Hi, I'm Zor. Welcome to Unisor Education. Today's lecture will be kind of based on many previous lectures. So I would like to use material which we have discussed before and come to some kind of agreement between different formulas, basically. Now, this lecture is part of the course called Physics for Teens. It's presented on Unisor.com. So if you go to Unisor.com, you have to choose this particular course. Now, within the course there is a part which is called waves. And within this part waves you have a chapter about electromagnetic waves. So in this chapter we have, I don't remember how many, like a dozen maybe lectures. This is one of the last lectures in that group of lectures related to the chapter about electromagnetic waves. We were discussing Maxwell equations. We were discussing certain vector operations in this particular chapter. And there are a few particular facts which I would like to bring to this particular lecture and check if they agree with each other. So that's the only thing which is the purpose of this lecture. So I will use material which we were discussing before and I will try to basically check if they agree with each other. Now, the website Unisor.com contains also a prerequisite course called Math for Teens. Now, mathematics is definitely a must for studying physics. In particular, obviously all the calculus is necessary, all these differentials, integrals, etc. Vector algebra is very much used in physics.  Okay, so let's get back to this particular thing. So I would like to remind a few formulas which we have derived before in one of the lectures of the same chapter of the course. Now, the first formula which I would like to remind you is a total energy density of electromagnetic field. Now, energy density means amount of energy in the electromagnetic field which is in a unit of volume, like one cubic meter, for example. So it's related to two vectors, vector E, which is electric component of electromagnetic waves. There is a V, which is magnetic component. This is basically intensity of the electric field and intensity of magnetic field. Now based on these two components of electromagnetic field, we have a formula. I use the letter P with index E plus M, which means electric plus magnetic, and this is energy density. Now obviously energy density is function of time and three coordinates. As well as these vectors, they are functions of time and three coordinates, which means at every point, at every moment in time, it has some value and the value is changing. It oscillates. So electric and magnetic intensities oscillate. Now, so the formula is, and we can just put it on the board, one half epsilon comes E square plus one over mu times D square. Now when I'm saying E square, I basically means E times E, a scalar product, same thing with B. So that's why I just use square, but in theory it's this one. Now, this is the formula for the energy density. Okay, we have derived it in one of the previous lectures. Now the second formula which I would like to remind you is formula which looks like this. So this is the cross product, a vector product of these two vectors, and S is called a pointing vector. Now we basically derived with this expression for pointing vector based on properties of electromagnetic field, Maxwell equations, etc. Again, it's one of the previous lectures. I think it's not the previous one before that I guess. Now in both cases I'm using absolute and middle, which let me just remind you, epsilon is electric permittivity of the medium where electromagnetic fields are propagating, and mu is magnetic permeability, I think. It's called permittivity and permeability. Difficult words. That's the magnetic permeability of the medium where the electromagnetic field is propagating. So it's just basically constants which depend on the environment. There is a special designation for vacuum. It's epsilon zero and mu zero. That's the permittivity and permeability of empty space. So now this is energy density. Now what is this? This is basically a electromagnetic field energy flux. So what is flux? Just to remind you, that's amount of something, whatever the something is, maybe energy, maybe number of molecules, maybe air or water. So it's amount of this something which goes through unit of area in unit of time. And unit of area should be perpendicular to the propagation of that something. So in this case we're talking about energy. So the pointing vector is the energy flux, electromagnetic field energy flux. So amount of energy which goes through a unit of area, in unit of time. So my purpose right now is somehow bring these two together and see if they correspond to each other. Now they obviously should correspond because both of those things are based on Maxwell equations and they have derived them using just plain mass basically. So they must agree with each other. But I would like to basically compare them in some very simple case. So what is my simple case? My simple case is, so let me just wipe out this one. I will put it here. Okay, so what's my simple case? My simple case is flat electromagnetic oscillations. And it's supposed to be one of chromatic. So you have an electromagnetic wave basically, a flat wave which goes along a straight line. And then I can actually compare the energy using this formula in certain amount of volume. And since I have a flux, I can see how much energy is flowing into this particular volume and compare the results. Okay, so first of all, let me just simplify this formula for vacuum. So we are talking about vacuum, so which means I have to put mu0 here and mu0 here. And we are talking about flat wave. What is flat wave? Well, flat wave is E is equal to E0. That's amplitude times sine or cosine whatever you prefer, omega t minus z over c. Okay, now why did I put it this way? Well, I consider that this flat wave has electric component and magnetic component. I assume that electric component is oscillating x, y and z. So electric magnetic is oscillating only along the z, sorry, along the x-axis. Magnetic component is oscillating perpendicularly to it along y. And then the flat wave goes along z-axis. So that's my flat wave. So it just goes this way, up and up. Magnetic, magnetic this way and electric oscillating this way. That's basically kind of very, very simple, the simplest probably way of electromagnetic field. So that's why I put z here. C is the speed of light. So z over c is the time it takes from here to some point z. So it's a time delay until wave comes from the beginning to the point with coordinate z. So in the origin of coordinate it's just plain sine of omega t. But if I'm going into point z, then I have to have this time delay. And same thing I can say about b. b would be exactly the same thing. Now they are always in sync with each other and in phase. So that's why this part is exactly the same. So whenever x goes to a maximum, y goes to the maximum. Electric and magnetic components are synchronized in the same phase. Okay, so these are two equations which describe my oscillations at any point on the z-axis. Okay, and it's a flat wave which means the whole area x, y actually is going in sync with one particular ray along the x and y is equal to zero. So that's what it means flat wave. Alright, now in this particular case let me remind you another formula which we have derived before. We were talking about amplitudes of electric and magnetic components and we came up with the formula b0 is equal to e0 divided by c. Now that was again one of the previous lectures and based on this I can replace this with e0 divided by c. Now using these expressions for electric and magnetic components I'll just simplify my equation for the power, I mean for energy density. One-half epsilon zero e square plus one over mu zero and instead of b square I will put, instead of b square I will put e square and I will divide it by c. Square, c square, right? So since my e and b are related this way b square is just equal to e square divided by c square. Okay, now let me just remind you another formula which was derived again. It's all in the lectures of the same chapter about electromagnetic waves. Speed of light, square field of light is equal to, that was a consequence from Maxwell equations. Okay, which means that one over c square is equal to epsilon mu. So mu and mu, so instead of this, instead of c square in the denominator I can put epsilon zero mu zero, mu is going down and the whole thing is equal to basically epsilon zero e square. Very simple. So this is the energy density of electromagnetic waves. In case we have this type of a flat electromagnetic field oscillations. Simple, right? It depends only basically on the electric component because magnetic component is very much related to electric component. So that's a simple thing. So I know the energy density. Okay, so let's assume that I have a space, a piece of space and electromagnetic waves are, light is propagating this way. It's in vacuum, so it's light, I'm talking about light which is electromagnetic waves, so it propagates this way. I want to know how much energy is flowing into this area during the time of one second considering this area is equal to one square meter. So why am I doing this? Well, this thing is the flux. What is the flux? It's amount of substance which goes through the unit of area which is one square meter during unit of time, one second. So if this is the light and the light is moving into this parallel, if you wish. So this side is one square meter. Now in one second considering the light is propagating with the speed C I will have obviously C meters, right? In one second. So this is one square meter, this is C meters. That's the length of this parallel pipette. So the volume is equal to C, length times the area. Okay, if the volume is C, if I will multiply it by density I will have amount of energy flowing into this parallel pipette during one second through the area of one square meter. Now I'm supposed to basically have the same thing if this pointing vector is expressing basically the same thing, a flux which means how much energy in this particular case is flowing perpendicularly to one square meter in one second. So let me just check if I will have this thing corresponding to this thing. Well, that's very easy to check. Since we are talking about two vectors which are propagating this, is oscillating along the x-axis and this oscillating along the y-axis perpendicular to each other, then I can say that absolute module if you wish of this particular vector is equal to one over mu square times E times B, right? Now B as we have already discussed is equal to E over C. So what's the result? Mu zero is equal to mu zero is equal to one over C square, am I right? Yes. So one over mu is equal to epsilon zero C square. Now C and C square goes out and what do I have? Epsilon C and E square. So I'm not surprised that they coincide. They're supposed to basically be equal to each other because these are things which we have derived from the same Maxwell equations. But nevertheless it's always nice to basically come to the same thing from two different roots and the same thing is supposed to be equal if the roots are correct. So for this particular case when you have flat waves, the simplest case, it actually gives you a nice kind of feeling that, okay, we are still in logically correct way of researching this particular problem. So basically that's all I wanted to present to you. So what's important is this expression for pointing vector which is basically the vector which gives you the flux of electromagnetic energy which means amount of energy which is flowing through the unit of area perpendicularly to it during the unit of time. That's basically what I have described as this parallel pipette. And it corresponds basically to my main formula about energy density of electromagnetic field which again we have derived before that differently. Okay, now I do recommend you to read notes for this and every other lecture on Unisor.com. And actually if you found this lecture somewhere else, not on the Unisor.com, still it's much better if you go to this website because every lecture has textual description right next to it. Plus lecture is part of the course. As you see here I'm referring to previous lectures where I have already derived certain formulas and if you would like to be comfortable with this you have to really go to these lectures as well. So it goes without saying that to take the course is much more important than if you accidentally hit the lecture because you will not really understand where the formulas are coming from. Unless again you go back and research etc. etc.  Okay, and also I have to mention that the website is totally free. There are no advertisements, no strings attached. You don't even have to sign in if you're doing just basically self-educating yourself. You do need to sign in if you would like to work under the supervision of somebody else like your parents or teachers. And then the teachers can basically assign you a particular piece of the course maybe to study. Also the website in many places, not in all places but in many places it contains exercises, problem solving and exams which I do recommend you to take. There are no restrictions. You can take it as many times as you want. Okay, that's it for today. Thank you very much and good luck.


This is most feared just dropped this is the earliest most feared has ever dropped in my like seven or eight year history of playing Madden and honestly look sick. I love a lot of the cards. I'm so pumped to figure out what exactly they have I never ever ever spoiled promos for myself. I don't go on Twitter and figure out all the best this into that I just want to figure out by opening packs what cards exist in the most feared promo There's a most feared bundle that has 20 of the packs and a guaranteed at 290 overall most feared players The only thing I think is I don't think there's a DK mat cap yet Or if there is it just hasn't come out yet because I feel like I would have gotten DM'd a bunch about wheel of mud And I'm actually really sad because I was really praying for a DK mat cap But it is what it is. There's also a training store pack 5,500 for 90 overall most feared player regardless I'm gonna do the most feared bundle. We're gonna get gameplay with somebody sick today The bad news the reason I tell you this and the reason I'm actually getting this video out I thought for sure they weren't gonna drop most feared for like a week from today like They dropped it on the 15th. I recorded like three wheel of muds Yesterday, so none of the most feared content is in it. Not that I necessarily would have gotten most feared players and wheel of mud It doesn't really ruin anything yet because I don't think there's a DK mat cap prestige Nor is there a Darren Waller prestige and Jaylen Ramsey just got a card So that's not the issue. The issue was I just want to make sure I'm the most updated content for you guys So I just want to let you know you won't see most feared stuff the next few little months. I apologize All right 20 times most feared bundle.   Okay, so the elites also get that animation.  I'll take a double most feared Tyler Davidson and Salman Kinley I wonder if they're still gonna do like scary strong scary fast all that shit They might it might already be in the game from I know JK Scott. Hey, I'll take it I assume there's sets to get like the really good 92 plus overall players So first comes to words we can try and complete what I just got 87. Damn. There's a chance. I just skipped a really good animation I got a slow down Jerry Hughes Jerry Hughes again. I was I mean that's nice. I'm getting elites. I guess I'll be all right We do have a lot of these backs and the topper. Yo, and as you're watching this video I'm in Bloomington, Indiana watching MSU versus Indiana In fact as you're watching this video the game might have already ended because you're seeing this at 8 o'clock Eastern on Saturday, so the game already ended so hopefully Sparty should be 7-0 right now If we lost Indiana, and I went all the way to Indiana for the game. I'm gonna cry. Give me that Give me that new animation.  Hey, I got no Kevin Green Okay, that's just extra. Oh My god Justin Tucker and Kevin dude getting Justin Tucker is actually so sick I think he's worth more because of his team of the week I think if you want to power him up, although I guess I don't know if the kicker has a power-up I don't know. I'm sure he's worth a lot anyway. It's one of the best kickers in the game regardless my hues Damn, that is kind of clutch. It kind of gives me a depression thinking about Justin Tucker now Alex Lewis a bunch of bombs dude. Give me the new Oh This card is gonna be so cracked, bro. Is he gonna have like 91 speed?   I've been talking about this a lot I'm sorry I repeat stuff, but you don't need a skateboardist this year 81 speed as fast as hell Wow, he gets three slots.  He doesn't need it. He need 97 overall But he doesn't need it because he's a field general.  He doesn't get past the lead I heard that's really good.  I know he definitely gets inside stuff, but I might not give him a bill Jonathan Allen, let's go. So you you need 390 overall heroes to get ed read his power up same with Larry Allen Jesse Bates Derek You can get vanderash by adding two eighty sevens and three eighty-fives. Did we get that? We might have made that work.  Although. I think I'd most likely want Lane vander as Lane vander I should probably a savage. I actually want to use that Derek Henry You know what? I'll bless you guys with the Derek Henry right now I do want to probably give him his own video, but for now we'll just hit it back and play bruiser backs I swear to God bruiser backs are better than a lucid backs this year We're just crazy because it's never been like that. It's always been jukebox fast backs or OP But this year for some reason truck is just way too good a 92 bro. Derek Henry with wait.  Let's go. Card art looks nasty, too. I respect it. All right Oh, let's go down this line open. I'm ready to play Derek Carr. Oh, it's too Derek's. I didn't think about that And I know you see the crispy red in my ears huge Thank you to Raycon for sponsoring today's video. You guys are so used to me wearing the blue Raycons I thought I'd switch it up. You know, it's like a fall color. I want the red.  These are crispy, bro The case is dope too. Don't worry. So if you're not clued in Raycon makes premium wireless earbuds in my ear right now Is the everyday earbuds these things pack a punch? They're awesome and they come in at about half the price of other premium wireless earbuds That's definitely my favorite part now for some specifics the gel tips are optimized to fit in your ear I've used tons of earbuds. They fall out a lot Raycons do not love that It's really amazing for the gym. Honestly eight hours of playtime in a 32 hour battery life There's a built-in mic so you can take calls and they're so confident how good these are There's a 45 day happiness guarantee. You don't love them. You can send them back But I know if you get Raycons, they're gonna love them So you won't have to worry about it if you need new earbuds I highly recommend you check out Raycon like the link in the top description or go to buy raycon.com forward slash MMG to get 15% off your Raycon purchase Raycon. Thank you for sponsoring guys. Enjoy the rest of the video Julio Jack Youngblood and Zach Wilson versus our top three. It's gotta have Derek County on it. Let's go Oh, that's so sick. Oh, and this is actually a house rules called out of options, which I will get more game plan later It's definitely gonna get its own video plays go on cooldown, which I love This is so you can't just spam the same place over and over and over. Oh, are you there baby? He's there Let's go. Who is this? Is that AJ Brown? I think it's AJ Brown.  Whoa See what I mean like that's 82 overall Mike is taking he just still plows through anybody.  It's not there. Canary.  We have to make sure we adjust that But you know what he's gonna get it because the floodgates were open right there I form stretch to Derek Henry. We have bulldozer reach for it and back. I can't wait to use back I That literally wasn't even a truck animation.   That was Way too easy. All right. There he goes, baby. All right. Good stop. Let's get a stop, baby We need this middle's not open underneath not open. Whoa. Why did he get open? I thought he was it?  Yeah, we're letting him on He is two o'clock almost want to let him score here. I do have to time out so he can can only chew this so much Solid stop. We got a time out off. Good tackle. Good tackle. Am I hurting myself by tackling him? I almost sure let him score, huh? It's right up the middle and he's right in but okay He scored instantly it would have been bad if he hadn't scored and then scored And we are just gonna send Derek Henry up just in case. Let's see if we can hit Derek Ken or Darren Waller Darren Waller, yes sir. Great ball. Hey perfect pass accuracy outside the numbers, baby Wait, no get out. Oh, he stays on his feet and gets out of bounds like a sticky. Oh my god That was so clutch. We needed that so bad Shit 17 seconds on the clock. It's now fourth down. I have to get out of bounds This is my go-to-play if we're dating at Tomlinson gets open. We're actually gonna get this money If he doesn't know wait, what he was open. Why did he throw it so haywire? Hey, it was a great game though. GG to my opponent. That was a fun one. Derek are just sold, bro He's probably looking at the Gruden emails He was frantic they're trying to delete his own emails because he knows they're about to get gone through I mean, you're not wrong, but you didn't have to say it All right, let's run it back, baby Unfortunately, Lydana Thompson. I think he's my like passing half back right now or something. Just got to throw a bomb Oh, it's the dairy part of their waller connection. Oh I didn't even piece together until just now that that's who it was and you know what going for two last time lost me the game So I think if anything this time, it's gonna win me. Does that logic make sense? Absolutely not Second and 17. He's gonna throw a pic Let's go Haynes Mike Haynes pass it or fair. Oh, yeah, it's legal.  All right. Hey, let's give it back to Derek Henry I love this Derek Henry. We got to run somebody over That is so lame. He was user delining on that side. Oh, oh, no, no, you have to go left side Me nobody talked to me. Don't we say anything about what's happened? All right, I'm literally gonna march Derek Henry down this field. I will not do anything but run the ball That's more that's more like it. Go ahead and pitch it down. I'll get I'll kick it to the outside.  They're nasty again off these blocks. I wanted to still get him the fake to Darren waller Well, it will it move his user Absolutely moved his user it moved his user out of the middle of the field and in no lie He's really keying on Derek Henry doing a good job at it Jesus I second attempt we're just going right up the gut and we're We're tired. I do have to pass that dude.  No way. He guards this no sir Wait, stop and go. No, I'm such a dickhead I will say the Derek Carr to Darren waller connection is real solid right now. All right We're gonna try the edge of Derek Henry. He's been locked in animation. So I've never seen that animation before You have to quit. Why are you playing right now?  He literally cursed score touch Ooh That was super Nowhere to oh that I said nowhere to throw. Oh, he just followed me. I could lose wait I could lose wait I could lose What am I doing? I kind of I kind of low key hope I lose. I hope I lose so I learned my lesson. I Can't You have to be the worst decision you could have made you had a chance in the end zone, bro Oh, just threw a slant Well, a win is a win the history books will only remember that I got a win today They will not remember how I almost falcon if I can get him in the backfield here on this run play Presumably a run play feel really good. Who's just kicker Mason Crosby?  I love you boys yay. I hope you get chlamydia from Venus guy. That's what I think yay Whoa, whoa


here's and I hope you can hear loose and we haven't we haven't rehearsed this so you're going to get a double act I haven't rehearsed but normally we're quite a good double act so I'm I'm you know then tell them that we've rehearsed this tons this is going to be very professional well here here we go what I'm going to do is this is very much for an international audience we work in a large further education college which is like a community college in in the states or a TAFE college in in in Australia we do a lot of further and higher education and what we're going to tell you really is a is a tale of a great development we did and we won we actually won from a one-in competition with a whole lot of universities and things and we really took quite a simple approach and we're just going to show you that and give you a walk around the website and the resources and things that we built as a link there you can go you'll get that later and that just that's just giving you some more background about about about about me so in December last in 2018 we won we won a government tender from Skills Development Scotland in the Scottish Government and that was to create a skills portable portal for the National Manufacturing Institute of Scotland and I'll show you a bit about that later it's meant to be a distributed centre to train people in higher education and colleges and we want the bid on the basis we're going to take a very different approach we'll build a website or we'll use our VLE or we'll do all of the things that would have made it hard to sustain at the end of the project so we took an approach that wasn't about server space it wasn't about lots of development time it wasn't about ongoing hosting charges and all of the other traditional charges all the other traditional challenges okay and we really did this because we had a conversation with Google and we had a conversation with Google that went along the lines of if we were a big educational institution you would give us Google education for free wouldn't you and the answer was yes so if we were a partnership if we were a partnership of educational institutions that wanted to share things would you give us a Google education account for that partnership and the answer was yes and that got us really going so we could use Google sites unlimited band unlimited storage space behind it all of the Google tools and it gave us a sharing platform that was out with the baliwick of a single institution and it also means at the end with a bit of careful jiggery pokery on how we set the domain up and how we communicate with the people that have joined the community that we can we can hand the community over as we're going to do to the National Manufacturing Institute for Scotland at the end of the project and they get a whole lot of resources and they get an on they get a ready built community so that's what we did behind the scenes but what we did to justify what we were doing was we wrote a paper that identified we wrote a paper that identified the digital skill frameworks for colleges and for universities and for work-based learning what what had been identified is they could build a centre but lectures in universities and colleges and in the workplace don't have the digital skills to share things so this was all about building building digital skills to share stuff we identified five interventions we already had we already had a professional development award in the college so we took these materials and we repurposed them and we made them open materials we pushed them out the way and we delivered it all through a series of webinars and teach me so webinars and face-to-face and importantly we used technology that everybody could access so we used zoom meeting google google slides all the tools that were open and flexible so that not only were we giving things away we were also creating a model that was sustainable that other people could pick up no matter where they were the deliverables we delivered them all 50 ambassadors 200 staff engaged across scotland we actually blew the lid off that five strategic interventions a library of assets to support digital skills and with that focus around stem and manufacturing 4.0 and we delivered a program of 50 webinars and free face-to-face events to engage staff the progress was quite steady we identified all stakeholders we delivered it all in time there was a bit of an extension because while we were doing this the the further education colleges in scotland went on strike so we were meant to have it all delivered by september and we stretched the delivery up to december 2019 so there was a week there was a wee hiatus because we couldn't do teach meets or run webinars when everybody was on on on strike so that was that was the original timeline and eventually it was stretched out to december 2019 what i'm going to do this this really tells that story again about the initial paper and what we agreed to do i'm going to show you in a minute what we've done we're now handing over to stratclyde university and the aimis team now it's all been formed and what we're doing in the background what we're doing in the background is we're repurposing the assets because all the assets are open we know that other colleagues across the further education sector particularly now that we've all gone to working remotely when you see the assets you'll see why they're relevant they're all busy repurposing these assets so they can use them within their own within their own training or within their own colleges okay and in the background that's been really useful and i think we also can incur we've really done a lot of learning about how to use zoom how to deliver webinars and how to actually almost more importantly than doing a zoom webinar how to curate them because what we discovered is that lots of people don't come into the webinar but they do pick up they do pick up some of the videos and some of the assets later and on the back of this this model that we've used we're actually getting lots and lots of other contracts with lots of other organizations in the public sector educational partnerships that actually want to take this approach to they want they want a quick and easy google site and they also want that bit at the back end where they can store they can store and share lots of assets and and they can collaborate round a round round a round a google site now i'm going to disappear luce can you share your screen or will i share my screen i'll help do it for mine i should hope that this should work i just need to start my entire share hopefully this should be sharing now if i go whoa let's get rid of that infinite there you want to talk to the site yeah so it was all kind of built resources in google sites as the kind of front page to store the materials present with people that most of the materials are actually sat as either google slides or videos so they're all kind of transportable so as this happened in the last week or so nma s has started to gear up to move things to their own website so we used to have a lovely url up here so ignore this ugly site url which was nmis-skills.org so that now redirects to their site as they get ready to move things over but we'll share this url so you can see this and get access to it but basically we've got blurbs about what the actual project is this was all mandated to us by effectively the scottish government of what that has to be on this front page but we've got lots of useful things the main core of what we were kind of offering people was our program of study effectively which is split into several different sessions and topics so digital learning design we established as one of the early topics we wanted to cover because you can't really do digital learning unless you know about the kind of background knowledge behind that how you should be actually designing your learning to act you can't just port your lectures into a webinar and you're done um so there's some theory that needs to go in there um online assessment which is a big hot topic at the moment obviously as everyone's trying to figure out how they can assess their students have that in there as well collaboration so using collaborative documents again i don't know how good your institutions are on that but a lot of the people in our institutions and other ones in scotland just aren't used to doing any of this kind of online collaboration they're so used to saving the word document sending someone an email they edit it and then send it back so really covering some of those fundamentals there for people of how to use a collaborative document such as a google doc or office 365 webinars and screencasting pretty self-explanatory using youtube again a lot of people aren't familiar with the fact that you can just grab some youtube videos or if any video site and use that in your learning by turning them to interactive videos with other tools a lot of people think of video is that i'm going to have to go out there make my own videos um you know record it edit it we wanted to kind of get rid of it i don't get rid of but move away from that idea and show people no there's tons of video content out there you just need to find it and use it and we also did a lot on um digital well-being as well which is another topic that's coming up more and more um of so the kind of ideas of the the attention economy uh having those notifications all the time and distracting you so kind of give people information on that so a different to digital learning design i can show you what our actual resources look like so we have recordings of our webinar that links through to our youtube channel which i'll just open to show you quite briefly and then hit pause before i annoy everyone so we put it all on youtube so it's all easily available for whoops so it's all easily available for everyone we also have got obviously hard copies of all these videos so that we can move them across to other sites as well when required we've got a slide deck which is what our videos are presented from these are all just saved as google slides because it's nice and easy for people to access them they can download them they can look through them uh they're all kind of a very clean and crisp design um so that's easy for people to to use we also baked in things to them like these teaching challenges which is one of our ideas so instead of just presenting people information we want to give them a little challenges to get them to go out there and just try something so in this case it was to try and get people to go and use a tool called learning designer where they can um create their lesson designs and see uh how that figures compared to um the abc learning design which might be something probably don't have real time to go into that right now but um we'd also created um forums which was just using a google group they didn't get as much traction as we had hoped uh joe can talk to me or a bit about that in a second once i've finished doing this tour um with helping our community to build and helping them to give so much talk but that didn't really happen in that particular instance we also uh created playlists of videos from youtube on the topic so again this idea of not reinventing the wheel grabbing what's out there and highlighting it to people so they can reuse it and then we'd have a selection of resources based on the topic so again linking people out to other places where they can find information so things like the mit open course where a great resource that a lot of people aren't aware of at a lecturing level um and then further resources where we really go down into the nitty gritty and you can find what they want and all this is then backed up by we've got uh full academic references as well for people who wanted to kind of uh dig into some of the things where we've got some like our learning design pedagogy from and all like this um one of the other key parts of it was getting people to sign up to our community in the form of ambassadors which we just created a very simple um form for them to sign up they we would then create an account on our g-suite for them so they could then um share stuff between each other and more securely Joe do you want to talk more about the ambassador side of things yeah yeah of course so again back to i told you about that industrial action and that slowed the the whole process so we're at the stage now with ambassadors we're moving that bit forward with straggling university and NMIS so we've got a we've got a we've got more money which is great to extend our work uh the idea with the ambassadors we were going to reach out a very large number of staff which which which we did mainly stem and engineering staff across across all of the colleges and the universities but the ambassadors were going to have a special VIP offer and that special that special VIP offer i'll jump over and i'll share the screen now as well that that that VIP offer was to give them access to the back end of the the google site so that they could they could upload and they could share resources and we haven't quite got to that but we've got lots of people who are keen to do it but nobody quite done it yet so we're just at that stage where we've engaged the audience and we're just about to start doing that last bit and i'll just i'll just try and share what what we've got at the back end give me a second well joe's getting that up we also organise quite a lot of uh teach meets in three different cities in in scotland edinburgh glasgo and avardine which we had quite a lot of um uptake for and people were really keen to get involved and meet people from different institutions and find a way of collaborating because it's just it's not an easy thing for them to do because they're all stuck in their own institutional version of moodle or you know office 365 where a lot of them are locked down and they can't share even a simple document with each other if it's you know bigger than their email sizes you want me to share or do you have any trouble there hold on yeah i think i'm having trouble i'm not getting into the back end just now sorry i thought i had a women application window hold on no i'm not loose can you have a quick go at it yeah i'll share it i'll talk you through so the original intention was that we were going to make all of the resources open and we were and again this is just quite interesting we worked in partnership with ember with a university as well around giving people a high level slide deck around the changes that are happening with industry 4.0 so we've got all of that and we've got that as an offer for the ambassadors and the ambassadors have been downloading it but not uploading things but ember university did ember university although their champions have opened they were worried about making the slides open and i'm guessing i'm guessing because you know again it's that bit of teaching and learning there are some images and some things that using your teaching and learning that you can't really put in the open web so i'm guessing there's some bits and pieces in here some diagrams some other other stuff that's okay for the educational community but can't go on the open open web but what we're encouraging people to do is to do is we've done a and check all your images and all your all your resources so you can put them out in the open web you know as as luce is sweeping through that i'm guessing perhaps that map and some of the other things might might not be on the on the open on the open web so that's why they're they're kind of restricted to that educational community you know we have also set up so that's really sorry joe go ahead no i'm just gonna say so these are all done through just shared drives in google where basically when someone signs up as an ambassador we give them an account on our g-suite so it's kind of a walled garden you can kind of think of it as and then i add them to an ambassadors group and then we can share these drives with all of the ambassadors we do have a file sharing area i won't go into that because i don't know if there's anything there the ambassadors only want to share with each other and don't want shown to a wider community so i just want to open that up just for data security reasons but you know these are kind of resources that i could show easily so they do have an area where they can upload files and try and share them through that way and it's kind of it's almost like that idea of baby steps really we're dealing with people who haven't really done any full online collaboration before and we're trying to make it as simple and easy for them to work cross-institutionally and be able to share anything at all really so it's kind of yeah one step at a time trying to take it slow with them so we are hoping to have well we were going to be having more teach meets and stuff before this whole crisis hit where we do more in-person things with them so we can get them used to it and then introduce these tools to them and get them working more online but again it is uh dealing with skill a very very varied skill level of um ambassadors yeah i mean again we're coming up to a few minutes left joe okay just last bit i mean again just to reiterate we're we're dealing we're dealing with with colleagues who aren't that confident about you know if you look at the kind of the the main interventions in nmis about doing digital assessment or or webinars and put things online all of these things they're just not often with these kind of things and where they do share things they they say things like oh i shared it i put it into our vle and you're thinking well that's only sharing with your institution so we're giving them skills and we're also giving them a platform giving them a place where they can really share things with the community and they can share things in the open space uh or if you're worried about sharing the open space they can become an ambassador and just share it with their peers in the in that closed space and and that's really the story of any any nmis uh and the the big centre is actually being built just now as we speak out near Glasgow airport but the ambition is well it's a physical space it's this distributed learning space and that's what we've been supporting and what we're fortunate in is we've got more money to continue supporting it and and this model that we've created a model that other other educational bodies has been interested in adopting too so we're likely to do some other projects we've got one just now that luce and i are working on with the construction industry that's following quite quite a similar model and thank you luce do you want to say anything else no just thanks for coming along oh that's that was really great thanks guys sorry i hate having to do this


Hi, everybody. Thanks to be here for this talk about chopping the monolith. I'm Nicolas Frankel. Well, nobody cares anyway. Just to be on the safe side, I do this talk in multiple countries. In some countries, it can be considered offensive to contradict the attendees. I'm sure here it's not the case, but if at any point you feel offended by my opinions that contradict your core beliefs, just leave at the moment and don't hold it against me. So that being said, we live in interesting times where if you are doing microservices by default, you are a good developer.  Who here is a good developer? Good. So you are doing microservices, right? I know, hey, come on. That's the assumption. Who here is doing microservices?  I want to see everything. OK, half the room. That's an interesting take. So we live in an industry where we are supposed to be engineers, but we mostly live by hype. Microservice is good, monolith bad. You might see that I have a bit of gray hair, which means that I'm probably either old or experienced or both. I would like to think that I am experienced. And I want in this talk to perhaps challenge some of those beliefs and offer some ways that you can do otherwise. So just to get back on the initial microservices stuff, I won't read it to you, but basically this is the definition of microservices by Martin Fuller. So if you have anything against this definition, you bring it to Martin, not to me. That's not my problem. This, I consider the truth. If you are not happy, well, go back to him. Again, in the same article, he describes several characteristics of microservices, right? And in general, here, cool, right? You know, just once I did this presentation internally, not this presentation, but a presentation, and I thought that was a very cool demo.  Not at all. They didn't care about the demo. They care about the stuff. This is $100. Anybody can buy it. Anyway, so the microservices stuff, well, componentization of your services, everybody does it. That's basically the definition. Organize the run business capabilities, blah, blah, blah, blah, products, not projects. Among the people who are doing microservices or said they were doing microservices, who is organized around products, which means you have a star date, and you have a recurring budget over the years. You have no end date to the project, at least at the beginning. At some point, it might stop. Whereas a project has a star date, end and end date, and a budget over the project, and probably over budget after some time. But that's normal. So who here is organized around products? OK, like 10 hands, at most. Yeah, because you have two hands. Good. And so you see that people were saying they were doing microservices. According to this position, they are not really doing microservices. They pretend they are doing microservices because they have some of the characteristics, but not all of them. Now, if we get even further, I remember when this microservices trend started, like everybody was talking about Conway's law. The people who advertised for microservices said, you must reverse Conway's law. Who is not familiar with Conway's law? OK, so the idea is in the thesis by Melvin Conway that your architecture mimics the communication channels of your company, of your organization. That's his thesis. And yeah, I was happy to meet him. Come on, I need to brag a bit. And so because we are organized like this, so we have front-end engineers, we have middleware engineers, and we have database administrators, then we have a layer architecture. So if we want to do microservices, we need to use Conway's law. So if we want this architecture, we need to have self-contained autonomous teams. So I will ask the question again. And I have nothing against you. Who here is organized and who is doing microservices is organized like the diagram on the right? Not the half-half. In general, it doesn't go in your direction if it's half-half. But anyway, OK, still 10 hands, but not the same who were organized around products, which is interesting. And the poster child for this organization is Amazon Web Services. They popularized the idea of two-pizza's team. Well, the side of the pizza depends on which country. If I belong to the team, that's different. But basically, they are like small self-contained autonomous teams. So the idea is you want to go from the organization on the left, which is probably your legacy organization to the organization on the right. And for that, you need this person. So now the question is, who is this person? Who I want to illustrate with this picture? Who? Banana man. Banana man.  I don't think you have many banana men in your organization at the moment. So that's the wrong answer. But that's a funny one. Anyway. Markies. Among keys. Yes. OK. You are now responsible for the real answer, which is middle managers. Is there any monkey in the room who belongs to the definition? And now everybody is super afraid, right? No. On a more serious note, yes, if you want to move your organization into a certain direction, you need the help of middle managers. Of course, you need to have the willing and the backing of the executives, but nothing will happen if you don't have the help of the middle managers. Never works. And now comes the $1,000 question at the head. In this group is a middle manager. In this group as well. In this group as well. Where are the middle managers here? They become engineers, I'm not sure. Another answer would be pitchy. But actually, it's that the problem. You want the help of people to help you make themselves completely useless. Because even if on the organization on the right, you might need some middle managers. I mean, the basic idea of autonomous self-contained team is there is no manager. And if I might have, you might think that, again, something against the managers, I have something against the bad managers. And bad managers' main task is to accept my vacation requests to be the proxy of my raise every year when I have one. And when I mean the proxy is you cannot negotiate, right? Hey, you've got x%, thank you, or oh, I'm super unhappy. But whatever happens is just a proxy. And do some reporting. This is what bad managers do. I have a couple of good managers who helped me achieve my job. They were really supportive. But in 20 years, five, perhaps four. So that's the problem. So I believe that it's very, very hard if you have a legacy organization to do microservices. What you might achieve is you will have technical microservices and still your regular organization, which means you have none of the benefits of microservices and all of the problems. Congrats. Now, how does it work in real life? Well, you have one senior architect, someone who is very technical. He reads about microservices in a magazine. He said, wow, that looks cool. We can solve all our problems. He has some influence in the organization, talks to the chief executive officer, talks to the other executives. He got buy-in.  As I mentioned, you've got none of the benefits. Then he quits. Who is going to maintain the microservices architecture? Because you call them monkeys, right? So the people who are left need to maintain that pile of crap. But at least the guy has all the women, because everybody needs to be represented as microservices on their resume. Full win for them, full loss for you. But the question is, why are we so obsessed with microservices? I mean, there must be a reason somehow. So in another article, a follower lists three main benefits of microservices architecture. The first is strong module boundaries. The second is technology diversity. And the third is independent deployment. So let's see if any of them is reason enough to move to microservices. First one, strong module boundaries. Yes, you have completely separate repositories, unless you have a mono repo. And then I never understood why you can have microservices and mono repo. But let's forget about that problem. So you don't have related code base. Of course, you have no dependencies between them. This is strong module boundaries, right? Yes, this is, however, a small benefit for a huge, huge investment. There are other ways to get strong module boundaries. For example, if you are in the GVM, you can have your modules, your, like, GPMS modules. You can have, like, static checks with Sonor that says that this package cannot call this package. There are other ways to achieve that. This is not reason enough.  It will work, sure. But not sure it's the only way, and it has a strong side effect. Technology diversity. Everybody loves diversity. We are in IT. We must be diverse. And so technology diversity is saying, hey, we are a Java shop, but I love Rust. What? I love Rust. I also love Kotlin, but Rust is a better example. So I love Rust. I want to learn Rust. And though we are a Java company, my next microservice will be in Rust. And it's good because it's diverse, right? And now I leave the company.  Thanks to be seated on the first row. I have stickers for you afterwards for your pain. I really appreciate that.  I mean, even if you are the Java shop, it's very hard to recruit a good Java developer. Imagine recruiting a Rust developer if you have no clue about Rust. No great idea. So the only thing that I have is independent deployment. So this is like projects, and you have like free main phases, specification, implementation, and deployment. So this is outside our scope, the specification. Mainly it's communication between the business and us. It's incompressible. However, what we can work on is implementation and employment. And this is like known as the lead time. So the idea of deploying often is not a new problem. We already had this problem before. But before, we did it in a very different way. Before, we had really strains. So we deployed, let's say, four times in the year. It's not funny. You're probably using right now software that we deployed like this. And the idea is that it's very hard to test the whole monolith. So we cannot test it completely all the time. So we need to reduce the number of deployments again to x time, let's say, four times a year. The thing is, the business needs to wait three months to get their feature. But who here is a developer? They're not only everybody. We are always late, right? Come on. We are always late. So if you miss the train, they need to wait three months extra. Business is never happy to wait three more months. So what do we do? Well, we cannot deploy. But there is a trick. You can still deploy if it's a bug fix. It's not a problem. You just ship the unfinished feature. And of course, now there is a bug. And you can continue working on the feature. Drinks the bell, right? I know.  We find a way to go around the rule. But this is based on an assumption that it's not possible to test the monolith well if you release often. And the assumption that the microservices people tell is that they never tell it. It's not possible to test the monolith well. The underlying assumption is that it's, of course, very easy to test the microservice well, meaning that the microservices is completely self-contained, has no dependency to others. There will be no side effect, whatever. Of course, there will be less ripple effects, unless you have a mono ripple, blah, blah, blah. But still, the assumption is completely crap. You have hard contracts, yes. But I'm pretty sure that there is some implementation detail that leaked. And then you can break something if you just test the microservice. So in my opinion, the real problem is we think of the monolith as a monolith. However, if you have worked for some months or even some years on a code base, you may have noticed that some ports change very frequently or very randomly. And some other ports are very stable and very rarely change. Do you also have the same experience? I mean, the only one. Yeah, OK. So my experience is that, in general, it's the business requirements that makes the change or a change in law. So business requirements, frequent, low, random. We already had this problem at the time when I was young and a young engineer eager to develop my stuff. How did we handle it? We used the rules engine. Who knows about rules engine? Oh, not that many people. Who doesn't know about rules engine? OK, and then some people are shredding us cat. They are between knowing and not knowing. OK, that's interesting. OK, so for those who don't know, the idea of a rules engine was you would deploy once the engine, and then inside, you would deploy code on the fly. And this code would get evaluated by the rules engine, blah, blah, blah. And there were a couple of benefits. The benefit is that the business would be independent of the release cycle. They could go to production, make directly their change, and it would be applied immediately, which can create issues because sometimes the dates, you need to apply the change at the correct date, especially with law, blah, blah, blah. I mean, I don't want to work on the detail because this talk is not about a rules engine, but the idea would be that. And so some businesses would be very afraid to rely on IT, depending on the organization. And they would say, we want a rules engine, and then we want nearly all the code there. The problem with this approach is that, well, IT would be very happy because then it becomes their problem, not yours. But the problem with this approach is the idea of the business changing a rule is crazy. I never worked on such a project, but I asked one of my colleague once, hey, show me the code. But how does the rule looks like? And wow. So first, I don't believe any regular business person could have changed it. You need to be a developer to understand the rule. And then you need to be also very familiar with the business. So the idea of being independent is an idea, but it's not a reality. Anyway, this is only one of the ways. My idea is if you isolate the quick changing part or parts, you can replace it with a single microservice, with a serverless function, with a rules engine, with whatever something that is not invented yet, and keep your monolith working. Do you know this microservices pattern by Chris Richardson's book? Do you know the book? OK, very, very interesting book, like this thick. I read halfway through the other book. He does everything by the book. And then halfway, I understood that nobody is crazy enough to implement everything. So about halfway through the book, I just put it back on the chef's table. If you want to do microservices the real way, you should read the book and implement everything. It's a lot of effort. Anyway, there is a companion site, which is also very interesting. And in one of them, he talks about strengthening the monolith. So basically, there is this like Martin's folder design pattern, strengthening pattern. And the idea in strengthening the monolith is very similar. So basically, you start with a monolith, then you chop one part, which becomes a microservice, then several more parts and parts and parts. And at some point, you don't have the monolith anymore. You only have microservices. And this is a very good idea. But his idea is this is to be architecture. Everything is microservices. That's the grail. Everything is nice. We have achieved microservices' paradise. Whereas my idea is why don't you stop there? So here, you just have the quick-changing parts, and you keep everything in the monolith, which is very stable anyway, so you don't care. So one way to achieve that is to use an API getaway if you are in a web environment. So you can like, through the monolith, you send everything to the monolith and at one point, you just change the routes to one function that is serverless, microservice, a rules engine, whatever, I don't care. The best example I have is like, I've worked in e-commerce, is the pricing. Who has worked in e-commerce as well? Yeah.  And the pricing is the crazy sport. Yeah, there you go. I didn't work on taxation so much, but the pricing was always crazy. Like, the business always had crazy idea. Like, the regular stuff like, okay, you buy this product, and if you buy X, you get, let's say, 10% is easy. Then they come with, oh, if you buy X of this product, you can get Y for free, okay? And then they come, yeah, but if you buy Z of this product, then you get no shipping costs. So every time you wanted to do something, they had more crazy idea. I worked on the hybrid platform that was impossible. So my idea is we can chop the pricing engine and do something fun. And then I have 10 minutes, so it's demo time. And of course, it's the time where I want to show you that it works and there is a chance it doesn't, otherwise it wouldn't be fun. Chopping the monolith, which is not the right way. Chop monolith, new window. Okay, so here I have my architecture. Is it big enough for you? Good, so I work on the Apache API6 project, so I will be using Apache API6. Of course, you can use any API get where you want, but of course, I will be very grateful. My boss, if you used mine, but okay. API6 depends on ETCD, where it stores its configuration, its distributed key value store. Then I have my application, which I need to downgrade here. So I can show you the codes. And I have MariaDB, where I have all the data from my project. So who here is a GVM developer? Oh, not that many people. Okay, so this is a regular Spring Boot application with Kotlin. And the idea is I will start the stuff and then I can describe the codes. Docker compose up here. I have this pricing stuff. And at the moment, pricing is super hard. I just add the sum of all prices, right? The idea is not to show you how you can do a pricing engine, it's just to show you how you can change it easily. So I have this pricing stuff. And basically when I call it here, so I get the cards, I price the cards, and I return everything in one JSON payload, right? So when I go there, so here it should have started. I will just configure the API get away. So I send everything to the shop shop. And here is just to remove caches. So I don't have bad experiences during the demo. Okay, now I can, oh, I need to start Firefox. Yeah, I got interested in this stuff in the Czech language. I don't know if you see it. I don't know if you see it. Sorry, but I won't learn Czech anytime soon. And so I can go to local hosts. And I learned something that's not like only the Czech language, it's called syllabic consonants.  So here I add stuff to my cards. I will just check the network and I go here and here in one go, I got everything. So if I get here and I say the response, I see either total and I have the lines of my cards. And the origin is a monolith. I cannot make it bigger. You should have seated in the front row. But trust me, do you confirm this written monolith? Of course, thanks. You really want your stickers. I understand. Okay, so now to actually start my journey, I will need to make pricing not a regular function call but an API call. So now the pricing here and I will just update so it's Docker compose start chop, chop, chop. And normally at some point, no, I always forget it's up. It's not start is up. Yes. So at some point, yes. Okay, it's doing this. So the pricing now has become a route. So now I compute the route. So the client, the browser will first request the content of the cards. It will get the content of the card and we make another request to the pricing.  It's not the client that should do it. It's the API get away. But you understand I'm too lazy to implement further. So now I have this, I get back here. I go, I didn't implement the sessions. So I need to redo everything but that's fine.  So you can see it's another version. And now when I go to pricing, so first I have two requests and here the origin is still the monolithic. So now my architecture is ready to be chopped. What I did finally is I kept the whole stuff but I implemented the pricing in like JavaScript. Yes. And I put the codes on the Azure Fast. And so now the only thing that I need to do I don't redeploy anything. I just go here and I still have everything that goes to the monolith but I have one special endpoint, the pricing endpoint. And I say, hey, when I receive a post request on the pricing endpoint, well you just go to Azure instead. So I do it and now if I do like the refresh, like it should be like slower and then you can see Azure here. And I didn't redeploy the monolith. And now I can change the code every time I want on serverless and again it can be serverless, a rose engine, whatever I don't care. But basically I kept my monolith. So thanks for your attention. You can follow me on Twitter even though Twitter is now dead. You can follow me on master.down where I'm trying to find new and interesting content. If you're interested about the code itself because even you should trust this guy that it was everything was fine but probably I bribed him or whatever so you can get the code on GitHub and do it by yourself. And if I got you interested in Apache API 6 somehow just have a look, it pays my bills to come here so I can do better talks next year and I come back again. And now we have like three minutes for questions. Wow. Yes, thank you. You really want your stickers. I know. Remind me. So the question is, when do you stop chopping the parts of your monolith? When do you know what's the right time? So I will completely change the question because that's my privilege as the speaker. And I tell you the question you should have asked instead. The question is, when do you start chopping? And there is one single reason in my opinion to start going to microservices and it's not about any technical reason. The only reason you should start doing microservices is because you have too many developers working on the same code base. And my experience, and this is very personal, we started to feel the pressure at 70 developers. So we had a dedicated release manager who handled all the branches of the Git flow. It started to get really messy. That's at this level, we should have started to think, okay, what part can we start to chop? Before that time, scaling, hey, like stock overflow, they don't do microservices, they scale super well. So every technical reason you have to do microservices is probably bullshit, in my opinion. I accept stickers also. The companies that go on the stage and advocate for microservices, they have the right organization, they have many developers, and yes, they are at the point where the benefits of microservices outweighs the problems that you will get, like distributed tracing. But I believe that most regular companies are not mature enough to do microservices anyway. So unless you start feeling the weight of those like many, many developers, don't do it and we can talk afterwards because I'm out of time. Thanks a lot, I have stickers for everybody, don't worry. Thank you. And I have a talk tomorrow about open telemetry, it will be less funny but still interesting, I believe.


Dear students, in this module, we shall discuss the action potentials. Action potentials are the type of signals that neurons use to send information along the nervous system for long distances. The action potentials are brief but large changes in membrane potential that are propagated along the egg zone without decrement, that is, comehueh baghair poori intensity ke saath equally move karthi. The action potentials are very important as they control the effector responses, they control the activation of voltage-gated ion channels, they control muscle contractions, and they also cause exocytosis. In fact, action potentials are responsible for every sensation, every memory, every thought, indeed, every impulse. Abhum, action potential ki phases jeen phases me ye action potential mukammal hota hai, ye takriban five steps me mukammal hota hai. The first step is the stimulation. Second step is the rising phase in which depolarization occurs. The third phase is the peak phase and then fourth is the falling phase in which repolarization occurs. While the last phase of action potential is the undershoot also known as after hyperpolarization, hum in phases ko baribari detail ke saath study karenge. Sbse pehle hum stimulation ki baat karthe. When a stimulus is received at egg zone hillock, it, egg zone hillock woh jaga hai jahaan se action potential generate hota hai and this place has voltage-gated ion channels in it. So, the stimulus causes the sodium channels to open in the neuronal membrane. When sodium channels open, sodium ions start to influx. This results in change in membrane potential locally which is called depolarization. As a result of depolarization, membrane potential becomes positive, relatively positive. Then a depolarization of about minus 55 to minus 30 millivolt is known as threshold. That can trigger an action potential. If the intensity of the stimulus is less than this threshold, it is called a sub-threshold. It also causes depolarization but these depolarizations cannot initiate an action potential. After a threshold has acted on the egg zone hillock, sodium ions start to enter and membrane potential becomes less negative. This causes more sodium channel to open causing an even greater influx of sodium ions. Yaha pa positive feedback hota hai. Jiski wajah se sodium ions juju enter hota hai, utre hi zyada sodium channels open hota hai. Chunke ish wak tak abhi potassium channels bandh hota hai ish liye sodium current dominate kati hai aur membrane potential positive hona shuru ho jata hai. The sodium channels become maximally open. At this stage the positive feedback slows down. The membrane potential reaches a maximum that is close to the sodium equilibrium potential of positive 55 millivolts. At this stage further depolarization stops and it is known as the peak. Yeh ek thoda sa time jis daraan meh membrane potential positive range meh rata hai, ishe hain overshoot kati hai. Iske baat peak phase ke baat falling phase shuru hoti hai. Membrane dubara se repolarize hona shuru ho jati hai. The voltage-gated sodium channels start to close. So no further influx of sodium ions occurs. Voltage-gated potassium channels start to open. As a result potassium ions start to outflow. Ja potassium ions ka outflow shuru ho jata hai to membrane dubara se polarize hona shuru ho jati hai. And this continues towards the potassium equilibrium potential of minus 58 millivolts. Result is repolarization that is reversal of membrane potential. However the membrane repolarization initiates closing of potassium channels. Ja potassium channels kloz hona shuru hoti hai to repolarization ka process slowdown hota hai likin. Potassium channels delayed rectifiers hain yeh dir se activate hoti hai. Isli yeh potassium ions ka outflow jari rata hai. As a result the membrane potential dips even below the normal resting membrane potential. This means that membrane has become hyperpolarized. This brief hyperpolarization is known as undershoot or after hyperpolarization. It persists till the potassium permeability returns to the normal value.