave oven heats up food containing water molecules most efficiently is
Q. The condition under which a microwave oven heats up food containing water molecules most efficiently is
Pause video
(Time duration : 2 minutes)
Q. The condition under which a microwave oven heats up food containing water molecules most efficiently is
Sol.
Memory based question
Ready for challenge
Q. The decreasing order of wavelength of infrared, microwave, ultraviolet rays and Gamma rays is
Q. The decreasing order of wavelength of infrared, microwave, ultraviolet rays and Gamma rays is
Pause video
(Time duration : 2 minutes)
Q. The decreasing order of wavelength of infrared, microwave, ultraviolet rays and Gamma rays is
Sol.
(d) Microwaves, Infrared rays, Ultraviolet rays, Gamma rays
Summary