If light energy was quantised in Photoelectric Effect, now it is colliding with electrons in the Compton Effect :) th-cam.com/video/oTNiJVdEyCc/w-d-xo.html
No one can understand quantum physics according to Feynman but we are lucky to have you. you have explained it in the best and easiest way possible. I haven't seen better way from this. Thankyou Sir... 💕💕❤️
Love that sigh towards the end, not a sigh of tiredness or disappointment, but rather of a job well done and maybe of some admiration towards Planck and Einstein. Your transition from classical to the quantum world in the last couple of lectures is brilliant. I enjoy Physics in layman’s term (a little Calculus and Diff Eqs is OK). I didn’t know about this sequence of events between Black Body Radiation, UV Catastrophe, Planck’s resolution and Einstein’s PEE. No more googling, you’re now my Master and I’m your Grasshopper.
excellant lecture...this professor is a brilliant teacher Bengali people are naturally brilliant and genius...most of them....some atel guys also exist
U are the type of teacher ..which makes student feel physics ..nd feel why are we studying physics ..u make it interesting..in every way possible..which very few teachers do..nd when u teach ..u give details bout every small thing in ur knowledge..which is truly appreciable..best teacher❤️
Sir I lack the best words to express not only your teaching methodology but also how you make Physics look simple and interesting. You explain the concept of Photoelectric Effect in a hilarious way, making it get perfectly absorbed in my brain. Thanks so much. I am subscribing to your channel. It can be wonderful to attend your live classes online incase you have an online teaching and discussion platform.
I first watched your video years ago but only just now that I finally get to video-hopping on your channel. I am hooked. Thank you, I hope you'll never stop.
How do you theoretically calculate the classical time delay (hours, days, etc. as you mentioned)? How do you theoretically calculate the quantum mechanical time delay (10^-9 sec as you mentioned)?
Thanks a lot sir, I have one question please, The cross section per atom depends upon approximately Z* for high atomic number materials and on Z4.8 for low Z materials. Since each atom contains Z electrons, the coefficient per electron depends upon Z³ and Z3.8 for high and low Z materials respectively. Since the number of elec- trons per gram is more or less independent of Z, we would expect the mass coefficients to vary as Z3 and Z3.8 for the two classes of materials. These statements are at best rough guides. That the variation of the mass coefficient depends roughly on Z³ can be seen from Figure 5-5. Above the K edge in lead, the coefficient is one thousand times as large as it is in water (slightly over 3 cycles on the vertical scale), while their atomic numbers of 82 and 7.5 are in the ratio of about 10:1. If you can explain it ,
This isn't an atomic process. The electrons that are absorbing the energy of the photon are in the conduction band of the metal, i.e. their binding energy is much lower than the ionization energy of the individual atoms will suggest. In practice we also have to consider the thermal excitation of the conduction band, so unless the metal is cooled, there will be a considerable amount of thermal "smearing" of the work function.
I understand before the light is shone on the anode there is no current across the vacuum tube. Whilst the excited electrons might fly against the force of the electric field to the cathode, the momentum of their flight is not going to push them any further than the cathode; its not going to push them through the wire to the negative terminal of the battery (something else might though). I expect the arrival of the electrons at the cathode reduces the electric potential at the cathode (raises its negativity) compared to that at the negative terminal but then the electric potential will equalise between the cathode and the terminal (through the ammeter), which reduces the potential at the positive terminal (through the battery), and then the potential will equalise between the positive terminal of the battery and the anode of the vacuum tube, in the process replacing the electrons that were bumped off it, that were shot through to the cathode. Is this how the reverse current is created (effectively recharging the battery to some extent)?
We have read in earlier classes that in photoelectric effect incident photon acts on metal surface due to which electrons are emitted from metal surface . But here you are using electric current instead of photons . Can you please explain why?
Yes. One could, of course, insert it in the anode branch of the circuit as well. Since this is a series circuit, the current will be exactly the same. Please note that in technological applications (photomultiplier tubes), the metal surface that is illuminated is usually called the "photo cathode" and that the polarity of the external voltage source is opposite. Why? Because in a photomultiplier tube we are trying to capture every single electron, so rather than trying to suppress the photo current, we are trying to maximize it.
Sir recently Government announced a Rs 6000 cr funding initiative for Quantum technology development in India? According to you a Fresher or a job going person in mechanical engineering who has interest in Quantum technology hence to get a research job what in Quantum technology branches what should be his/her first foremost basic step to start with? Can you please guide us with this???.
@FortheLoveofPhysics If the observer is moving at relativistic speed. He will observe a red shift or blue shift depending upon whether he is moving towards or away from the source. So if a target is accelerated to relativistic speeds, photon with frequency lower than the threshold frequency should be able to produce electron emission. Has this been ever confirmed experimentally? On the other hand, we know that speed of light is constant for all inertial observers. Irrespective of whether they are moving with uniform velocity or are at rest. So the speed of light cannot be anything other than c in all the inertial reference frame. So a moving target is no different than a resting target for the light. Hence we should see no photo-electric effect when shining a light of frequency lower than the threshold frequency. Which of these two contradictory observations true? Or is there a way to resolve this contradiction?
No, but there can be a scattering process in which the electron and the photon change their energy and momentum. If the photons have high enough energy, they can also create additional electron-positron, muon or even quark pairs.
All these processes are very close to the surface. For metals like gold the optimal thickness of a photocathode material is on the order of 10nm (a few dozen atomic distances), for semiconductor photocathodes it seems to be about an order of magnitude larger (100-150nm for the few papers that I could find in a hurry that report the optimal thickness).
Light is incident on the positive terminal (anode) and photoelectrons go into the negative terminal (cathode). This setup is necessary to introduce a potential barrier that the electrons need to overcome with their KE.
thank you, prevent effect of global warming, minerals and temperature of water and air from sea are huge source of energy, reduce more than 50% using fossil fuel, fresh water, fertilizer(minerals+o2,n2,C), zero pollution, economy will rise by using jet plasma machine and compressed gas(Air) in isolated structure in water pool with more than 80 % efficiency, it has two vertical cylinders, in first level it transfers compressed gas(hot air) temperature from engine to sea water in pool for steam electric generator, steam combines with high cold Air pressure to produce pure water and electricity , New energy from sea will change world soon, there are other source of energy that with international cooperation in coastline we can reduce effect of global warming, further more we can prevent these phenomena like cyclone and flood and wildfire by using this hot seasonal atmospheric condition, recent years in summer, geothermal energy happens in surface of coastline, there are many countries in coastline with seasonal hot weather and water condition in comparison with middle Ocean, its more than 12 degrees , in sum-up, by using this energy not only is economical but also reduce global warming in countries like Japan, China, India, Mediterranean countries, Iran, Brazil, Mexico, Us, Canada, (Africa and Arabian countries....) . I invented new method base on air pressure rules and quantum physics ionization sea water minerals in strong dynamic permanent magnet(SMCO) with special frequency(1500or 3000)/minute bases on paramagnetic and diamagnetic particles and electrical microwave electron wave field and electric chemical reactions and photon wave from semiconductors with special angle Cations like(K+, Mg++, Na+, H+, H++, li+, H2, ...) are transferred to in the second level into up level by vacuum pump from storage into combustion chambers and they combine with O2 and N2 ,... as major part of fuel for producing electricity and fresh water and fertilizer. this machine produces 150Megwatt/hour and 20000M3/DAY fresh water and fertilizer. 7 methods zero pollution for reducing global warming I mentioned in my profile. (G20 countries can solve these phenomena).
If light energy was quantised in Photoelectric Effect, now it is colliding with electrons in the Compton Effect :) th-cam.com/video/oTNiJVdEyCc/w-d-xo.html
About Millikan's unnoticed until recently mistake read "We Have Lost a Half of Solar Energy, the Half that We Never Had".
No one can understand quantum physics according to Feynman but we are lucky to have you. you have explained it in the best and easiest way possible. I haven't seen better way from this. Thankyou Sir... 💕💕❤️
You are an outstanding teacher. I enjoy it more than Netflix
You are my god
31.10
The moment that you feel the satisfaction of being able to understand and explain even a small part of the universe.
Very well explained. Better than Einstein himself. Congratulations
Love that sigh towards the end, not a sigh of tiredness or disappointment, but rather of a job well done and maybe of some admiration towards Planck and Einstein. Your transition from classical to the quantum world in the last couple of lectures is brilliant. I enjoy Physics in layman’s term (a little Calculus and Diff Eqs is OK). I didn’t know about this sequence of events between Black Body Radiation, UV Catastrophe, Planck’s resolution and Einstein’s PEE.
No more googling, you’re now my Master and I’m your Grasshopper.
I totally agree with you.I also noted the sigh towards the end of lecture.Max Plank to Bhor to Enstein connection is amazing.
you're absolutely amazing at what you do. definitely one of the best lecturers out there
excellant lecture...this professor is a brilliant teacher
Bengali people are naturally brilliant and genius...most of them....some atel guys also exist
The best video on the photoelectric effect. Well done!
Beautifully explained.
A good book even wouldn't be able to explain a concept as good as he can.
U are the type of teacher ..which makes student feel physics ..nd feel why are we studying physics ..u make it interesting..in every way possible..which very few teachers do..nd when u teach ..u give details bout every small thing in ur knowledge..which is truly appreciable..best teacher❤️
Sir I lack the best words to express not only your teaching methodology but also how you make Physics look simple and interesting. You explain the concept of Photoelectric Effect in a hilarious way, making it get perfectly absorbed in my brain. Thanks so much. I am subscribing to your channel. It can be wonderful to attend your live classes online incase you have an online teaching and discussion platform.
Each lecture is a masterpiece in itself
I have no words sir.. best explanation on the TH-cam till now
I first watched your video years ago but only just now that I finally get to video-hopping on your channel. I am hooked. Thank you, I hope you'll never stop.
Thankyou so much sir. You are really energetic. : )
Sir, tusi great ho, you've made quantum mechanics easier to study for me.
the passion you put into teaching made me listen and understand better
Good teaching and breakdown of such a challenging concept
A dedicated and passionate teacher... Great lecture😊...
100th comment on the video. You are absolutely unreal. The passion radiates from the way you speak and move. Bloody Brilliant! Thank You.
You are a wonderful lecturer…. Thank you sir!!!
Oh! Marvelous teaching skill!
Hats off to your passion for teaching. The lecture was exciting the whole time.
How do you theoretically calculate the classical time delay (hours, days, etc. as you mentioned)? How do you theoretically calculate the quantum mechanical time delay (10^-9 sec as you mentioned)?
Excellent teaching
Sir your particle physics class is simply superb....we are from telangana...preparing for JL......thank you so much 🙏🙏
Thank you sir, for this
Thank you sir. We need more teachers like you. Respect.
He is best man no word to experse
I look up a physics topic and add your name in the search because I know you will give the best explanation
u r more than great teacher
You are a great teacher, god bless uu sir🙏🙏🙏
My respect for you is redoubling day by day sir....❤❤
You are a gem sir
Great video as usual. Thanks.
Awesome Explanation sir
Thank you very much for this wonderful explanation to make your students understand. May God bless you and give you a long life to serve the world.
God level. Thank you so much sir 🙏🙏💝
So pleasant learning from u
Love from Pakistan to u
Sir, can we have Foucault pendulum lecture? Coz your derivations and explanations are way easier to understand..
Currently in BSC Physics 1st year.
Hello there! Could you make videos for Astronomy too? It is a topic that I don't see covered in much detail online
Great presentation
Congrats on a very astute, clear and comprehensive presentation. Cheers.
18:00 failure of classical
You're explanation is mind blowing sir 💜
Sir you're such a legend 🙏♥️ love form Odisha ❤️
Thank you Sir, your explanations are gold worth.
The interest. And the concept's 🔥
Awesome explanation sir
I love your channel!
Thank you very much!
Thanks a lot sir, I have one question please, The cross section per atom depends upon approximately Z* for high atomic number materials and on Z4.8 for low Z materials. Since each atom contains Z electrons, the coefficient per electron depends upon Z³ and Z3.8 for high and low Z materials respectively. Since the number of elec- trons per gram is more or less independent of Z, we would expect the mass coefficients to vary as Z3 and Z3.8 for the two classes of materials. These statements are at best rough guides. That the variation of the mass coefficient depends roughly on Z³ can be seen from Figure 5-5. Above the K edge in lead, the coefficient is one thousand times as large as it is in water (slightly over 3 cycles on the vertical scale), while their atomic numbers of 82 and 7.5 are in the ratio of about 10:1.
If you can explain it ,
This isn't an atomic process. The electrons that are absorbing the energy of the photon are in the conduction band of the metal, i.e. their binding energy is much lower than the ionization energy of the individual atoms will suggest. In practice we also have to consider the thermal excitation of the conduction band, so unless the metal is cooled, there will be a considerable amount of thermal "smearing" of the work function.
I understand before the light is shone on the anode there is no current across the vacuum tube. Whilst the excited electrons might fly against the force of the electric field to the cathode, the momentum of their flight is not going to push them any further than the cathode; its not going to push them through the wire to the negative terminal of the battery (something else might though).
I expect the arrival of the electrons at the cathode reduces the electric potential at the cathode (raises its negativity) compared to that at the negative terminal but then the electric potential will equalise between the cathode and the terminal (through the ammeter), which reduces the potential at the positive terminal (through the battery), and then the potential will equalise between the positive terminal of the battery and the anode of the vacuum tube, in the process replacing the electrons that were bumped off it, that were shot through to the cathode.
Is this how the reverse current is created (effectively recharging the battery to some extent)?
Sir shouldn't the electrons go from cathode to anode???
We have read in earlier classes that in photoelectric effect incident photon acts on metal surface due to which electrons are emitted from metal surface .
But here you are using electric current instead of photons .
Can you please explain why?
Great video
Excellent
if f' is the threshold frequency , we have the emkssion of photoelectrons for f> or =f'
emission
Very thanks sir
Sir iit jaam ke liye book ko study krne ki need hai please reply 🙏🏼
Thankyou sir
You are a great teacher , sir ❤
If you don't mind , would you please tell about the courses you studied, sources where you get all the knowledge from?
He is the Prof of Physics
IIT Delhi
I love you alot sir from Pakistan
Sir, is this is the correct position of Ammeter to measure photo electric current?
Yes. One could, of course, insert it in the anode branch of the circuit as well. Since this is a series circuit, the current will be exactly the same. Please note that in technological applications (photomultiplier tubes), the metal surface that is illuminated is usually called the "photo cathode" and that the polarity of the external voltage source is opposite. Why? Because in a photomultiplier tube we are trying to capture every single electron, so rather than trying to suppress the photo current, we are trying to maximize it.
Sir flow of electrons cathodes to anode right 😢 I'm getting confusion about experimental setup 😢
Yes it will flow *against* the potential difference
thanks sir
Awesome
Sir recently Government announced a Rs 6000 cr funding initiative for Quantum technology development in India?
According to you a Fresher or a job going person in mechanical engineering who has interest in Quantum technology hence to get a research job what in Quantum technology branches what should be his/her first foremost basic step to start with?
Can you please guide us with this???.
@FortheLoveofPhysics If the observer is moving at relativistic speed. He will observe a red shift or blue shift depending upon whether he is moving towards or away from the source. So if a target is accelerated to relativistic speeds, photon with frequency lower than the threshold frequency should be able to produce electron emission. Has this been ever confirmed experimentally?
On the other hand, we know that speed of light is constant for all inertial observers. Irrespective of whether they are moving with uniform velocity or are at rest. So the speed of light cannot be anything other than c in all the inertial reference frame. So a moving target is no different than a resting target for the light. Hence we should see no photo-electric effect when shining a light of frequency lower than the threshold frequency. Which of these two contradictory observations true? Or is there a way to resolve this contradiction?
Professor I wonder is it possible for an individual electron in free space absorb photon ? Not in an electron atomic shell .
No, but there can be a scattering process in which the electron and the photon change their energy and momentum. If the photons have high enough energy, they can also create additional electron-positron, muon or even quark pairs.
@@schmetterling4477 thank you
Your great sir,,, but you take a pinch of time to upload new videos. 😊❤
Sir, one question I had gone through is ..what is the maximum distance a photon can travel inside a metal in photoelectric effect?
All these processes are very close to the surface. For metals like gold the optimal thickness of a photocathode material is on the order of 10nm (a few dozen atomic distances), for semiconductor photocathodes it seems to be about an order of magnitude larger (100-150nm for the few papers that I could find in a hurry that report the optimal thickness).
Ok sir... Thank you
@@cnusrinivas226untill , the energy of photon < h×f
Sir csir NET ki bench kab start hogi???
It will start first week of June
Sir next video please
Sir it,s 10 days I am waiting for another video .sorry sir if I disturb you
We want COMPTON SCATTERING, we want COMPTON SCATTERING... Bet you haven't heard that chant before. Haha
Coming up :)
sir UPSC physics optional related course bhi start karege kya...... ya abhi koi vichar nhi ?????????
First viewer❤
❤❤❤
The light is incident on cathode and not on anode
Light is incident on the positive terminal (anode) and photoelectrons go into the negative terminal (cathode). This setup is necessary to introduce a potential barrier that the electrons need to overcome with their KE.
thank you, prevent effect of global warming, minerals and temperature of water and air from sea are huge source of energy, reduce more than 50% using fossil fuel, fresh water, fertilizer(minerals+o2,n2,C), zero pollution, economy will rise by using jet plasma machine and compressed gas(Air) in isolated structure in water pool with more than 80 % efficiency, it has two vertical cylinders, in first level it transfers compressed gas(hot air) temperature from engine to sea water in pool for steam electric generator, steam combines with high cold Air pressure to produce pure water and electricity , New energy from sea will change world soon, there are other source of energy that with international cooperation in coastline we can reduce effect of global warming, further more we can prevent these phenomena like cyclone and flood and wildfire by using this hot seasonal atmospheric condition, recent years in summer, geothermal energy happens in surface of coastline, there are many countries in coastline with seasonal hot weather and water condition in comparison with middle Ocean, its more than 12 degrees , in sum-up, by using this energy not only is economical but also reduce global warming in countries like Japan, China, India, Mediterranean countries, Iran, Brazil, Mexico, Us, Canada, (Africa and Arabian countries....) . I invented new method base on air pressure rules and quantum physics ionization sea water minerals in strong dynamic permanent magnet(SMCO) with special frequency(1500or 3000)/minute bases on paramagnetic and diamagnetic particles and electrical microwave electron wave field and electric chemical reactions and photon wave from semiconductors with special angle Cations like(K+, Mg++, Na+, H+, H++, li+, H2, ...) are transferred to in the second level into up level by vacuum pump from storage into combustion chambers and they combine with O2 and N2 ,... as major part of fuel for producing electricity and fresh water and fertilizer. this machine produces 150Megwatt/hour and 20000M3/DAY fresh water and fertilizer. 7 methods zero pollution for reducing global warming I mentioned in my profile. (G20 countries can solve these phenomena).
💜💜
I believe that Einstein will be proud of you from hell. You nailed it you are gorgeous ❤
hindu is studying from HRC
The thumbnails r getting ridiculous 🤣
hindi m bhi bolo to accha rhe
I have a question, what frequency represent ?(for photon?)
Thank you sir!
❤❤❤❤