Here are the detailed Electromagnetic Waves Class 12 Notes Chapter 8. Thus the notes will be very helpful in preparation for examinations. Class 12 Physics notes cover all the important topics that are listed. It gives students a basic understanding of the past and the development of laws in physics. https://meritbatch.com/electromagnetic-waves-cbse-notes-class-12-physics/
Electromagnetic Waves Class 12 Notes Chapter 8
Electromagnetic Waves Class 12 Notes
1. Displacement Current The current which comes into play m the region in which the electric field and the electric flux is changing with time. It is given by
Electromagnetic Waves Class 12
2. Need for Displacement Current Ampere’s circuital law for conduction current during charging of a capacitor was found inconsistent. Therefore, Maxwell modified Ampere’s circuital law.
3. The displacement current produces in space due to change of electric flux linked with the surface. This reveals that, varying electric field is the source of magnetic field.
Electromagnetic Waves Notes
4. Maxwell’s Equations of Electromagnetic Waves Maxwell’s equations are the basic laws of electricity and magnetism. These equations give complete description of ail electromagnetic interactions.
There are four Maxwell’s equations which are explained below:
Em Waves Class 12 Notes
5. Electromagnetic Waves An electromagnetic wave is a wave radiated by an accelerated or oscillatory charge in which varying magnetic field is the source of electric field and varying electric field is the source of magnetic field. Thus two fields becomes source of each other and the wave propagates in a direction perpendicular to both the fields.
Em Waves Class 12
6. Electromagnetic waves are transverse in nature, i.e. electric and magnetic fields are perpendicular to each other and to the direction of wave propagation. Electromagnetic waves are not. deflected by electric and magnetic fields.
7. E (electric field) and B (magnetic field) in electromagnetic waves are in same phase.
Class 12 Physics Chapter 8 Notes
8. Speed of electromagnetic wave
9. The energy in electromagnetic wave is divided on average equally between electric and magnetic fields.
Em Waves Notes
11. Linear momentum delivered to the surface, p= U/c
where, U = total energy transmitted by electromagnetic waves and c = speed of electromagnetic wave.
Class 12 Electromagnetic Waves Notes
12. Electromagnetic Spectrum The systematic sequential distribution of electromagnetic waves in ascending or descending order of frequency or wavelength is known as electromagnetic spectrum. The range varies from 10-12 m, to 104 m, i.e. from γ-rays to radio waves.
13. Elementary facts about the uses of electromagnetic waves
Radio waves
(i) In radio and TV communication.
(ii) In astronomical field.
Microwaves
(i) In RADAR communication.
(ii) In analysis of molecular and atomic structure.
(iii) For cooking purpose.
Class 12 Physics Electromagnetic Waves Notes
Infrared waves
(i) In knowing molecular structure. (ii) In remote control of TV VCR, etc.
Ultraviolet rays
(i) Used in burglar alarm. (ii ) To kill germs in minerals.
X-rays
(i) In medical diagnosis as they pass through the muscles not through the bones.
(ii) In detecting faults, cracks, etc., in metal products,
γ-rays
(i) As food preservation. (ii) In radiotherapy.
Electromagnetic Waves Notes Class 12
14. The optical effect is produced by electric field vector of the electromagnetic waves.
