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Introduction and Uses of EM Waves (in Hindi)
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Origins of EM wave and role of Maxwell in discovering the same

Udit Gupta is teaching live on Unacademy Plus

Udit Gupta
Star Educator in Physics + Teacher + Counsellor + Hedonist Now on Unacademy Plus as well!

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Thankyou So Much Guru ji
sir time varying electric field time varying magnetic field produce karti hai kya
Udit Gupta
4 months ago
yes exactly that is whati have tried to explain
Sir plz solve this ,orange comes after 550 nm and before 700nm but I dont understand y the answer is option (B), plz explain... Q- A carrot looks orange in colour because of the β carotene molecule in it. This means that the β carotene molecule absorbs light of wavelengths A) longer than 550 nm. B) shorter than 550 nm. C) longer than 700 nm. D) shorter than 700 nm.
Udit Gupta
7 months ago
see we have wavelength of visible light from 400 to 700nm. now Yellow is considered mean (remember it as a fact). So yellow has 550 (mean). Orange has gotta be between 550 and 700. So the option that matches here should be A and D. Actual wavelength of orange is somewhere between 590 to 635nm.
Sir meine bhi yehi socha tha par answer unhone ( B) diya hai...
Udit Gupta
7 months ago
galat hai answer itna tension mat lo
ok sir😅
but vo kvpy mei poocha gya tha and ans key mei bhi( B ) tha so I was confused
Udit Gupta
7 months ago
ek bar google karlo wavelength of orange. Dikhaave pe mat jao, apni akal lagao! clear hai..
ok sir 590-635nm hai ha sir clear hai
Pratik Gupta
6 months ago
Koi bhi substance jo wavelength ka colour ka colour emit karta h. Uske complement colour ka wavelength absorb krta h. Orange ka wavelength mean (550) se jyada h. To absorbed colour ka wavelength mean (550) se kam hoga. So, I guess B sahi option h.
Hmm ho sakte hai means agar koi x substance 430 se zyada emit karti hai to vo absorb 430 se kam karegi?
Pratik Gupta
6 months ago
agr colour emitted ka wavelength mean se kam h. To colour absorbed ka wavelength mean se jyada hoga. Matlab mean ke complement hoga
Pratik Gupta
6 months ago
550 se jyada emit kar raha h to 550 se kam absorb karega
ok understood😄
Aap 12th class mei padte ho?
Pratik Gupta
5 months ago
12th passed
oh ok😁
Pratik Gupta
5 months ago
:)
Gagandeep Singh
5 months ago
It is orange because it absorbs blue light. so answer is B
Gagandeep Singh
5 months ago
It is orange because it absorbs blue light. so answer is B
ok
sir when we accelerate or oscillate a charge an emw is produced, but in the very begining of wave production charge will have conservative electric field, so does varying conservative electric field produce varying magnetic field
Udit Gupta
5 months ago
Electric field and magnetic field exist in a couple. Either both will be there or none. As far as a stationary charge is taken into consideration it is an idealised scenario, so both E and B must exist simultaneously always.
thamku sir really helpful ...and awesome vedio
Happy teachers day sir I am very happy to miss you
Udit Gupta
9 months ago
sure thanks or not?
  1. Electromagnetic waves Introduction


  2. Greetings! I am your educator - Udit Gupta. In the first lesson of this course, we shall discuss the importance and discovering these waves. For more learning, follow the link below: utiiies of EM waves, les orngin and the role of James Clerk Maxwell in https://unacademy.com/user/udit13


  3. Introduction What is light? This question has been asked by humans for centuries, but there was no answer until electricity and magnetism were unified into electromagnetism, as described by Maxwell's equations. These equations show that a time-varying magnetic field acts as a source of electric field and that a time- varying electric field acts as a source of magnetic field These and fields can sustain each other, forming an electromagnetic wave that propagates through space


  4. Introduction Visible light emitted by the glowing filament of a light bulb is one example of an electromagnetic wave; other kinds of electromagnetic waves are produced by TV and radio stations, X-ray machines, and radioactive nuclei. . In this course we'll use Maxwell's equations as the theoretical basis for understanding electromagnetic waves. We'll find that these waves carry both energy and momentum. . In sinusoidal electromagnetic waves, the electric and magnetic fields are sinusoidal functions of time and position, with a definite frequency and wavelength. 4


  5. Introduction . Visible light, radio, x rays, and other types of electromagnetic . Unlike waves on a string or sound waves in a fluid, waves differ only in their frequency and wavelength electromagnetic waves do not require a material medium; the light that you see coming from the stars at night has travelled without difficulty across tens or hundreds of light-years of (nearly) empty space. . Nonetheless, electromagnetic waves and mechanical waves have much in common and are described in much the same language 5


  6. Maxwell's Equation and EM Waves . In the last several courses we studied various aspects of electric and . We learned that when the fields don't vary with time, such as an electri magnetic fields. field produced by charges at rest or the magnetic field of a steady current, alyse t he electric and magnetic fields independently without onsidering interactions between thenm But when the fields vary with time, they are no longer independent. Faraday's law tells us that a time-varying magnetic field acts as a source of electric field, as shown by induced emfs in inductors and transformers. . 6


  7. Maxwell's equation and EM waves Ampere's law, including the displacement current discovered by Maxwell, shows that a time-varying electric field acts as a source of magnetic field. This mutual interaction between the two fields is summarized in Maxwell's equations. Thus, when either an electric or a magnetic field is changing with time, a field of the other kind is induced in adjacent regions of space We are led (as Maxwell was) to consider the possibility of an electromagnetioc disturbance, consisting of time-varying electric and magnetic fields, that can propagate through space from one region to another, even when there is no matter in the intervening region. Such a disturbance, if it exists, will have the properties of a wave, and an appropriate term is electromagnetic wave. . . . 7


  8. THANKS FOR WATCHING! If you think this was genuine stuff and could benefit others, do not forget to rate & review this course. Doubts and queries are welcome Comment or leave a message to get it sorted. For more such courses, visit: https://unacademy.com/user/udit13


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