Young's double slit introduction | Light waves | Physics | Khan Academy

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We can see interference in action if we shine laser light through two slits onto a screen. Created by David SantoPietro.
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6 июл 2014

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Комментарии : 358

@ThatDudeEddiee0 6 лет назад

I spent 1 hour in lecture and 1 hour in lab and was so confused as to understanding the constructive/destructive interference, the first minute at 40 seconds answered just that. BIG THANKS.

@tamilachirajeshwari701 2 года назад

Can u tell me definition of constructive nd destructive interference...🙄

@IdunDied 2 года назад

@@tamilachirajeshwari701 When waves of same kind in cross they combine to make one wave at that point. Like if a high water wave went into another higher one it would be higher at the point they cross because the water is being lifted up by both. Constructive is when the waves add together to make a bigger wave. [aka when they cross you add amplitude together]. However if one wave was in the other direction (negative) to the other (positive), if they were at same height (amplitude) but in those opposite directions they cancel out so there is effectively no wave at that point. That's why it's destructive. Constructive and destructive usually mean where the waves are either crossing at max height in same direction (constructive) to make new one double the height, or they are same but opposite direction so completely cancel (destructive).

@KibyNykraft 2 года назад

Everyone seems confused... Why is there no interference pattern on the first wall? How do we know the photons pass gently uniformly through the next wall slits in the same manner as through the first? Let's follow the classical mechanics here of early Einstein and of the the classical physics, assuming that the photons are discrete pieces of matter : Once they enter through the first slit from the candle or lamp, there is a second wall with another slit. It is only needed a small discrepancy from the light path to create an interference pattern on the wall number 2. What the case was in Young's early experiments inspired by Huygens who of course understood that there had to be an interference pattern, was just that he assumed that photon rays would pass uniformly through all slits. But that we don't know just out of nothing; it only takes a small variation of the light path to hit the sides of the slit in the next wall, meaning there will be small pattern of interference. Some of the photons would reflect from off the back of the first wall, already having a changed path while or if going through slit 2. And so forth and so forth. Aggregated with the already discrepant variation from the main ray. Thus it has to be a wider and wider pattern of interference.

@amartyachoudhury8991 8 лет назад

Beautiful explanation.... especially that part where you explain how the wavefronts from the two slits interfere constructively or destructively; and finally on the screen... very helpful; thanks a lot

@muhammadtouhid998 5 лет назад

first time in my life, i have realized what the circular form of wave representation means, all after passing everything, huh

@sahilyadav3783 4 года назад

@akshayjagtap9338 3 года назад

Exactly bro

@nisha1180 2 года назад

True

@CorisWorld404 4 года назад

Beyond incredible instructor!! He not only explains the right way but also shows you common misconceptions to avoid.

@TheGatoroberto 7 лет назад

Thanks ,good video and made very clear ... probably the easiest and most understandable explanation that I have ever found about this experiment

@Silly825 5 месяцев назад

This gonna save me

@benisman 4 года назад

This has been really helpful for my A-Level studies, thank you so much. I finally understood how to implement the constructive and destructive interference pattern formula w=λD/s

@johntindell9591 6 лет назад

i never had an intuitive understanding until i watched this video. The impact you are having on the world is deeply profound.

@AlonePlaying 4 года назад

Dude, i'm from Brazil and I'm really thankful for this video. I wasn't understanding a bit of what my college's teacher was saying, you'll save my exercises. Keep doing a great job!

@annearts5 6 месяцев назад

U learn that in college?? We have this is 12th grade in India.

@majsterektv7528 6 лет назад

I just relized my teacher is useless as I always heave to learn from the internet

@96mohormukherjee56 6 лет назад

Hahahaha same @majsterektv

@e0413836 6 лет назад

Not sure it's the teacher's fault - realized and have! Oh there is only so much that can be built from the basic lego kit.

@praharshsingh2095 5 лет назад

i dont even call my teacher a teacher

@cnu9948 4 года назад

Its your fault first did you ask the teacher or not

@litinggoh1169 3 года назад

@@cnu9948 Maybe he asked his teacher, but his teacher doesn't even know how to explain / explain in a way that's to difficult to understand / repeat the same thing that's mentioned in the textbook. Because that's what my teacher does. RU-vid is much better than some of my teachers to be honest.

@maazali9456 8 лет назад

seriously i just understand the whole concept thank you very much.GOD bless you

@bardotons 8 лет назад

thank you for speaking quickly and getting to the point!!!! great video.

@ydkathy5771 4 года назад

ur ten minutes have covered the content that my teacher spent classes talking about with clearer explanation. Thanks a lot :)

@zahrashahabinezhad 4 года назад

Absolutely fantastic videos on this topic. I finally understand this. Thank you!

@HM-rc7nn 8 лет назад

A great explanation, for which I was looking for!! Thanks for such videos:)

@ishantripathi9707 9 месяцев назад

Oh boy! Oh boy! Oh boy! Man you explained the concepts so clearly and simply. Hats off!

@johnparks6936 8 лет назад

I went through so many videos... And this one finally did it for me!! Thank you so much. Here's what I couldn't understand: why were they showing waves as propagating lines when, in reality, they were like the sine and cosine waves with peaks and troughs? This videos answered that question and even explained where they would interfere constructively and where deconstructively, Beautifully explained!

@MrWolfchamp-xi3cu 7 лет назад

Didn't work for me. Still don't know what destructive interference is. Can't even find any real life examples of it. Just never see it happen. Waves don't cancel, PERIOD. If i turn on two flashlights i just get more light. If i turn on two radios i just get more sound. NOTHING EVER gets CANCELLED!!!!!

@OmriToren 7 лет назад

you're doing it wrong! you need one source of light (1 flashlight, radio, sun,...) and a screen with 2 slits on it (hence the name Double Slit experiment!) if you display that light onto a blank screen you'll see interference patterns! this wikipedia picture shows it animated upload.wikimedia.org/wikipedia/commons/3/33/Doubleslit3Dspectrum.gif -- if you don't understand the physics of it, look at the philosophy behind it! i find that easier to understand!

@MrWolfchamp-xi3cu 7 лет назад

The interference is those blue dots on in the green of the pic right? plus what is the philosophy behind this?

@OmriToren 7 лет назад

yes! the blue would be the perfectly destructive interference (two troughs) the yellow would be the interference of one peak and one trough (+1 + (-1) = 0) and the green would be the positive peaks of light! the philosophy behind this experiment is thomas young trying to prove that light is a wave based on his experimental results. his argument is as follows: if my theory is true (A), then when i set up my experiment i will see the results that I expect (B). he does see the results of (B), therefore (A) must be true! this is a philosophical fallacy that results in his theory being confirmed (not proven) and is called affirming the consequent

@MrWolfchamp-xi3cu 7 лет назад

One peak and one trough? No idea what that means. If the blue is the destructive then that means that yellow is constructive right since its brighter that green and blue?

@MRAXELGRINDER 7 лет назад

This is a really great video, thank you so much, it helped a lot,I am grateful for the time you took to explain this, please keep it up :)

@geniusm3521 2 года назад

The person, who understands best, explains best! perfect lecture about double slit experience. thank you

@aishwaryagorti8412 6 месяцев назад

This really helped me to understand what actually happens in the experiment... This was so helpful. Thanx a lot

@bluecloud3059 6 лет назад

Thank you so much. The best video for explaining Young's double slit experiment.

@muhammadabdullahae2480 5 лет назад

Brilliant superb I could not understand it from many teachers but this let me understood

@PeaceboneGotFound Год назад

THANK YOU for explaining this so well!!!

@sreyasthejas4715 7 лет назад

thank u soo much for the video . one of the very best videos on interference out there.

@fajarprasetya_jamulogi 6 лет назад

wonderful. . it's made me so relief. . thank You very much bud

@effectbest7532 7 лет назад

Thanks man this cleared all my doubts ....Well explained

@somnathganapa5789 8 лет назад

Thank you for explaining the shape of the light waves before it enters the two slits! My textbook completely ignored how strange it looked!

@huanganan700 2 года назад

Thanks so much for perfectly visualizing the process of light diffraction. Always love Khan Academy😄

@Inovb 9 лет назад

That's explained very well thank you.

@melynx1159 3 месяца назад

This helped me trillions! I learnt in roughly 10 minutes what I struggled to understand in hours of lectures. Thank you so much! ❤

@savewater2840 4 года назад

It's greatly explained. Thanks for this video

@mannykhan7752 2 года назад

I love this guys " tough love" approach to reaching. Would love him to explain human conception.

@lordepixz6364 6 лет назад

This video was really helpful! thank you

@Taqsunis 7 лет назад

This is absolutely amazing!!! Ty

@andypritchard8017 3 года назад

Wonderful explanation. Thank you!

@unknown-ku4ri 4 года назад

oh its so easy before watching this video every time i thought about this topic my mind was liking bursting Thank you so much.

@barbros2023 10 месяцев назад

Already 2 mins in and I've learnt more than weeks of school. This teacher also doesn't sound boring and monotone. 10/10

@-fish-3316 3 года назад

Very clear explanation! Thank you!

@HoussamBenhallam 7 лет назад

You made my day ! Thank's a lot

@k95channel 7 лет назад

thanks for your helpful explanation!

@Aliens797 7 лет назад

amazing explanation! thank you for the review!

@sheriff5109 6 лет назад

Just take a minute and praise how satisfying the drawing on 4:32 is. Thank you sir.

@DeuceBoots 6 лет назад

"How 'bout the destructive points?...shoooot, you know how to do that. These are gonna be the half wavelengths." Love it. Thanks again Khan.

@saisevithaa1772 6 лет назад

Thanks Sal! Love your vids!

@KashafNaeem. 4 года назад

Thanks this was first video i saw in this chanel and was good not boring

@FelisChow 6 месяцев назад

Thanks for the lecture. Got me to viusalize the phenomenon .

@sharmass3756 8 лет назад

super explanation I got all my doubts cleared excellent

@sarmad1645 Год назад

this is so good im speechless!

@niveyoga3242 6 лет назад

Best explanation I've ever heard!

@raghavpathania016 7 лет назад

Best of luck for tomorrow hueheuheu

@MJ-hq1ie 5 лет назад

Raghav Pathania thanks bro

@hashirkhattak9180 4 года назад

You are the wizard of physics... Damn bro wow... Such an inspiration you are... 🔥... Lots of respect Love you

@made_in_Khaos 8 месяцев назад

Relearning this after half a decade, amazing video!

@MysticMD 9 лет назад

Wow i understand now. Thanks !

@RealEverythingComputers 8 месяцев назад

Thank you so much! This video was very helpful

@shreyajindal3871 6 лет назад

This video was really awesome !

@bhruseantv3461 7 лет назад

it was really helpful...thank u for such a great vedio...

@bettercallbhanu 2 года назад

Best lecture on YDSE on YT. Thank you sir :)

@yoanch0 2 месяца назад

Bro, you have no idea how much this video helped me understand those things

@veerp2865 4 года назад

THANK YOU SOOOOOOOO MUCHHH! THIS HELPED A LOT

@guillaume6373 2 года назад

amazing!! thank you very much

@adamdangelo7644 6 лет назад

You saved my life. Thanks

@virtualgirl7697 4 года назад

Now its very easy to visualise and reason.thanks😊

@sycamour5654 7 лет назад

Thank you! I understand now

@kiranrq9387 5 лет назад

Wow!!!! You are a hero! I just woke up and stressed about how these wave interfere, but you made it like a piece of cake 😊 thank you very much. I still have a question about diffraction. Say the slit gap is exactly same as one wavelength of that particular length. After it is diffracted it spreads out, so does that mean that same wave’s wavelength increases as it moves forward ? And the same amount of waves go through that slit each time? As I have seen water pressure increases through holes. Does pressure make the amount of water flow increase too? Or again it is just as it spreads out it’s wavelength increases? Pleaseeeeeeeee help

@Rubi747HVY 10 месяцев назад

Thanks for clarifying so well.

@premedmelody 3 месяца назад

This just blew my mind

@001khokhar 8 лет назад

Excellent explanation of a very conceptual topic

@Telest0 5 лет назад

I wish I had a teacher like him...

@095-anamaykashyap2 7 лет назад

well explained ... definetly helpful for boards and jee

@martintnguyen0916 6 лет назад

you're the best. love ALL your videos :)

@mugdhorozario4785 4 года назад

Sir , The explanation enhanced my understanding. If I didnt watch this video , I would have lived under a rock with thousands of confusions So sir, I would like to thank you and would encourage you to keep up the good work for us , students.

@fluffzxx9615 3 года назад

Sar, full support sar

@ihaveagoal4665 3 года назад

@@fluffzxx9615 wow how funny, what a subtle racist remark to a student who is just appreciating a teacher for teaching him a concept

@fluffzxx9615 3 года назад

@@ihaveagoal4665 seethe harder

@delusionalplatonist6077 2 года назад

@@fluffzxx9615 you're sooooo funny bro 🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣

@Medusaogre 6 лет назад

Best explanation I've seen.

@_boss_baby_ 3 года назад

Awosome video, Sir can you please make a video on plane wave and circular wave with diagram ,or if possible with some simulation

@gboyawesome1159 4 года назад

Thank you so much I understand it now

@marwaebrahiem7485 4 года назад

Thanks allot for the exaplenation

@ardopalanjian3998 9 лет назад

Excellent. .thank u alot.

@jayashree378 7 лет назад

thanks . very good explanation

@rakinhasan3833 2 года назад

I couldn’t understand this experiment... But now I can understand this.. Thanks khan Academy 🖤

@IsrarKhan-kb9hs Год назад

Really helpful Jazakallah Sir👌

@vamshikrishna323 7 лет назад

Iam a bit confused about this experiment..but with this vid my confusions just got rid off....thank u very much 😃 for uploading this video...

@beyondemotionsvibe2408 2 года назад

Bro, thank GOODNESS YOU EXIST!

@johanchime6063 5 лет назад

thank you so much, helped me understand and I had a laugh with you haha xd

@christianpungo5210 3 года назад

Now that all my college classes are virtual I can finally say (with evidence) youtube is just as good, or better than some teachers. Watching these instead of my prerecorded lectures from now on.

@cmdrriotz5283 5 лет назад

Thanks for explaining this! I am curious...what about the observation part of it? I watched a video talking about when the light was measured/observed during this experiment, it behaves differently than when it's not. Do you know anything about that?

@paryaolfati6451 7 лет назад

wonderful ☺ thanks a lot

@32kirby32 2 года назад

Perfectly done

@DinaHelmy Год назад

Thank you!

@akashneelsaha8300 3 года назад

This is so amazing

@marshchow3093 8 лет назад

thank you very much!

@ahmedabotaleb7584 6 лет назад

could you please make a video about intensity distribution of the pattern ?

@shreyasmiliger1751 4 года назад

I am from India and I love this Please keep continuing this...

@AbdulMajeed-fo9lv 7 лет назад

well explained man....

@GurpreetKaur-rw2ts Год назад

Superb sir pls make more videos related to physics

@nicotean8376 4 года назад

anyone in 2020? 🙋‍♂️🙋‍♀️

@keme_004 4 месяца назад

2024😂✊🏻

@bestmartialartsfightingsce9813 Год назад

Thank you ❤ you are life saver

@pratiksaha2592 5 лет назад

Thank god Sal didn't taught this topic or else I don't think I could have understood so well..............Thank you so much Khan Academy for uploading this video.