i love how he hopes we find it "reasonably interesting," lol. not "incredibly" interesting or even "very" interesting. just "reasonably" interesting. :D
0:38 i love that you always have such good examples to explain such phenomenons. this has actually something to do with the wave character of light. the example with the car is perfectly fitting. the light reenters the medium it just left due to its diagonal micro movements and looses speed. reentering the fast medium again, it made a curve.
Sal, you are a lifesaver! Summer classes have us learning this whole playlist in 3 days and it's going to make up around 25% of the final. I was so stressed but 3 hours of sitting down and watching this playlist actually makes it manageable. Thank you, thank you, thank you!!!
I swear no one teaches like Khan Academy! This is amazing, I had been trying to understand this whole concept from other videos, but for some reason, all those teachers or speakers assumed that everyone is a genius and automatically knows what they are talking about so instead of explaining, they just carry on saying a bunch of words that I have never had of.
Once you had explained total Internal reflection, I whipped out my scale and even tried it in practical....and it worked....Thanks for explaining in ruch simple words and making it understandable
Thanks for this video, helped explained this better rather in class. Fully understood the concept behind critical and total internal reflection. - grade 10 student
The core has a high refractive index and it is surrounded by cladding that has a very low refractive index. There is a "cone of acceptance" (where you seem to have gotten confused; the air to 'glass' transition is not fundamental to internal reflexivity) such that for snells law, rearranged and sin90->1 crit. angle = sin^-1 (1 / huge n). the argument approaches 1/inf. and sin inverse of zero in 90 degrees. That is to say, that only if light approaches at 90 angle will it escape. :3!
thank you! It only takes me 8 mins to understand what total internal refraction is. I can't even figure out what my teacher is teaching before watching this video.
Thanks a lot for this video! It's nice to see you're constantly uploading lots of videos. Many of them are so helpful! Thank you so much for keeping this channel up and going.
So is it safe to assume that regardless of the media the ray is initially in and the final media it is in, we can use the media with the lower index of refraction in the numerator, and the higher index in the denominator? Because there's been a couple situations where I get undefined errors in my calculator. For example when a ray goes from glass to air and I use the glass in the numerator and the air in the denominator because I'm thinking n1 = glass since it was in glass first.
A good point but sin(θi)/n cannot be greater than 1. No material has a refractive index of less than 1 and sin(θi) cannot be greater than 1 which means sin(θi)/n will always be between -1 and 1, inclusive. Hence, Snell's law is valid.
@arenms believe it or not many people enjoy reading / learning. I read an article about khan and his academy in a magazine a while ago and he appears to be a very humble guy genuinely wanting to help others. He enjoys reading which is how he learned all this stuff. And honestly what he teaches is relatively basic stuff. Im a medical student and now that is mentally / physically draining.
Man, why cant i have teachers like this? Mine just sits there and talks like i can imagine what the .....*.... he is talking about. Thanks.
Same💔
i love how he hopes we find it "reasonably interesting," lol. not "incredibly" interesting or even "very" interesting. just "reasonably" interesting. :D
@Enrique Duran Mynenko yes
@Enrique Duran Mynenko You just asked me five days ago bro.
Alive?
@@omaralsaheb9737 bro 😭
once again, I don't know what would I do without your videos. so much love to you Mr. khan
1:26 to 2:45 is what i found most useful, thanks mate
0:38 i love that you always have such good examples to explain such phenomenons. this has actually something to do with the wave character of light. the example with the car is perfectly fitting. the light reenters the medium it just left due to its diagonal micro movements and looses speed. reentering the fast medium again, it made a curve.
Sal, you are a lifesaver! Summer classes have us learning this whole playlist in 3 days and it's going to make up around 25% of the final. I was so stressed but 3 hours of sitting down and watching this playlist actually makes it manageable. Thank you, thank you, thank you!!!
I swear no one teaches like Khan Academy!
This is amazing, I had been trying to understand this whole concept from other videos, but for some reason, all those teachers or speakers assumed that everyone is a genius and automatically knows what they are talking about so instead of explaining, they just carry on saying a bunch of words that I have never had of.
Thank you, Mr. Khan! You are the one who helps me to escape from my boring physics lesson!
I appreciate the analogy of the car going from one surface to another. That's an easy one to remember.
Once you had explained total Internal reflection, I whipped out my scale and even tried it in practical....and it worked....Thanks for explaining in ruch simple words and making it understandable
Thxs a million!! Khan Academy videos have been helping me for 2years now! Sal's the best at making complex things simple!!
thank you so much ! I litteraly study in french and english is not my first language and i’ve learned more from this video than from class😭😭
This was the one part of my optics subject in school i never understood. Thanks for explaining clearly!
Thank you SO much! This has been immensely useful and makes far more sense than it did before I watched the video! Many thanks
My teacher has been explaining it for the past hour and I had no clue what she was saying. I understood right away after watching this video!
Reasoning it out, your explanation from 0:28 onwards was fantastic - it just immediately clicked. Thanks for your help!
I need my teacher teach like you,interesting and easy-understanding
Thanks a lot. My teacher made the explanation complicated. This sums up what I need perfectly.
waaay better than my teacher. I love khanacademy
This wil help me so much for my physics test tomorrow!
Thanks for this video, helped explained this better rather in class. Fully understood the concept behind critical and total internal reflection. - grade 10 student
You have carried me through my GCSE's
Youve helped me in so many of my classes...... i hope you know a lot of people really appreciate this stuff. Thank you. Thank you so much.
7:24 is a glitch in real life
3:29 also glitch
7:39 another one!
I found it reasonably interesting! Thanks! :3
Where have you been all my life *sigh*
I want to keep it simple. You do great!!
ooooooooooooooooooohhhhhhhhhhhhhhhhhhhhhhhhhhhh 1:40 shoot I GET IT now!
Is this what causes all reflection? Do mirrors, for example, have such high refractive indexes that they reflect all light?
That is a very good question
The core has a high refractive index and it is surrounded by cladding that has a very low refractive index. There is a "cone of acceptance" (where you seem to have gotten confused; the air to 'glass' transition is not fundamental to internal reflexivity) such that for snells law, rearranged and sin90->1
crit. angle = sin^-1 (1 / huge n). the argument approaches 1/inf. and sin inverse of zero in 90 degrees.
That is to say, that only if light approaches at 90 angle will it escape. :3!
Learned more in 6 minutes than an hour with my college professor... thanks so much.
thank you! this video better my understanding :)
i love your voice and teaching skills Sal, thank you so much for taking the time to make these wonderful videos you are awesome
This is great! Havin a physics test tomorrow! This really helped me to understand what TIR Is!
The way u explain is top man 👌👌
Oh my God, they never told us where the 1 comes from!! Thanks a lot! ^^ You're so awesome! :D
Thx!!! This helps so much I hope I wont fail my physics exam
These videos are the only reason that I'm able to pass my physics exam.. THANK YOU SO MUCH!
Thaaanks , that was really helpful !
This makes so much more sense!
You're a life saver Mr. Khan. Now I know I won't fail my physic exam.Lots of love 💜
Thanks a lot..!! It was very helpful 😁..
Thanks you very much for the video I was facing trouble understanding total internal reflection...... Thanks a lot
Thank u! This helps me a lot doing my school works! An amazing and engaging lesson!
thank you! It only takes me 8 mins to understand what total internal refraction is. I can't even figure out what my teacher is teaching before watching this video.
Great video for understanding reflection,refraction and critical angles!
Thank you so much, you made this waaaaay easier
Respect🙌🙌
Thank you very much i have a test tomorrow and i didn't know how to do it
MODY 14 me 2
+MODY 14 me 2
super AmaZing.....I'd rather bunk college and sit at home and learn from you......You"re amazing!!
Thanks a lot man! I have an exam tomorrow, and you just helped me understand Snell's law and the whole theta critical thing a lot better!
Wow dude it’s been 8 years now u would be doing a job now right?
Dang now its been 10 years
This really helped a lot, I'm 14, i need to learn this in foreign German though :c this is going to be so hard xD
NZVON where did you come from?
Arolema Prarath wat
Thank you Khan Academy... You guys are always life savers !
Sooooooooo helpful, my exam is tomorrow and this is really going to help
right through d basics ! nailed it ! Sal u rock !
Man you js saved my grade tysm
Thank you SO MUCH!!!! This helped to explain the concept and reasoning of the critical angle.
Most beautiful channel i have ever seen.❤
Thank you so much!! It all makes sense now!
Cleared things up for me, thanks!
Thank you so much, you really helped me for my test!
thank you so much,you are the best Physics teacher in the entire world!! by a student from HONG KONG
That's a great programme...
It helps me a lot!!!
Thanks a lot for this video! It's nice to see you're constantly uploading lots of videos. Many of them are so helpful! Thank you so much for keeping this channel up and going.
bless you sal
thank you so much, man. my teacher has such a strong German or Austrian accent and its hard to understand anything thanks so much
4:50 u can just calculate it with ur calculator and put the unknown given as an X
Thank you Mr.Khan ,your videos are very helpful .
The best explanation ❤️👏
Sal Khan is the GOAT🐐
So is it safe to assume that regardless of the media the ray is initially in and the final media it is in, we can use the media with the lower index of refraction in the numerator, and the higher index in the denominator? Because there's been a couple situations where I get undefined errors in my calculator. For example when a ray goes from glass to air and I use the glass in the numerator and the air in the denominator because I'm thinking n1 = glass since it was in glass first.
I love this guy's calculator 😍
helped me out alot. Thank you.
helps me alot. thanks!
what a concept of fiber optics wow amazing thanx alot
This video helped alot!!!!
you are a GENIUS! Thanks alot
Good
The car example was brilliant
Thank you ，that was really helpful
sir you just saved my life
Thank you SO much for this!!!!
this guys a champion
In our case -1 ≤ a ≤ 1 and b ≥ 1. And so, -1 ≤ a/b ≤ 1.
thank you so much was very halpful😉
Amazing , just amazing 👌🏻👌🏻👌🏻😬😬😬
very good . Thank you so much.May Lord bless you
A good point but sin(θi)/n cannot be greater than 1. No material has a refractive index of less than 1 and sin(θi) cannot be greater than 1 which means sin(θi)/n will always be between -1 and 1, inclusive.
Hence, Snell's law is valid.
thanks, this helped alot
Nice explanation 👌
Nailed it.awesome explanation
You explained it very well sir :D
Thank you sir!!!
@arenms believe it or not many people enjoy reading / learning. I read an article about khan and his academy in a magazine a while ago and he appears to be a very humble guy genuinely wanting to help others. He enjoys reading which is how he learned all this stuff.
And honestly what he teaches is relatively basic stuff. Im a medical student and now that is mentally / physically draining.
This is awesome!
Thank you so much
THANK YOU THANK YOU THANK YOUUUUUU
Thanks a lot 🤪🤪it is helpful😁
اشاهد هذا الفيديو عام 2022 ومر عليه 12 عام . اتمنى من يقرأ هذا التعليق يترجمة ويفكر في تعلم اللغة العربية لأنها رائعة
Thank You
well explained