great thing to have this channel, i don't understand most of it and id have to go back to several hours worth of video to do so. But having a trust worthy source of information for free, and not only that, but someone to cares to explain that information to you, i think is a great way to improve society. have my love mit. all universities should have video lectures.
What a great lecture. I did not understand the last example at 1:10:00. How can it go as fast as the speed of light? The phase velocity vector has a certain value, and if anything, the constituent of that vector perpendicular to the beach is gonna be equal to the phase velocity as theta approaches zero. Did he mean as theta approaches 90 degrees?
As you see in the figure, the angle he's taking about is not between velocity vector and the beach, but between incident wave (node or anti-node line) and the beach. So 0 is correct and it's the same as 90 between the velocity vector and the beach.
Nishant Shankhwar i have watched both versions and I think the one of prof WL is vivid and interesting but this version of Prof Lee pays more attention to math and details which are helpful to the later 804 course lectured by prof BZ
In the last 3 min, he showed an example of water wave. I just don't understand how the phase velocity is calculated. How does it go to zero when the angle theta approches zero?
Does anyone know how to smoothly simulate carrier and envelope waves in a computer simulation? I have tried with ggplot in R, but repeated plotting results in a strobe like effect which is not visible in Prof. Lee's simulation. Thank you for your help.
Vg=c/( n(lambda) -lambda*{dn(lambda)/d(lambda)} ) can any one verify This formula? ... 😢 Please help .. Questions:- n(lambda)=1.5 +0.6×lambda Find Vg=?
great thing to have this channel, i don't understand most of it and id have to go back to several hours worth of video to do so. But having a trust worthy source of information for free, and not only that, but someone to cares to explain that information to you, i think is a great way to improve society. have my love mit. all universities should have video lectures.
Awesome demonstration of phase and group velocity.
49:24
58:32
This lecture finally made it click for me. Thank you.
What a great lecture. I did not understand the last example at 1:10:00. How can it go as fast as the speed of light? The phase velocity vector has a certain value, and if anything, the constituent of that vector perpendicular to the beach is gonna be equal to the phase velocity as theta approaches zero. Did he mean as theta approaches 90 degrees?
As you see in the figure, the angle he's taking about is not between velocity vector and the beach, but between incident wave (node or anti-node line) and the beach. So 0 is correct and it's the same as 90 between the velocity vector and the beach.
Finally, i understand what is phase velocity and group velocity
This is not hard at all lol
Its fun to watch these at 1 am.
11 pm for me
3:00ish harmonic waves can still be used, but in highly specialised research
A very good lecture. But I have also listened to Prof. Walter Lewin's lecture on same topic, which was absolutely wonderful.
Nishant Shankhwar i have watched both versions and I think the one of prof WL is vivid and interesting but this version of Prof Lee pays more attention to math and details which are helpful to the later 804 course lectured by prof BZ
@@roseruby9262 indeed, Mr Lee is more mathematical
The michael jackson joke, this guy is the next Louis CK. Pure, comedic brilliance, just incredible. Amazing.
43:37 phase velocity
Typo in the wave equation. One of the partial-d t^2 should be partial-d x^2, am I right?
Yes, he corrects it at time 20:10
Very quality lecture!!❤️💜❤️💜🇧🇩
In the last 3 min, he showed an example of water wave. I just don't understand how the phase velocity is calculated. How does it go to zero when the angle theta approches zero?
This is such a great lecture.. I wanted to turn it off to go to bed because it's 2.A.M. but I just couldn't ...
why does the solution remain the same when we add stiffness term?
at 6th min, equation written is wrong. on the right side, it should be spatial variation of the function
Awesome lecture.
Does anyone know how to smoothly simulate carrier and envelope waves in a computer simulation? I have tried with ggplot in R, but repeated plotting results in a strobe like effect which is not visible in Prof. Lee's simulation. Thank you for your help.
really a good explanation !
Awesome!!
wait windows and ubuntu at the same time ?
This becomes less confusing when you realize that v means the velocity if α = 0. It doesn't mean velocity when α ≠ 0, (ω/k is always the velocity.)
Indeed, you are correct. v should have been written as v0
Thanks! I was confused but then read your comment
The wave function is incorrect
The right hand side should be the second order partial derivative of ψ w.r.t. x instead of t.
Vg=c/( n(lambda) -lambda*{dn(lambda)/d(lambda)} ) can any one verify This formula? ... 😢 Please help ..
Questions:-
n(lambda)=1.5 +0.6×lambda
Find Vg=?
Ok, then you corrected that, good
Pretty dense lecture
ideal spring equation is wrong written.
🖖❤️
I am really smart asian man. My english is not so good but i try. hehehe
If you use this kind of strel-o-ge.......... you mean strategy.
Square pouse............ you mean square pulse............ i love these people who teach but can't speak english.
Then how can I understand his lectures on university level physics?
@@santiagoarce5672 2x speed xd
@@fehmi35 Yeah exactly.
I always wonder why the American universities are invaded by Chinese instructors. Are the American scholars not good enough?