Blackbody Radiation Part 1 - Experimental Observations: Stefan Law, Wiens Displacement Law

[@FortheLoveofPhysics]

1. Blackbody Observations - kzbin.info/www/bejne/fIPHY2t5gduAh68 2. Rayleigh Jeans Law - kzbin.info/www/bejne/oXndZ62YedacnLM 3. Planck Energy Distribution - kzbin.info/www/bejne/qnK9in6EgNCrqZY 4. Summary - kzbin.info/www/bejne/gYObhKCQast6f8k

[@muthiahpillaipalanichamy3939]

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

[@EnochBrown-s5j]

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.

[@jasnoor8-d-155]

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

[@TheodorerooseveltTheFourTH]

@@jasnoor8-d-155 im here for the same reason

[@saveearth9816]

... 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

[@tesukim4338]

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.

[@JJGhostHunters]

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!

[@MrBlazy-bc8vz]

Best lecture of physics till now I have seen👏👏👏

[@ajaykumar-tq9sq]

Your teaching method is incredible. Thank you so much.

[@abrahamdanan6893]

I command you for the clarity of your explanations which don’t neglect any details. Thanks

[@aarontseke1918]

Why I love your teaching is that, you always found a way to explain on ease

[@classroomgurumaths]

Great teacher! I love your lectures so much. Please continue with this. Thank you.

[@bpperbpper7750]

This is brilliant. I'm so hungry for more lectures. Thank you very much for your effort!

[@samraawan841]

great lecture. But I'm confused is it Lambda minimum or lambda maximum associated with neu maximum in your derivation. Please help

[@rohankanu9880]

Yeah it's lemda minimum

[@wahydgold]

@@rohankanu9880 because wavelength and frequency are inversely related.

[@KJ93STUDIO]

I am studying Applied Physics from Halidey Resnick book, Chapter 45. Your video was very helpful . Thank you for such a great explanation.

[@Sakib.Shahriar]

Been trying to learn this since a long time. Thanks.

[@prabhnoorjagdav8728]

I hope me 2 bay boo

[@khushbusahani9101]

Sir ,The way of teaching is really appreciable thanks a lot. Love from Nepal.

[@eternalthoughts-wu5lo]

this is a brilliant lecture...I like it and I strongly recommand every student of physics to watch it

[@6StringDuck]

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!

[@eaula8696]

I can see the love on physics from teacher's eye. thank you so much. big love from seoul

[@amarmail8033]

Superb. Now I understand why its called black body radiation and why its necessary to have a black body. Superb as always.

[@me0wAnna]

Your videos are brilliant sir. Such rich content

[@ShivaniSingh-xf5ok]

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 😊

[@ankushabhat1599]

Wonderful lecture sir. One of the best thing I heard so far. Thank You

[@comedyandmovie-dp3pr]

I have no words to appreciate you,your explanation are so easy😊😊

[@sneakyboi2671]

Brilliant!!! Also congratulations for hitting 100 thousand subscribers!!!

[@cesarmoreno987y]

You are a great explainer! Love watching your lectures

[@cesarmoreno987y]

You are my favorite physics explainer

[@appannasidagam8564]

How amazing the class is. It is so wonderful and like a ride in a roller coaster

[@jayanalawaade2041]

Very precise and impressive lecture .... thoroughly understand black body radiation.

[@NimraSaleem-ec4uy]

Ye kitna awesome he yar!! I have an exam and i was literally struggling to understand the concepts, thankyou sir.

[@seekingrafael5630]

VERY HIGH QUALITY TUTORIAL. THANK YOU!! :)

[@munamallik3986]

Great lecture Sir, I am always waiting, when will your video come , very much Happy to see you

[@bilalphysics4872]

Your knowledge most important the way you represent has no match Sir ❤

[@PriyanshuNigam-vu1po]

Sir is really really underrated

[@Dipayan21485]

Thank you so much sir for this amazing lecture

[@anirbanOprasenjit]

Outstanding teaching..kudos..

[@priyankalochab7574]

Brilliant lecture.. got to learn many things ☺️👍

[@ronitkumar4619]

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

[@wahydgold]

You're a great teacher

[@sakhiali4751]

Thanks sir i love the way you teach sir

[@ganeshramamurthi9663]

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 ..."

[@AMANKUMAR-ww9us]

congratulation sir for 100k subscribers.

[@fastestslowest1864]

A very great video sir... Love from the Hansraj College...

[@jamesraymond1158]

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.

[@Kneegrowww_911]

Dibyajyoti Das...found it in the description

[@wafakhan8251]

You are amazing teacher

[@swapnilgupta2112]

loved the lecture!

[@Rainbowcolours09]

Nice Session Sir...just wondering your classes 🎉...and now becouse of u l came to know the basics...😂

[@kainturaji3689]

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.

[@MIP514]

Great Teacher❤

[@BerhanuReda-vq9oe]

happy to see your video thank you

[@salrimemsangma3854]

Thank you sir Your explanation is great

[@suneecat]

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.

[@OjaswiRai-s7x]

thank you sir

[@chemistryguds]

Sir u r on the way to became known personality in physics.

[@MohammadAlshahrani]

You did it very well, good explanation

[@drbitanmaity]

Brilliant lecture….

[@redwan711]

great lecture ❤❤❤

[@socrat12]

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/

[@harry-ho9ti]

Kindly upload at least two lecture in a week

[@sailokeshclassroom4044]

Nice lecture sir, Nice English

[@VishalKumar-ro4vs]

great lecture

[@achalumrigar]

Thank you very much sir❤

[@ekta-jangra]

Very nice explanation Sir 👏 Thanku Sir😊

[@vaibhavshreyakar5991]

What an explanation!!!!!!!! ☺🙏

[@sushmamishra9268]

Next lecture please 🙏

[@thusithawickramanayaka4493]

Dear Sir, Can we have the remaining topics in QM also ....? Thanks for your superb series of lectures..

[@muthuseethalakshmi525]

Thankyou for this video sir

[@lifetheories2452]

Thank you so much sir 💗

[@annadisanjeevareddy9538]

Superb sir

[@cantantephoto8696]

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.

[@AnjalPandey-mg8hd]

I really appreciate with your skill , thank you so much sirr ,

[@subratasikdar4997]

Your explanation is sir so sweet, ❤❤❤

[@Theories_stuff]

It's extraordinary!

[@Awakeknowledge]

i like much sir your english communications skills.

[@aakashvideo]

Thank you for the video.

[@vipinpnair]

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.

[@mysterious5678]

I think it's only about Blackbody. Hence, sir didn't include emissivity.

[@abhijitchatterjee3129]

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.

[@anandchaurasiya2668]

Sir need lecture on polarization of light such as circular ,eliptical ....

[@alishair6444]

Sir please upload video as soon as possible we are eagerly waiting for you heart touching videos 😢😢😢

[@motif123456]

It would be nice if you could derive plank's spectral irradiance formula in your subsequent video

[@FortheLoveofPhysics]

Will do

[@impresent2005]

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????

[@gok_dogan]

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 ?

[@suneecat]

Of course, both are possible. The question is, under what conditions is each behaviour likely to occur.

[@saranshkala335]

sir but spectral energy density to energy per unit vol per unit frequency/wavelength hoti haina?

[@sksaini7461]

Thank you sir

[@fractalnomics]

Snow and white paint have similar emissivities of near 0.9. Does this make them near blackbodies?

[@samiranguchhait350]

thank you sir💓💓💓

[@mrslave41]

13:14 Can you explain how this graph was obtained?

[@FortheLoveofPhysics]

It's an experimental observation, of radiation Power (for a fixed frequency width) v/s frequency

[@alkasoni4688]

Sir i have query only why black body choosed for the experiment .why only thermal radiations.

[@Caravanseraii]

thank you

[@ayushjha8075]

love from Btech 1st year IIT Kanpur...

[@harry-ho9ti]

Excellent explanation as compared to others❤. Hope ur health is OK sir.

[@FortheLoveofPhysics]

I am fine now. Thanks :)

[@dr.saurabhkunj5423]

@@FortheLoveofPhysics Good to listen that

[@sanjanayadav9765]

Sir why we use metal while designing black body

[@MadhubhashiniDasanayake]

Thankuu sir😊

[@abdurrauf7525]

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.

[@ajithg796]

❤ excellent, excellent, excellent.... 🎉

[@sanjanayadav9765]

Sir the graph of spectral density versus frequency graph not start from origin why you draw it from origin?

[@divyakumar8147]

thanks

[@homemobile8362]

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 ?

[@FortheLoveofPhysics]

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

[@homemobile8362]

Okay thank u sir❤❤❤

[@malavikap7433]

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.

[@rajveertaneja161]

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

[@FortheLoveofPhysics]

I wrote in terms of wavelength/frequency corresponding to maximum-power in that spectrum

[@rajveertaneja161]

@@FortheLoveofPhysics yes but that's what I am saying when frequency is maximum wavelength is minimum

[@FortheLoveofPhysics]

@@rajveertaneja161 it's NOT "maximum Frequency". Its a particular frequency at which POWER of the spectrum has a maxima

[@pritambiswas4810]

Sir the graph I thought you draw wrong as for higher temperatures the maximum emissive power shift to lower frequency

[@FortheLoveofPhysics]

No. It shifts to higher frequency and lower wavelength.

[@hellYeahh]

Thank you sir for your service. You are just like a photon which can charge a "dead atom" in me. (Of course Atoms don't die)

[@prestigious786]

It is wrong to say that body contains heat! Bodies don't contain heat. They contain internal energy. Heat is energy that is transferred owing to the temperature difference