You are better than all other teachers around the world, I believe. I am a 72 years old teacher, but I am getting inspiration from you. Be proud of you
I would tell anyone who wants to study thermodynamics that they watch your lectures first. You presentation is just brilliant!!! For instance, I did not even think about why physicists thought of using a hollow sphere. Your insight that a flat surface would reflect some of the radiation which then would not be able to be recaptured is a great one! I watched countless videos on this very subject and was never satisfied.
Indeed its a fantastic video , i am preparing for iit jee and was really confused about blackbody radiation , after wasting an hour on videos and books i came across this and all my concepts got cleared
... I had watched many videos about this phenomenon (BLACK BODY RADIATION) what was confusing me is how they construct the curve for each certain temperature.... Then I understand that they heat the matter for e. g to 3000 K the body will glow (emit visible light +IR&UV ray) then they will pass this light through glassy prism which will analyse it into the spectrum including visible colors +IR&UV... Then they measure the intensity of each part of the spectrum (starting from IR...then visible light colors ended by UV) Plot wave length (horizontal) & intensity longitudinal
His lecture is great. I’m a Korean but his lecture is much better than Korean lectures that I have watched. Outstanding expertise, super well organized, and in the end I could understand the subject much better. The invaluable channel for me.
Not only are they great content wise...the writing and drawing on the chalkboard is absolutely beautiful! You can tell he takes pride in communicating the concepts as clear as possible without messy equations!
The graph relating to the ultraviolet catastrophe has had me confused for ages, I couldn't figure out why it went from UV into Infrared. Now it all makes sense. Well as much to me the layman. Thank you!
At 17:43 you say "... for another body ... ". What you really mean to say is "... for another temperature ...". That would be more clear. But nonetheless, a great lecture. Very informative and very well done. Thank you.
With due respect to your expertise, I may like to point out that as per Thermodynamics " Heat is not contained in a body, it is internal energy that resides inside a system. Heat is energy identified in boundary only during its transit ..."
Wonderful sir ❤️ Sir one request can you please make it one video at a week so our learning will be more disciplined and quite regular. I know you have to manage other things as well but if possible please consider this also.
The speaker (I can't find his name) must have had wonderful teachers. He speaks very well, has excellent handwriting, and can draw lines and circles with great skill.
Spectral Energy Density - Amount of energy per unit time per unit surface area that is being emitted by the black body cavity for a given range of frequency of an EM
sir, I have a doubt...... sir as Vmax is directly proportional to temp. and when we do c/lambda.....so, lambda must be minimum but apne maximum likha hai????
Why do they need the internally reflecting sphere with the tiny hole, as opposed to just something black. I guess maybe a black object absorbs all the visible rays but not necessarily the infrared and ultraviolet?
Your answer to the following please: Suppose there is a cave where we can't see anything inside. There is an opening of the cave, and from outside if we look through, nothing can be seen. Because it can act as a black body. Now, can I interpret like, some may be seen within, in summer rather than winter. Because, in summer, the temp of the cave ( black body) remains high enough and hence the emitted thermal radiation would be more and of higher energy and may fall in the visible region.
Professor I wonder that Can a free electron (in vacuum) absorb photon ? Likewise is it possible for an electron (it isn't in an orbit of an atom ) to emit photon ?
21.40 “if a charged particle like an electron is vibrating (due to higher energy/heat) then it emits an electromagnetic wave” Sounds obvious if the penny has dropped. Why hasn’t any book I’ve read explained it so simply before? Thank You.
I see emissivity factor is also considered for thermal calculations. But this is missing here in these lecture series . Please include a reason why emissivity changes with material, even though black body radiation is independent of material.
12:14 ;I have small doubt on x axis of this graph sir ,i saw many graphs labeled it as wavelength 🤔not frequency, why is it? Wavelength is inversely proportional to frequency ?
Yes, wavelength and frequency are inversely proportional. If you go through the literature, you vl find many books with frequency on the x axis and many others with wavelength. Both are OK. I chose frequency, as in later lectures my calculations will be very much based on frequency
About the quantum of light 1- In the 19th century, much attention was paid to the study of the thermal properties of various objects. The idealized model that was considered was the Black Body. (Max von Laue called the black body the “Kirchhoff vacuum.” It was also called the “ultraviolet catastrophe”; the first signs of the “vacuum catastrophe”) 2- In 1900, Max Planck solved the “black body” problem by discovering the “quantum of action of light - h”. Particle (h) is not a hot particle emitted by stars. Particle (h) came from the vacuum, from the cosmic vacuum. 3- Einstein's second postulate states: In a vacuum, light propagates at a constant speed (c), which does not depend on the speed and radiation of the source or observer. 4. According to SRT, a quantum of light is not a solid particle. 5- According to quantum physics, a quantum of light has its own internal “spin” (linear or angular). 6- Light is an independent and free quantum particle. Its movement does not depend on the speed of the source or the observer. The actions of light do not depend on the opinions of physicists. # "All these fifty years of conscious brooding have brought me no nearer to the answer to the question "What are light quanta?". Nowadays every Tom, Dick, and Harry thinks he knows it, but he is mistaken." /Albert Einstein/
Sir, I also wonder whether there were experimental observations and scientists were trying to explain the spectrum. Or theory and experiment were going side by side to derive a function proposed by Gustav Kirchhoff (the radiation emitted from a black body within a given wavelength interval is a universal function depending only on the temperature of the body) about black body radiation.
Sir, I have a doubt. If the blue chalk is absorbing all the other wavelengths what is happening to the electrons of the atoms of the chalk that are absorbing all the incident light? That incident light is probably not enough to excite the electrons into their higher states. Please explain. Thanks.
sir, when you were deriving the wien's displacement law you wrote (lemda)max corresponding to max frequency but don't you think it should be (lemda) min as when frequency is max wavelength is min
1. Blackbody Observations - th-cam.com/video/FRd28CLvMQM/w-d-xo.html
2. Rayleigh Jeans Law - th-cam.com/video/kHz6zbDqifQ/w-d-xo.html
3. Planck Energy Distribution - th-cam.com/video/tAZYKNKkxs4/w-d-xo.html
4. Summary - th-cam.com/video/KR8SmZ5fGIg/w-d-xo.html
You are better than all other teachers around the world, I believe. I am a 72 years old teacher, but I am getting inspiration from you. Be proud of you
I would tell anyone who wants to study thermodynamics that they watch your lectures first. You presentation is just brilliant!!! For instance, I did not even think about why physicists thought of using a hollow sphere. Your insight that a flat surface would reflect some of the radiation which then would not be able to be recaptured is a great one! I watched countless videos on this very subject and was never satisfied.
Indeed its a fantastic video , i am preparing for iit jee and was really confused about blackbody radiation , after wasting an hour on videos and books i came across this and all my concepts got cleared
@@jasnoor8-d-155 im here for the same reason
... I had watched many videos about this phenomenon (BLACK BODY RADIATION)
what was confusing me is how they construct the curve for each certain temperature.... Then I understand that they heat the matter for e. g to 3000 K the body will glow (emit visible light +IR&UV ray) then they will pass this light through glassy prism which will analyse it into the spectrum including visible colors +IR&UV... Then they measure the intensity of each part of the spectrum (starting from IR...then visible light colors ended by UV)
Plot wave length (horizontal) & intensity longitudinal
His lecture is great. I’m a Korean but his lecture is much better than Korean lectures that I have watched. Outstanding expertise, super well organized, and in the end I could understand the subject much better. The invaluable channel for me.
Not only are they great content wise...the writing and drawing on the chalkboard is absolutely beautiful! You can tell he takes pride in communicating the concepts as clear as possible without messy equations!
You are right , could u share Whatsapp number with me
Best lecture of physics till now I have seen👏👏👏
I command you for the clarity of your explanations which don’t neglect any details. Thanks
Your teaching method is incredible. Thank you so much.
This is brilliant. I'm so hungry for more lectures. Thank you very much for your effort!
great lecture. But I'm confused is it Lambda minimum or lambda maximum associated with neu maximum in your derivation.
Please help
Yeah it's lemda minimum
@@rohankanu9880 because wavelength and frequency are inversely related.
Your English is fantastic, reflecting Calcutta’s great ICSE schools, enunciation too is very well done, no swallowing of words or alphabets. Good job!
Why I love your teaching is that, you always found a way to explain on ease
I am studying Applied Physics from Halidey Resnick book, Chapter 45. Your video was very helpful . Thank you for such a great explanation.
Been trying to learn this since a long time. Thanks.
I hope me 2 bay boo
Great teacher! I love your lectures so much. Please continue with this. Thank you.
Sir ,The way of teaching is really appreciable thanks a lot.
Love from Nepal.
this is a brilliant lecture...I like it and
I strongly recommand every student of physics to watch it
As the name of channel for the love of physics sir you really an amazing teacher who make sure that we all fall in love with physics 😊
I can see the love on physics from teacher's eye. thank you so much. big love from seoul
The graph relating to the ultraviolet catastrophe has had me confused for ages, I couldn't figure out why it went from UV into Infrared. Now it all makes sense. Well as much to me the layman. Thank you!
Wonderful lecture sir. One of the best thing I heard so far. Thank You
Superb. Now I understand why its called black body radiation and why its necessary to have a black body. Superb as always.
Brilliant!!! Also congratulations for hitting 100 thousand subscribers!!!
I have no words to appreciate you,your explanation are so easy😊😊
You are a great explainer! Love watching your lectures
My background is masters in bio but suddenly I found interest in quantum mechanics...so I am here enjoying your lectures
Your videos are brilliant sir.
Such rich content
How amazing the class is. It is so wonderful and like a ride in a roller coaster
Ye kitna awesome he yar!! I have an exam and i was literally struggling to understand the concepts, thankyou sir.
Your knowledge most important the way you represent has no match
Sir ❤
Great lecture Sir, I am always waiting, when will your video come , very much Happy to see you
You are my favorite physics explainer
Thank you so much sir for this amazing lecture
Very precise and impressive lecture .... thoroughly understand black body radiation.
Brilliant lecture.. got to learn many things ☺️👍
Sir is really really underrated
Nice Session Sir...just wondering your classes 🎉...and now becouse of u l came to know the basics...😂
At 17:43 you say "... for another body ... ". What you really mean to say is "... for another temperature ...". That would be more clear.
But nonetheless, a great lecture. Very informative and very well done. Thank you.
VERY HIGH QUALITY TUTORIAL. THANK YOU!! :)
With due respect to your expertise, I may like to point out that as per Thermodynamics " Heat is not contained in a body, it is internal energy that resides inside a system. Heat is energy identified in boundary only during its transit ..."
Wonderful sir ❤️
Sir one request can you please make it one video at a week so our learning will be more disciplined and quite regular. I know you have to manage other things as well but if possible please consider this also.
Kindly upload at least two lecture in a week
happy to see your video
thank you
Outstanding teaching..kudos..
The speaker (I can't find his name) must have had wonderful teachers. He speaks very well, has excellent handwriting, and can draw lines and circles with great skill.
Dibyajyoti Das...found it in the description
Thanks sir i love the way you teach sir
Spectral Energy Density - Amount of energy per unit time per unit surface area that is being emitted by the black body cavity for a given range of frequency of an EM
congratulation sir for 100k subscribers.
Great Teacher❤
You're a great teacher
A very great video sir... Love from the Hansraj College...
sir, I have a doubt......
sir as Vmax is directly proportional to temp. and when we do c/lambda.....so, lambda must be minimum but apne maximum likha hai????
Sir u r on the way to became known personality in physics.
13:14 Can you explain how this graph was obtained?
It's an experimental observation, of radiation Power (for a fixed frequency width) v/s frequency
Why do they need the internally reflecting sphere with the tiny hole, as opposed to just something black. I guess maybe a black object absorbs all the visible rays but not necessarily the infrared and ultraviolet?
great lecture ❤❤❤
You did it very well, good explanation
What an explanation!!!!!!!!
☺🙏
Dear Sir,
Can we have the remaining topics in QM also ....? Thanks for your superb series of lectures..
Thank you sir
Your explanation is great
Very nice explanation Sir 👏
Thanku Sir😊
You are amazing teacher
Next lecture please 🙏
Your answer to the following please:
Suppose there is a cave where we can't see anything inside. There is an opening of the cave, and from outside if we look through, nothing can be seen. Because it can act as a black body. Now, can I interpret like, some may be seen within, in summer rather than winter. Because, in summer, the temp of the cave ( black body) remains high enough and hence the emitted thermal radiation would be more and of higher energy and may fall in the visible region.
Sir why we use metal while designing black body
Professor
I wonder that
Can a free electron (in vacuum) absorb photon ?
Likewise
is it possible for an electron (it isn't in an orbit of an atom ) to emit photon ?
Of course, both are possible. The question is, under what conditions is each behaviour likely to occur.
sir but spectral energy density to energy per unit vol per unit frequency/wavelength hoti haina?
21.40 “if a charged particle like an electron is vibrating (due to higher energy/heat) then it emits an electromagnetic wave” Sounds obvious if the penny has dropped. Why hasn’t any book I’ve read explained it so simply before? Thank You.
I really appreciate with your skill , thank you so much sirr ,
Nice lecture sir,
Nice English
Sir need lecture on polarization of light such as circular ,eliptical ....
Thank you very much sir❤
I see emissivity factor is also considered for thermal calculations. But this is missing here in these lecture series . Please include a reason why emissivity changes with material, even though black body radiation is independent of material.
I think it's only about Blackbody. Hence, sir didn't include emissivity.
Sir i have query only why black body choosed for the experiment .why only thermal radiations.
Brilliant lecture….
Snow and white paint have similar emissivities of near 0.9. Does this make them near blackbodies?
Superb sir
Sir the graph of spectral density versus frequency graph not start from origin why you draw it from origin?
Your explanation is sir so sweet, ❤❤❤
thank you sir
12:14 ;I have small doubt on x axis of this graph sir ,i saw many graphs labeled it as wavelength 🤔not frequency, why is it? Wavelength is inversely proportional to frequency ?
Yes, wavelength and frequency are inversely proportional. If you go through the literature, you vl find many books with frequency on the x axis and many others with wavelength. Both are OK. I chose frequency, as in later lectures my calculations will be very much based on frequency
Okay thank u sir❤❤❤
About the quantum of light
1- In the 19th century, much attention was paid to the study of the thermal properties of various objects. The idealized model that was considered was the Black Body. (Max von Laue called the black body the “Kirchhoff vacuum.” It was also called the “ultraviolet catastrophe”; the first signs of the “vacuum catastrophe”)
2- In 1900, Max Planck solved the “black body” problem by discovering the “quantum of action of light - h”. Particle (h) is not a hot particle emitted by stars. Particle (h) came from the vacuum, from the cosmic vacuum.
3- Einstein's second postulate states: In a vacuum, light propagates at a constant speed (c), which does not depend on the speed and radiation of the source or observer.
4. According to SRT, a quantum of light is not a solid particle.
5- According to quantum physics, a quantum of light has its own internal “spin” (linear or angular).
6- Light is an independent and free quantum particle. Its movement does not depend on the speed of the source or the observer. The actions of light do not depend on the opinions of physicists.
#
"All these fifty years of conscious brooding have brought me no nearer to the answer to the question "What are light quanta?". Nowadays every Tom, Dick, and Harry thinks he knows it, but he is mistaken." /Albert Einstein/
Thank you so much sir 💗
great lecture
It would be nice if you could derive plank's spectral irradiance formula in your subsequent video
Will do
Sir the graph I thought you draw wrong as for higher temperatures the maximum emissive power shift to lower frequency
No. It shifts to higher frequency and lower wavelength.
Sir, I also wonder whether there were experimental observations and scientists were trying to explain the spectrum. Or theory and experiment were going side by side to derive a function proposed by Gustav Kirchhoff (the radiation emitted from a black body within a given wavelength interval is a universal function depending only on the temperature of the body) about black body radiation.
Sir, I have a doubt. If the blue chalk is absorbing all the other wavelengths what is happening to the electrons of the atoms of the chalk that are absorbing all the incident light? That incident light is probably not enough to excite the electrons into their higher states. Please explain. Thanks.
Sir please upload video as soon as possible we are eagerly waiting for you heart touching videos 😢😢😢
sir, when you were deriving the wien's displacement law you wrote (lemda)max corresponding to max frequency but don't you think it should be (lemda) min as when frequency is max wavelength is min
I wrote in terms of wavelength/frequency corresponding to maximum-power in that spectrum
@@FortheLoveofPhysics yes but that's what I am saying when frequency is maximum wavelength is minimum
@@rajveertaneja161 it's NOT "maximum Frequency". Its a particular frequency at which POWER of the spectrum has a maxima
Thankyou for this video sir
Very nice..... 🎉
Lambda max or lambda min ? at 18 min
i like much sir your english communications skills.
Sir where u have taken the lamda max there will be lamda min
lambda max corresponds to wavelength with max energy density
Sir why wavelength maximum with maximum frequency?
It's the wavelength at which spectral density is maximum
Thank you for the video.
i think in wiens displacement law not lamdla max it is lamdla min
It's extraordinary!
Sir if a perfect black body emits thermal radiation in visible spectrum range how can it be a black body to our eyes ...
It is just a misnomer it is not named as if it looks black but simply emits and absorbs all radiation that’s it .
Excellent explanation as compared to others❤. Hope ur health is OK sir.
I am fine now. Thanks :)
@@FortheLoveofPhysics Good to listen that
❤ excellent, excellent, excellent.... 🎉