One of the things that Linux users often do is they borrow other people's config files, especially as you grow as a Linux user, as you become more of a intermediate Linux user. You'll go and grab somebody else's dot files. They're config files. They're config files for their window managers or for Vim or for Emacs or whatever it happens to be. Most programs have configuration files that can be saved, and many Linux users do save these config files, which we typically will just call dot files. They're called dot files because most of these config files are hidden files, meaning they start with a period or a dot at the beginning of their names. Now one of the problems with you just going and borrowing somebody else's config file, there's several pitfalls involved, but most of the time when you go and grab somebody else's config file and just put it on your machine, it doesn't work. There will be errors. There will be some hoops you have to jump through sometimes. And today I wanted to discuss some of those pitfalls involved when going and grabbing someone else's dot files. And the reason I'm making today's video is because in here in the last week, especially, I have gotten many comments on my GitLab and also on YouTube of people trying out various config files of mine, and they're running into issues. I don't know. I'm going to mention at least one config file today specifically that I know are causing people issues. And I have some ideas on why it's causing certain people issues. And you know, instead of trying to answer everybody individually, I just wanted to put it on video. I also just thought it made a good topic. But one comment I got on a YouTube video the other day, I think sums up this problem rather well. He writes in, I love these videos, but every time I go to hack on them, I feel like there's a lack of information to get started. So he's talking about, you know, when you're hacking on a window manager, I think is as the video he was watching. I think it might have been one of my X-mode ad videos and there's a lack of information to get started. Well, I disagree. The information out there is just not user-friendly or new user-friendly because, you know, some of these topics get kind of deep. That's why you go and borrow other people's configs, right? Is because, you know, you don't want to have to dig through all the documentation. You hope that you just borrow somebody else's config and it magically works. But most of the time it doesn't. He goes on to write, I like how organized your configs are. I try to organize my stuff and comment heavily. So I appreciate that you find that useful.  There's no error messages, but then I get an error message and then I have to spend hours trying to fix the problem, yada, yada, yada. And yeah. So this is one of the first pitfalls that you run into when going and getting somebody else's config is the fact that you didn't write the config yourself, right? You're just taking the code that I wrote. So you don't really know what's going on in the code. And that's always going to be an issue anytime you borrow somebody else's code unless you happen to understand the language that it's written in yourself. But if you understood the language it was written in, you probably would have just written your own script to begin with. So most of the time when you go and borrow somebody else's dot files, you probably have no idea what the code is doing. And this is one of the things as you grow, as you start editing that config file and working on it yourself, you will figure out exactly what the script does eventually. But getting started, yeah, you're kind of lost at first. Now I mentioned that I've had several comments here in the last week about a specific dot file of mine. Let me switch over to my desktop. So if I go to my GitLab over at gitlab.com slash dwt1, I've got several repositories here. If I go to view all repositories, I have my dot files repository, which is a very popular repository. A lot of people use my dot files. And one of the most common dot files people grab are my xmonad configs and my xmobar configs. And this xmobar config here, xmobar rc, I have had a lot of people say they go and grab this file and they install it or just place it on their system in dot config slash xmobar on whatever distro they happen to be using. And this doesn't work. And there are several reasons why this is probably not working for you. And when I say there's several reasons, this is probably not working for you. This could be any config file, any dot file that you're going and borrowing from anyone. I'm just using this specific file as an example. But the first thing you have to consider when going and grabbing anyone else's configs is it's the config file up to date, right? How old is this? Was this placed on their GitHub or GitLab, you know, a year ago, two years ago, five years ago, 10 years ago, right? The older the config file, I mean, the older, since the last time it's been updated, the chances are that the program has been updated. That config file, the syntax has changed and, you know, you can't use it with newer versions of that particular piece of software. Now, in this particular case, I keep my configs relatively up to date. This xmobar rc should work as far as the syntax or there should be no syntax that is broken. It is something you do need to consider if I do a back arrow here. You will actually see, like on GitHub and GitLab, they'll actually tell you the last time these files were modified and pushed. So this xmobar rc was last updated two months ago, so not very old. But if you start seeing things that are many months old and certainly several years old, chances are, you know, you're going to have to figure out some of the new syntax if it has changed for that particular program. The next reason this config file may not work for you, even though it's working for the author, and you've got to consider these dot files, the people that are saving them to GitHub and GitLab, these are their config files, right? It's working for them. It's working on their machines. I use all of my configs, right? So I know these configs work on my machine, and that's part of the problem is the next big thing you have to consider is, are you using the same Linux distribution that the author of that config file is using? If you're not, that could be a major issue, because the version of xmobar I'm using on an ArchBase system, because I'm on an ArchBase system, right? It's going to be a different version of xmobar than what you're using on a Debian-based system, for example. You could be several versions behind on Debian than what Arch is on, and that could be a serious issue. And I actually think, in my specific case for my xmobar config here, that is actually the issue most people are having, is they are not using the same versions of software that I'm using. They're not on the same Linux distribution I'm using, an ArchBase Linux distribution. And specifically, what's causing people problems is that they mentioned that the xmobar panel, you can see this is xmobar at the top of my desktop here, these glyphs, these little Unicode characters are not rendering, so the fonts are not rendering. In my xmobar RC, this is the font section. And specifically, the glyphs are font awesome six, right? Here's the thing, font awesome six hasn't been around that long. On Arch, you can install it, I even made a note. By the way, read the comments of config files, because if the author of that config file did a good job, they actually gave you all the relevant information. For example, I included this dependencies line, I tell you, otf-font-awesome, that's the name of the package on Arch, unfortunately, right? So I don't know what it is on Debian or Fedor or anything like that. And also, I don't know if their packaged version of the font awesome package is on version six. It may be a older version. It may be font awesome five, which means you would have to change this on your system, right? This work, this config file works on my machine. I don't know if it's going to work on your machine. So some of this, you'll open issues on these people's GitLab or GitHub, and hey, man, your config file doesn't work. No, I promise you, please don't go and tell these people their config files don't work, especially if it's up to date, because they're probably using their config files, and it probably is working. It's just not working for you.  Don't ask somebody who authored that config file to help you out, because honestly, they can't. They're not using your machine. They're not using your Linux distribution. They're not installing the same packages and things like that. They can't help you. They've already done a tremendous amount of work by giving you this config file, right? All right, I put so much time and effort into these things, these config files, right? I've done a lot of heavy lifting here. The fact that, you know, you're having a problem with this font section, right? I'm gonna have to let you guys work out that single paragraph on your own. I can't help you myself. Another major mistake people make when going and grabbing somebody else's config file, I'm gonna go into .xmonad. We're gonna grab my xmonad config here, at xmonad.hs. Be very careful when going and grabbing a specific config file, right? Because a lot of people, well, I'll just copy and paste, right? I'm just gonna select it with my browser and this is a very, very, very long config file. I'm not actually gonna copy and paste it. But anyway, you select the whole file, right?  And here's the problem with a copy and paste from the web browser to your text editor. Certain programming languages and Haskell is certainly one of these. Python is another one that, you know, spacing is important in certain programming languages, right? This has to be indented, right here. You know, this block, this do block.  They have to be, right? If you do a copy and paste, sometimes it doesn't respect the spacing and the tabbing that was in the original document. And it will completely and totally break the config, right? Even though the config probably does work on your system, you know, if you did that copy and paste and it's a bad copy and paste where it messes up all the indentation, it's going to break on your system.  It wasn't broken if you would have done the copy and paste the right way. And the right way is to not do a copy and paste. What you wanna do to make sure you get the original file as intended is to actually clone the repository and so go to the very top level of the repository and you have clone here and then you have clone with HTTPS. Grab that link. So just do a copy of that link right there and then open a terminal. Let me open it and we'll make this big and I'll CD into downloads. And then what you wanna do to clone a get repository is get clone and then the URL to that repository, right?  Now say you go and grab somebody's config file and you put it on your system and it does work which much of the time that will be the case. You'll grab somebody else's working config file that, you know, it works on their system and it'll probably work on your system too. And then you decide, well, I wanna tweak some things. I wanna change some things. And as you're changing things, you break the config. How do you avoid that kind of pitfall? Well, let me switch over to my desktop and I'm gonna just as an example, let's open my Xmonad config. Let me zoom in a little bit here.  For example, you know, my terminal is a Lackardy. Maybe you wanna use a different terminal. Maybe you wanna use URXBT, right?  That's probably okay. That's a really simple change, right? But the problem is when people start making massive changes to things or, you know, maybe you wanna change a lot. I wanna change the font. I wanna change the mod key. I wanna change these variables for terminal browser, I don't use Emacs, I use Vim. So I'm gonna change that string as well. And then I'm gonna change everything in the startup hook, all of this stuff. And then I've got some workspace information down here somewhere toward the end. Maybe I wanna change all the names of the workspaces. And then I've got rules for various windows, whether they're floating or tiling, yada, yada, yada. And I'm just gonna make all of these changes, keybinding changes. I'm gonna make a million changes to this config file. And then I go and recompile Xmonad and it doesn't recompile correctly. I get a bajillion errors. And you made this massive change to this massive document, right? What's the error? What mistake did you make? You have no idea because you changed so much stuff before trying to recompile. You have no idea what caused the error. So when you're changing these things, change one thing, make small changes, then recompile, then restart, in this case, the window manager or whatever program you happen to be working in, make small changes and then see if it works. If it works, then make the next small change. Don't make a massive change because if things don't work, it's very, very, very difficult at that point to figure out where the error is. And many times you're wasting time doing that because now you spent 30 minutes making this massive change that didn't work and eventually what you're gonna have to do is go back and do exactly what I told you, which is to undo everything you did and then go add things, one chunk at a time, one small little chunk at a time and then you will eventually figure out, okay, this is where I made the mistake. One thing you have to be careful of at any time you're editing these config files or just programming and scripting in general. I mentioned doing the small chunks and then sometimes you'll make a mistake. You need to be able to undo what you just did so it would be nice if the text editor or the IDE that you're working in has the ability to undo a lot of changes or maybe even go back to the last saved state of the file. So you may wanna think about the text editor you're working in, for example, here in Emacs because I'm using the Emacs server, the Emacs daemon, which typically I never kill it. I can probably undo a lot of stuff I've done on this config file for the last several days depending on when the last time I restarted my computer was because restarting the computer, of course, will kill the Emacs daemon. But I can undo a lot of stuff on these various files I work on just because Emacs is always running on my system, right, and it remembers the history. Even if it didn't, Emacs has saved states of files that I can roll back to and that's really important. So that's another thing if you, once you start getting heavy into playing with config files, dot files, especially once you get into scripting, you may wanna consider the text editor that you're using. So these are just a few of the errors that you can encounter when going and grabbing other people's config files, other people's dot files. I just wanted to make you guys aware that maybe you didn't know, because I see too many people going on GitHub, GitLab and telling people, hey man, your config files don't work, your dot files don't work. And be careful how you approach that. It would be better if you asked that person, hey man, does this config file work? I tried it and didn't work for me. Is it working for you? Ask them that first, because 99% of the time their config file is working for them. That's why they're saving it, it's because it works. And then you'll realize it's probably one of these other issues that's the problem for you. Now before I go, I wanna thank a few special people. I wanna thank the producers of the show, Devon Gabe James Maxim, Matt Michael Mitchell, Paul Scott West, Alan Armoredragon, Chuck Mandarin, Greta Iokai, Dylan George, Lee, Lennox Ninja Mike, Erion, Alexander Peace, Archon of the Door, Polytech Realiteats for Luts, Red Prophet, Stephen and Willie, these guys, they're my highest tiered patrons over on Patreon. Without these guys, this episode would not have been possible. The show's also brought to you by each and every one of these ladies and gentlemen. All these names you're seeing on the screen right now. These are all my supporters over on Patreon because I don't have any corporate sponsors. I'm sponsored by you guys, the community. If you like my work and wanna help me out, look for DistroTube over on Patreon. All right guys, peace. And add comments to your dot files if you plan to share them.


I was a bonehead. You can't just throw Twisted. Twisted and Do-It-Dot can't sit in the room with bones.  You're crazy. From the first to second album?  They can get in that room. It's the first of them all. Wake up. Before it was a Pem-C, it was a bone thug of hominy in my life. No, Pem-C was before that. No, not for you. Before that Pem-C was not before Crossroads. Larry Hoover Jr. did his birthday party and I heard Crucial Conflict. I interviewed Do-It-Dot, Twisted. Man, that's what I'm trying to do.   Definitely AK. You did? Man, listen.  It seemed like they together. I told them that on the interview. Y'all seemed like a group. If you gonna sit up there and do Pope Pem-Pen and I, At the party? All them niggas couldn't do. Do you? You gotta leave it on to Twisted. To Twisted what? It's like Twisted was more floorly with the people. Nah, them niggas was all hidden, man. Twisted, of course, is different kind of animal, but them niggas was hidden, bro. Man, who you say Midwest? You got Shona in the Midwest, too? Nah, Shona.  See, he don't ever do this. Listen, listen, listen. I got. R. Kelly in the Midwest. Nah, I got you. This is what I got. I got R. Kelly first. I won't go say that until you say that. That nigga bad. R. Kelly is first. I got Bone Thugs. Bone Thugs and homie. They from Connecticut, ain't it? No, they from each nine and nine. That nigga Cleveland, nigga. Cleveland and none is what you find, man, baby. And then I got Twisted. Twisted. Who's the hardest out of Twisted and Bone? Bone.   I am. Man, you never know who can win that. That'll be a toss up. What?  Man, I was a Bone Thugs. I was a Bone Head. You can't just throw Twisted. Twisted and do it. I can't sit in the room with Bone. You're crazy. I'm the first and second album.  It's the first of them all. Before it was a Pimp C, it was a Bone Thugs and homie in my life. No, Pimp C was before that. No, not for you. Pimp C was not before that. Pimp C was not before Crossroads. Look it up, look it up. Nigga Pimp C was in 93, 92. Do you want to listen to Pimp C 92? Yes, I was. I'm a real Pimp C fan. Man, I was listening to them Niggas in 92 or 93. They did Pocket Full of Stones way back then when they first came out. And they had one before that. 1989. Bone Thugs and Crossroads. Bone them came out. They were on the same time, might be a little later. When did Easy bring them boys out? No. No, it was by 97. Yeah, because I was old. 96, 97, so no. Chill is the last nigga, but this time you better move a gat. Nigga, that's B-U-N-B. Man, that first album, man. And then Super Tight. By the time they came out what you talking about, man? Ryan Dirty was out. Ryan Dirty was out when that came out. They already had two in the basket. 96. See what I'm saying? I'm talking 93. Go look at Pocket Full of Stones. Go look at the first album which it was on the dude that passed away being bummed was talking about. Big Time. It was on Big Time, the first one. And that was before they even signed the job. Let me ask you a question. That's why I got you by age, I know. And Bull is going to be mad at me. Definitely going to be mad at you, because he watch Boss Talk. You better on here. Nah, no, I love it. I still eat at Trip Burgers. Look. Listen, just to hear some pimps, he listen. Alright. And I want to ask them though too. 92. I'm old. I've been listening to it. But they went boomin' until 96. No, you're crazy, man. Why you think I cut for him? Boss Talk was bigger than them in 96. No, no, no, no. Not for me? Damn, not Ryan Dirty. Jase even knew that whole while he come down here. Let me ask you a question. Why Bond couldn't keep it up after Pym died? Man, it's tough. That's the tough pill to swallow. Pym was locked up, then he come home, and then he died. Man, that's a lot to come behind. But look at when you lost mode three. You was depressed. You was in a depression for a while. Yeah, but if I was a rapper, I'd be... No, you can't say that. You can't say that. It's hard to come behind. Pym C locked up, then Pym C died. How long did it take him before he died? It wasn't long. It wasn't long at all, actually. They say his body was so slow. Yeah, he had been out of the... I think he had been in that room for a while. How long? I don't know. They just told me, they was pretty much just telling me the details of how the body was when it came. What did they say? I can't really... He didn't get into much detail. You know what he said that was crazy? Because he said he didn't want to come on Boston, he just wanted me to know because I always talk about Pym C. And he was pretty much just telling me that Pym C ended up at a white funeral home instead of a black funeral home. So that was odd because white people...  So that was odd for him.  That's why I left. That's all he said? That's all he kind of stopped with me. No, Mo3 went to a white funeral home. He did, too?  They might take a picture of your body. Oh, that makes sense. I didn't think of it that way. So you're saying the white funeral home is more professional?  You'd rather go to a white man? You have some very reputable black funeral homes. Don't do that. Listen, we shoot a lot of videos in black funeral homes. Every video that we shoot...  No, he'll not take me to the white man.   I probably don't talk down to one of his cousins.  Kissing on me every day. You dead anyway? No, give it to them. So at the end of the day, send me to the white man.


Thank you very much and good day to everybody. Sorry for having been a little late, but we just passed some very important reforms for the organization. But let me start by saying how very pleased I am that we are holding this in-person, general assembly the first time we have brought our membership together since we met 2019 in Santiago de Chile in the Americas. And I'm very grateful to the Turkish authorities for their wonderful hospitality here in Istanbul and for their efforts to make this event also a COVID-19 safe event. We all know that this meeting takes place under the conditions of a pandemic or a challenge in itself. I would also like to welcome the federated states of Micronesia as our newest member country bringing the numbers of member country now to 195. Since the last Interpol General Assembly in 2019 the world has been completely disrupted as we all know by COVID-19. At the same time we have seen a kind of parallel crime pandemic all around the world. Police saw criminals exploiting opportunities to turn the health crisis into an opportunity to make illegal profits. Fake COVID-19 vaccines shipped from one continent to another, a steep increase in online child sexual abuse and especially a surge in cybercrime ransomware, one of the particular examples in some regions the increases amounted to several hundred percent during the crisis. The billions in illicit profits that organized crime networks are making especially in drug trafficking is increasingly infiltrating our societies. I listen carefully of course what chiefs of police from member countries are telling me and they are increasingly concerned that again organized crime with the millions and billions they are making these powerful criminal global enterprises are undermining our societies investing into the legitimate economy and therefore causing a major threat to our societies in almost all our member countries. The only way for law enforcement in our member countries and I mean all of our member countries to combat transnational crime is through international police cooperation. There's already a lot going on but the globalization of crime of terrorism is continuing and the challenge for national police services definitely is to invest more in international police cooperation that costs resources. They need the specialized stuff to cooperate on an international level but this is exactly why Interpol was created for one for almost 100 years to provide that safe and secure platform for police cooperation. Since 2015 Interpol has seen the number of records held in our 19 global databases grew by 69 percent and now contains some 116 million police records. Already this year alone 2021 our databases have been searched nearly three and a half billion times but what we are seeing is still just the tip of the iceberg. Crimes such as fraud or cybercrime are massively unreported for various reasons very often victims of these types of crime are not reporting their illegal activity to law enforcement agencies and the judiciary and many countries that are also represented here in Istanbul simply do not have the technology or the training capabilities to tackle these modern and let's say more old-fashioned crimes that are now appearing also in light of using new technologies in the appropriate way. Interpol is of course uniquely positioned to help our member countries address these issues even where sometimes diplomatic relations between member countries are crucial, difficult or even not existing at all. Interpol's neutrality and independence is essential as Secretary General I'm committed to ensuring we remain an essential and trusted partner indeed the backbone of a global security architecture to tackle these types of crime. This is why this gen assembly will discuss a gradual substantial increase also in our statutory contribution so these amounts of money that we are receiving every single year from our membership to build our secretariat work in a sustainable way. It is also why member countries will be called to approve a set of reforms to our governance that is what we have been discussing this morning and these reforms concern first and foremost the executive committee that is the body that supervises my work and the work of the roughly 1,000 men and women in the general secretariat and the adoption of a code was agreed just before this meeting here took place now introducing a clear set of rules regarding the ethics accountability integrity by its members which means the members of this executive committee. We are and that is important to state also on this occasion here we are a technical police organization we are not a political organization but this does not mean of course that we are blind to today's geopolitical realities which are not always making our work easier. Recently we have seen various commentaries on Interpol most of which unfortunately has been either uninformed or misguided. Let me start with a few words on one of the most well-known but also very effective tools this organization operates the so-called red notices. To first clarify that a red notice is not an arrest warrant. In 2016 I created a specialized task force which reviews every single red notice request from every member country to ensure that it is compliant with our Interpol constitution and the rules of procedure. Why is that important? Because we have a limited mandate. We are not allowed to enter into any issues that have been predominantly a political, a military, a racial or a religious character. Interpol has simply to stay away from these activities. Second the difference between the secretary general and the president. You know that on day three of this conference we have elections for the supervisory body the executive committee which is presided by the president of Interpol. The president of Interpol also presides this general assembly here in Istanbul or any other general assembly. The president of Interpol remains a full-time official of his or hers country where he or she is coming from. The main role is again in executing this supervisory function on behalf of the membership that means normally meeting with the fellow members of the executive committee three times a year doing the sessions of the executive committee and in all the time in between if I may say the person remains a full-time official of the country where he or she comes from. Others is the secretary general. I'm not a member of any government. I'm neutral. I'm independent. And my role is to conduct the day-to-day operations of the Interpol general secretary. So the day-to-day operations of Interpol. So what I sometimes heard in the news that a member of the executive committee is taking over country is taking over Interpol. That doesn't mean at all the reality of the clear governance structure which we have in our organization. We have again today been strengthening that mechanism the system of checks and balances within our organization. But again the person that is running the day-to-day business of Interpol that is the secretary general just to clarify that on the occasion of the elections that are coming up on Thursday. So that concludes my remarks. Maybe just to finalize with the information that in two years from now Interpol is celebrating its centenary. 100 years we were founded in 1923 in Austria in Vienna and during this General Assembly there will also be a vote on the venue where the organization is meeting in 2023. Next year we will be in India 2023. We will hopefully be in Austria. We have a request from the government of Austria to be decided here in Istanbul. And the schedule is already ready for 2024 where we are going to meet in London in the United Kingdom. Just to provide you this overview in terms of the calendar that this General Assembly, our supreme decision-making body is following. So thank you very much. This concludes my introductory remarks.


भ्व वाद्द,लगाद, किल एक लिए यो तर और रव, देखेगाद तूवाद यो वाद्द साथा, बीम में स़ाच्टा आप सदाच करनेवाच। आप स्झाद फूँ फूँ आप या कचीग वॎद्द बागर, बं वो साद्द करनेवाच थीजंवाच करनेवाच बना सीगावार अप्षेंटी के सीखावार वेड़ा सेखमने की साथ वेड़ा सीखावार ठीचो आउत द knees अफना कि क्यों मुझा सक्चिस क्यों छोगे दोगों ऽद पर दो वोड़ग करिरदा सेखमने कि सच्चिस के थी सच्छिस अद होगें which has infinite wavelengths there is no as in fixed wavelength that only this wavelength will come out it's a continuous so it has infinite wavelengths all wavelengths are possible so incandescent electric lamp has that property it produces a spectrum of continuous emission nature what about third third question in fact we have done in the class itself can you try this out no one third question should I wait or solve wait or should I solve ok so on the day I saying third that's correct fine let me solve this question now you have n number of turns that is wound tightly in a form of spiral with inner radius and outer radii a and b respectively when a current of strength i is passed through the coil magnetic field at the center is asked so let's say this is the bigger circle and that let us say is the smaller one ok inner radius is a and outer radius is b alright so within a width of b-a total number of turns are capital N fine now the problem is that I know the magnetic field due to a ring right magnetic field due to a ring is mu naught i divided by 2 r ok but then but then these are like multiple rings are there ok and different radii so you can't use the direct formula so you have to take the help of integration alright so at a distance of small r at a distance of small r you assume a ring of width dr ok pardon my drawing so at a distance of r I am assuming a ring of width dr so if it is at a distance of r magnetic field will be this if it is only one turn ok but if there are some number of turns which is let's say you know N1 then magnetic field with this now in this width of dr how many number of turns are there number of turns per unit width is N divided by b-a this into width of the ring dr this is N1 ok or you can write this as differential element you can say that this into dN this is dN ok number of turns so it will be mu naught i divided by 2 into N divided by b-a ok multiplied by dr by r this is the magnetic field because of the ring this one total magnetic field will be integral of that and the value of r goes from a to b when you integrate dr by r you get ln r ln b- ln a which is ln b- b by a that's option number 3 now these kind of questions people already solve and then go and take the exam so they already know most of the time the direct answer this is a very common question alright we will go to the next these three questions solve one by one and answer you can answer one by one ok fifth one the answer is 3 fourth one the answer is 2 see this is how you have to solve this question you have a ray of light that is incident at an angle of 60 degrees so this is the incident angle 60 degrees what will happen to this it will reflect off follow law of reflection and this angle will be 60 degrees what is asked is angle of deviation so angle of deviation is this much so 60 plus 60 plus this angle should be equal to 180 degree because this angle this line is straight line so that's why it is also 60 degrees fifth electric potential is given as this you need to find electric field now we know that electric field along x direction is minus of dv by this is partial derivative of v-2x so this is minus of 6x and when you put x equal to 2 you will get minus 6 sorry you get minus 12 option 3 is correct for fifth now solve question number 6 feel free to refer to your notes this is not the test you are writing feel free to refer to any formula, equation whatever notes you have you can do that samdara has answered sixth note samdara that's not correct remember this fringe width is how much lambda d by small d directly fringe width is given 0.3 mm so it remains 0.3 mm but fringes will shift fringe width will not change fringes will just shift understood everyone any doubts till now quickly type in let's move to the next one these three you can solve one by one first solve question number 7 let's discuss it and then we will solve going forward next question seventh near a server loop of conducting wire as shown electron moves along a straight line the direction of induced current will be lost now electron is moving in this direction so current is in opposite direction and if current is like this if current is like this the magnetic field will come out of the loop understood fine so what will happen is that as this electron moves away and away from here the change in flux also changes getting it if it is nearby the rate of change of flux when it is just passing this center when it is coming towards the loop the rate of change of flux is positive when it is going away from the loop rate of change of magnetic flux is negative so rate of change itself is changing so that's why it is variable when flux is changing then only induced current will be there so depending on what is the rate of change of flux induced current will show its behavior eighth one this one there is already answered others quickly answer hydrogen atom from excited state comes to the ground state by emitting a photon of wavelength lambda if r is a rickbook constant then you know that 1 by lambda is rickbook constant 1 by n1 square minus 1 by n2 square this you know so if wavelength is lambda so 1 by lambda is equal to rickbook constant r it comes to the ground state so 1 by 1 square that is 1 by 1 minus 1 by n square so from here you will get small n to be equal to this what about ninth during the formula of magnetic dipole moment how much it is magnetic dipole moment formula is what n i a it is n i a so it doesn't depend on the magnetic field in which it is lying it only depends on current area and number of turns so option 4 let's go to the next it's a theoretical question option 4 is correct if it is unstable if it is just unstable it doesn't need outside potential difference to create the laser but you need potential difference or current through it right sorry just one second it is metastable to ground state actually it I mean lower state is also ground state only but then ground when I say ground state after that it doesn't emit anything okay so metastable to the ground state where is 10th one from see 10th one is from communication system or you can say EM wave EM wave will be better it's from EM wave which is based on actually your general knowledge only okay right time to test your general knowledge whether you are going beyond the syllabus little bit anyways 11th okay others what is the answer for 11th of an infinitely long straight wire then a magnetic field is a thin walled pipe so basically it's a hollow cylindrical pipe current is flowing on the lateral surface okay current is flowing on the surface of it it will be zero inside the pipe okay you can imagine an ampere circuit a loop like this inside okay so you can write down b into b dot dl integral is equal to mu naught i that is passing through the loop current passing through the loop is zero so this is zero and because of the cylindrical symmetry b dot dl should be equal to b into 2 pi r where r is the distance at which you are finding the magnetic field so b has to be equal to zero fine so magnetic field is zero anywhere inside the thin walled pipe this is from your NCIT we have done this question in class also let's go to the next question it has four question one by one please solve anyone got okay 12th yes 12th is third correct so this is right so 1 by f will be equal to mu 2 by mu 1 minus 1 1 by r1 minus 1 by r2 okay so length is made of focal length in air so mu 2 is 0.15 so when you substitute in the formula 0.15 divided by it is oh sorry focal length is 1.5 so focal length is 1.5 in air 1 divided by 0.15 is equal to refractive index of the glass of the lens is 3 by 2 so in air mu 1 is 1 this minus 1 1 by r1 minus 1 by r2 okay and then we need to find out this focal length inside the water so 1 by f is equal to 3 by 2 divided by 4 by 3 now minus 1 1 by r1 minus 1 by r2 okay so these are the two equations 1 and 2 so if you divide it you will get f divided by 0.15 is equal to you know when you divide these two will get cancelled away so you can simplify and get the answer okay so 12th answer 3 is correct 2 sources are said to be coherent if they have the constant phase difference we have discussed this also explicitly in the class okay then 14th 14th you are saying 1 yes that is correct we have 3 registers 1 2 and 3 that are connected to form a triangle so is like this 1 ohm 2 ohm and 3 ohm the current sorry across 3 ohm the 3 volt battery is there so 3 volt battery is there like this we need to find the current through 3 ohm now if you find equivalent resistance the current through the equivalent resistance is same as current through 3 ohm because equivalent resistance will also be between these two points only so equivalent resistance will be 2 and 1 they are in series and that will be 3 so 3 and 3 are in parallel so 3 by 2 will become equivalent resistance okay so current will be 3 divided by 3 by 2 that is equal to 2 ampere option 2 is correct for 14 we are saying for 14 1 how okay I am sorry okay I was rushing actually sorry about that see the current through the equivalent is not equal to current through 3 ohm there are two different things current through equivalent will be sum of these two current i1 plus i2 current through equivalent will be this current alright so potential difference across 3 ohm is 3 volts so current will be 3 divided by 3 which is 1 ampere you are correct option 1 is correct for the 14 okay 15 in common emitter amplifier the input signal is applied across what yes base and emitter right fine so like these you can solve these four questions should we move to the next question any doubts quickly ask if you have any doubts please 1 by 1 16 and then 17 16 16 16 is saying 2 others see we know that number of nitrya after time t is n equal to n naught is the power minus lambda t okay and for the mean life t is equal to 1 by lambda you know this right half love is 0.693 by lambda and mean life is 1 by lambda so number of nitrya remaining will be n naught e to the power minus 1 okay so option 2 is correct that will be n naught by e is equal to n after 1 mean life so n naught by this will be equal to e 17 17 anyone do remember the lateral shift formula okay lateral shift is t sin of i minus r divided by cos of r this is what we derived right shift i is the incident angle r is the refraction angle refracted angle yes 17th is first just have to substitute the values over here okay and lateral shift produced is 1 by 3 for 1 unit of thickness so t is equal to 1 this is sin of i cos r minus cos of i sin r divided by cos of r okay so i is 45 degrees you can get the value of r so 1 by root 3 will be equal to sin of i minus cos of i tan r so sin of i is 1 by root 2 and then cos of i is also 1 by root 2 so you can get the tan r so tan inverse of whatever you get option 1 fine i will go to the next question okay alright so these are the next few questions you can solve them one by one we can discuss it one at a time okay 19th 1 28th 2 yes 98 1 is the answer 20th 2 is the answer oh sorry what i am doing you guys are solving 90th and 20th not the 18th 90th is 1 correct and 20th is 2 correct so Newton's for corpuscular theory was not able to explain why the light decreases its speed when it moves to the denser medium so if you apply that you will get it wrong so that's why wave theory is used to prove the refraction law isn't it the wave optics starts with the proof of the Snell's law 18th when material use in transformer must have high permeability and low hysteresis loss high permeability will make sure the magnetic field is higher and low hysteresis loss will enable lesser energy loss lesser power loss okay so these are 18, 19, 20th what about 21st 21st also you have answered potentiometer see how simple these this is actually CET paper whatever we have done in previous few problem solving session like last two problem solving session I was doing comet K so CET equations are relatively easier than comet K this is CET 2009 okay let's go to the next one solve these 22nd 2 the changes by what factor you know that the wavelength is h by p it depends on the momentum and momentum can be written in terms of kinetic energy as under root of 2M into K if kinetic energy is tripled the new wavelength वी वन of aluminum is row 1. वी वन of V1 of G. जी is MG force downward and upward direction. वे�स होँ पारचेगागागागागागागागा, वेप बूध यी, वेस आप वुझ की साथा. समच अखाच, वेप टी, वी की वी या जी, what does it mean correct so rho 1 v 1 g minus rho w v 1 g this is the net weight inside the water this should be able to rho 2 v 2 g minus rho water v 2 g okay now tell me which is higher v 1 is higher than v 2 is this correct difference in balancing yes that is what so listen here rho 1 v 1 g will be equal to rho 2 v 2 g okay minus of rho water into g v 2 minus v 1 okay now this aluminum is density of aluminum is less than the density of steel okay that you should know as general knowledge so volume of v 2 will be less than v 1 actually okay so v 2 minus v 1 will be less than 0 okay wait yeah sorry v 1 will be greater than v 2 find this tells us that v 2 minus v 1 is less than 0 okay so from here you can understand that this is more than that okay because there this thing will be negative quantity negative into negative will be positive so the mass of the mg of aluminum is more than the mg of steel by a factor of this so aluminum piece will be more when you weigh in here understood all of you i will go to the next question now these questions annihilation means that you have converted the mass into energy kilowatt hour kilowatt hour the unit of energy is kilowatt hour kilowatt is the unit of power okay so for 25th one microgram of matter is 10 raise to power minus 3 sorry minus 6 actually okay minus 6 how much energy it will release mc square that is 3 into 10 raise to power 8 whole square fine this much energy will be released and you should know what is 1 kilowatt hour equals 2 if you know it in terms of joule you just divide this with that if you don't know it it is 10 square 3 into into number of seconds and r has 24 into 60 into 60 it's a good idea to remember how many joule one kilowatt hour has so this when you divide that you'll get the answer 25th answer 4 is correct i hope you are not using calculators 26th the thing has answered 1 26 the answer is 1 okay number of significant figures in these numbers we have to count so basically here you know after decimal 0 are counted okay so you can see that it has 1 2 3 4 and 4 is also counted so 5 so now between 1 and 4 we need to see which one you can see over here you have these 5 and these 2 7 so that's a option 1 for 26 27 beta decay means emission of electron from from a radioactive nucleus right with every radioactive decay happens from the nucleus only it's a phenomena of the nucleus okay electron do not take part 28th anyone answer 28th okay 28th yes 28th is first let's see how an electric heater rated 200 volts and 500 watt is connected to ac mains the current drawn by 8 is watt so you know you can simply multiply v and i and equate that to power we are assuming that this ac mains has the rated voltage only we have assumed that the 200 200 into i is equal to 550 this the values are not proper in the book they have assumed there's to be 220 volts fine so the there is some correction required in the question but anyway you i think you have understood how we can solve this question okay here is shriram okay let's go to the next question finally some mechanics questions so it is seen that in ct paper the mechanics questions are the later part of the paper the first part is mostly class 12 syllabus so usually this is what is seen it may or may not happen again but just that i'm telling you and usually all class 12 syllabus questions are together and all class 11 syllabus questions are together okay pratik has answered 30th before answering anything else that's a good strategy you should look at the you know you can understand 30th is you know smaller question so it's a good strategy to answer the easier ones first 30th the moment of inertia of circular ring of a radius r and mass m about the diameter is mr square by 2 that's correct okay you can use the perpendicular axis theorem about this axis the moment of inertia is mr square so that is equal to sum of moment of inertia about these two and due to symmetry both of them are equal so about this one axis it will be half of about this axis anyways other questions 29 and 31 others are not answering what happened are these difficult let's see 31st question a body of mass 0.05 kg is observed to fall with an acceleration of 9.5 meter per second square the opposing force of air on the body is what so we know that the force due to gravity will be mg okay and there will be an opposing force let's say that is fo okay so net force is what mg minus f0 this should be equal to mass time acceleration which is 9.5 okay so f0 will be equal to m times g which is 9.8 minus 9.5 fine mass is 0.05 into 0.3 so it will be 0.015 Newton 29th see you can see clearly by the time you guys were answering one question others who have tried solving these two have answered these two question before you could even solve 29th okay so the learning is you don't need to go sequentially okay save time as much as possible anyways let's try to solve 29th a body of mass m moving along a straight line covers half the distance with speed of 2 meter per second the remaining half the distance is covered in two equal time intervals with a speed of 3 and 5 average speed is what we need to find out let's say distance is d so this distance is d by 2 and that distance is d by 2 okay so this distance is covered with 2 meter per second all right now from here to here you have two different speeds 3 and 5 okay so it says that the total time can be divided into two equal parts let's say from here to here total time is capital T so this is t by 2 and that is also t by 2 okay in equal time intervals these two distances are covered with the speed of 3 and 5 okay we know that the average speed of the entire journey is total distance by total time taken let's say total time is t0 okay so can you get the you know here can you get the value of t in terms of d by 2 in terms of d and velocity try getting it okay so let's try to solve now see here the first part the velocity is 2 meter per second sorry 3 meter per second and the next part it is 5 meter per second okay let's say time interval is t by 2 so t by 2 into 3 plus t by 2 into 5 this should be equal to d by 2 right total distance so from here you can get the value of t is equal to d by 8 okay so average speed is total distance d divided by time so from here to here the time taken is d by 2 divided by 2 plus total time from here to here is t which is d by 8 okay so you can see that d get cancelled away fine and you will get it as 1 divided by 1 by 4 plus 1 by 8 that will be 32 by 12 4 3 is a 2 8 by 3 okay 8 by 3 option 1 is correct fine let's move on this is from chemistry colloidal solution we'll leave this 33 33 and 34 okay 33 is saying third 33 answer yes 33 answer is third scattering is happening our intensity reduces in the direction of the lens next one 34 anyone no one the answer is 2 it can balance only when it can balance only when all of them are acting along one straight line okay but three neat one acts like this two and one act like that then only it will be balanced okay otherwise you know some of two sides of the triangle will always be greater than the third side if you add them vectorally it will follow the triangle of addition right so they should add up to zero fine we'll go to the next one all these prathik is martyr and suddenly we founds one quick question to solve okay let's go one by one over here sound wave transfers what momentum or energy or both let's see what is sound wave sound wave is a longitudinal wave where suppose these are the particles okay let's say this particle starts oscillating then it will make this particle also start oscillating then this particle also starts oscillating so like this the all the particles slowly slowly oscillate as the wave travels in this direction okay and if this particle suddenly increases its amplitude then everywhere the amplitude will be increased correspondingly and if velocity increase everywhere the velocity will be increased correspondingly okay so the energy is the wave and the momentum is the particles velocity which is coming in as the wave move forward okay so both energy and the momentum gets transferred okay 37 is gp thompson experimentally confirm the existence of matter wave by phenomena of diffraction okay this you should know it as a fact okay now 36th read the question and solve anyone 36 should i solve what is the condition for maximum compression when the maximum compression will happen what do you think at a maximum compression what happens how to identify it see this is this has velocity this has no velocity okay so initially what will happen this block will come closer to b okay then slowly and slowly b will gain the velocity all right but then it will keep a will keep on coming closer to b till the velocity of b let's say vb becomes equal to velocity of a okay so condition for maximum compression extension is that their velocities are equal then only they will stop coming closer to each other or stop going away from each other okay now let's say this is equal to v all right so if we have assume these two as one system okay the momentum will be conserved or not tell me momentum will be conserved in horizontal direction or not it will be conserved even though spring is there because spring is because spring is applying a force which is internal to the system spring is a part of the system okay the mass of a which is two into its velocity this is the momentum initial momentum this will be equal to two plus three into the final velocity because final velocity is same for both of them from here you get velocity and then you apply conservation of energy or work energy theorem u2 plus k2 minus u1 plus k1 okay w is 0 u1 is 0 k1 is half mass of a is 2 into 0.15 square k2 now both the masses are moving in the same velocity so that is 2 plus 3 into v square and u2 is half kx square solving this equation you get the value of x which is the answer understood all of you any doubt let's go to the next question okay others we are going to use r equal to r not 1 plus alpha delta t okay r is 0.6 this is equal to 0.3 1 plus alpha is 1.5 into 10 is power minus 3 delta t okay so from here you will get the value of delta t all right delta t is equal to final temperature minus 300 kelvin fine so you will get the value of final temperature remember you will get the final temperature in kelvin because you have written 300 is as kelvin okay so option number 2 is correct when you solve 49 1 the work done by the force on a body as shown in the graph total work done in converting an initial in converting an initial distance of 20 meters covering the initial distance of 20 meters will be what the area under the graph okay so area till here this area is the work done because integral of f dr this is the work done and mathematically this is nothing but area under the force and displacement curve okay so you can connect this point like this and divide it into a trapezium and a triangle okay you get the value of area 39 answer 1 is correct 40th 40 resolution formula is required over here if you don't know please refer to the book similar question we have solved in last problem solving practice the formula is this theta is the angle of resolution minimum angle of resolution this is given as 1.22 lambda by d d is the you know diameter of the aperture which is your eye only in this case okay and theta is what theta is this angle suppose you are viewing two small objects from very far this is your eye okay the angle subtended by these two points this is theta okay and how you find this theta if this distance between the two point is d and this distance is let's say l theta is equal to d by l okay where d is a distance of separation so d divided by the length which is 10 kilometers that is 10 is power 4 meters this is equal to 1.22 lambda is 500 nanometer that is 5 into 10 is power 7 meters divided by aperture which is 2.5 into 10 is power minus 3 okay so you will get 2.44 meters fine let's go to the next question solve these okay 41 two different answers for 41 a door of 1.5 meter wide requires a force of one Newton to be applied at the free at the free end to open or close it the force that is required at a point 0.4 meter distance from the hinges for opening or closing the door is what now opening and closing of the door is nothing but rotation of the door right so torque should be equal in both the cases because angular extension should be same to open it so basically if it is 1.4 meter wide one Newton the torque applied is 1 into 1.6 this should be equal to torque applied by the force which is 0.4 meter away okay so the force will be 4 Newton option 3 43rd spectral lines of hydrogen atom that lies in visible region of electromagnetic spectrum is bomber series right bomber was a teacher in a school who has conducted several experiment because of lack of instrument he could do only for the visible spectrum so he came up with the first set of spectrum that is bomber series okay 42nd 0.1 meter cube all right anybody else solve 42nd yes on that that's correct 0.1 meter cube of water at 80 degree Celsius so 0.1 meter cube at 80 degree Celsius is mixed with 0.3 meter cube at 60 degree Celsius you need to find the final temperature okay so basically what will happen is that this 80 degree Celsius will lose the heat and 60 degree Celsius will gain the heat okay definitely it can it can't be 60 right because temperature will lie in between and the more volume is with 60 degree Celsius so answer will be closer to 60 it can't be 70 it would have been 70 if equal volume mixed then it will be the average of these two it can't be 75 because 75 is closer to 80 but with 80 the volume is to answer will be 4 only let's see how to do this so let's say mass of this is m so mass of that will become 3 times m right so 3 m into specific heat into t minus 60 this should be equal to m into specific heat into 80 minus t m into s so you'll get 3t minus 180 is equal to 80 minus t so t will be equal to 240 divided by 4 260 divided by 4 which is 65 okay so like this you can solve this question any doubts till now anything fine let's go to the next set let's solve these two questions then we'll take a break okay a graph of pressure versus volume for idle gas a different process as shown in the graph curve o to c represents what o to c can be adiabatic or it can be isothermal okay and we know that adiabatic process has steeper slope that's our option 3 or 44 what if if correct it will be 1 frequency of e m wave doesn't change if it goes from one medium to another fine all right so let's take a small break okay i'll just change the slide if you don't want to take a break you can attempt these two questions so right now it is 12 15 we will meet at 12 13 all right so i can see most of you have already attempted question number 46 and 47 so i'll quickly solve this 46 is about a planet revolving around the sun in elliptical orbit the linear speed of planet will be maximum at we know that the equal area will be swept at equal interval time so if planet is away from the sun its velocity will be lower and closer to the sun its velocity will be higher so it will be highest at a okay so 46 option 2 is correct 47 a horizontal tube of non-inform cross section has radii 0.1 meter and 0.5 meter respectively at m and m for a streamline flow of liquid the rate of flow of rate of liquid flow should be same right it should be same fine this is continuity equation okay let's move to next question now these three okay 48th potential drop across capacitor and resistor is given we need to find the applied voltage so we know that these potential drops are phasors okay so we cannot add them like numbers so they are 90 degree out of phase isn't it so net potential is under root of 5 square plus 12 square which is 13 volts option 4 okay 49th what is the answer okay heat radiated by a metal at a temperature t is e when the temperature increase to 3t the energy radiated will be what so energy radiated is proportional to th power 4 isn't it so if from t to 3t it goes the energy radiated will be 3 raise to power 4 times which is 81 times e okay what about 50th sign here is already answered others the angle of minimum deviation for an incident light ray on an equilateral prism is equal to its refracting angle the refractive index of the material is what mu is equal to sin a plus delta m by 2 divided by sin a by 2 okay so basically delta m is equal to a only which is 60 degrees all right so you can get the value of mu to be root 3 sin of 60 by sin of 30 you will get understood all of you any doubts let's go to the next few questions these ones 51 option 2 is correct here 1 and 1 will become 1 and then not 0 and then not again 1 okay so 1 and this is this can be anything 0 or 1 the output will be 1 only okay so it can't be 1 and 4 and then look at the second one 0 and 1 there will be a 1 this is 0 and yet it will become 0 but there is a not also so it will be 1 that's our option 2 okay 52 what is the 52nd answer others a stationary point source of sound emits uniformly in all directions non absorbing mediums 2 points p and q are at a distance of 4 and 9 meter from the source the ratio of amplitudes of the wave at p and q is what so the ratio of amplitude a 1 by a 2 okay this is actually root of ratio of intensities okay and intensity is proportion to 1 by distance square fine so this will be like 1 by 4 square divided by 1 by 9 square right so you will get 9 by 4 option 3 understood all of you i will move to the next question okay by the way today's class i am going to extend by 15 minutes so we'll end at 115 okay because of the late start we'll end at 115 it's all these questions anyone a gallon meter of resistance 240 ohms allows only 4 percent of main current after connecting shunt resistance the value of shunt resistance is what you know that if you have a shunt resistance it is always connected parallel okay so if main current is i not this current would be 0.04 i not right gallon meter has 240 ohm resistance right so since these two are connected parallel let's say resistance is r over here we have 0.04 i not times small r equals to i not into 240 ohms fine sorry there is a small correction before shunt resistance was connected okay the gallon meter had the current i not after shunt resistance is connected gallon meter has a current of 0.04 i not this is what the thing is from here the current is still coming i not if shunt resistance would not have been there gallon meter would have got i not current but now it is getting 0.04 i not so this is what it means from here the current will be 0.96 i not all right so 0.04 i not into gallon meter which is 240 ohms this is equal to 0.96 i not into small r fine so from here you can get the value of small r small r is equal to 240 into 4 divided by 96 so 53rd the option number is 4 24 right 54 the phenomena in which 4 proton flips is what this again you should know it as a fact that is 4 55 what is the answer 55 anyone 55 this represent an equation of progressive wave t is in second and x is in meter the distance traveled by the wave in five seconds is what for that you need to know the velocity okay so omega by k is the velocity of the wave fine omega is 1 by 2 and k is 1 by 4 so speed of the wave is 2 meter per second okay so in five second it will travel 2 into 5 that is 10 meters actually omega is pi by 2 and k is pi by 4 pi is also there but then it again get cancelled 56 okay this is not in the syllabus leave it these two that विल सेवनाद ध्रफ्वर मप्तिड़िया दिश्व़। ती विल ती विल, मी अद्टीक कब आप औग़ा सेवन भी रहीत क्येगिगाति, का यह खबिम कि लग़्ारी बबअत वो आपुत हैएँ, when it starts from rest is what. So you can see that electric field is uniform. So acceleration will be equal to I will just give you a hint do not need to completely solve it on my end. Q into E is the force this divided by mass will be the acceleration. Mass of the alpha particle and distance is given we can say that it is a constant acceleration V square equal to u square plus 2a into distance 2as so from here you can get the velocity initial velocity is given when it starts from rest so initial velocity is 0 so V is equal to just under root of 2as find the correct answer is option 3 okay can you solve the 58th question now okay prepaid has solved cylindrical tube at both ends has a fundamental frequency of this much in air if 1 further tube is immersed vertically in water the fundamental frequency becomes what okay so we know that if it is open this will be the fundamental frequency isn't it if length is L then velocity of wave is V so V divided by wavelength is the fundamental frequency okay and wavelength can be written in terms of the length of the tube wavelength is L by 2 so this is 2V by L this is the fundamental frequency when both ends are open now if 1 fourth of the tube is immersed in water so it will act like a closed tube alright and the length will be 3L by 4 closed tube and this will be the fundamental frequency so 3L by 4 will become equal to lambda by 4 from here you will get wavelength to be equal to 3 times length right correct so the fundamental frequency now will be velocity will not be changed velocity the medium is same here and there velocity will be unchanged so it will be equal to V divided by wavelength that is 3L so V by 3L so if you take a ratio of fundamental frequency earlier and now I will get 6 so 1 sixth of the earlier fundamental frequency actually here it will be 2L earlier wavelength was 2L sorry about that so this is 2L so when you take a ratio it will be 3 by 2 right so mu not dash the new frequency is 2 third of the earlier frequency so it will be 1 3 0 into 2 260 understood any doubts please ask quickly we will go to the next one then these two questions what is the wings displacement law which tells us lambda into t should be a constant you can easily find out the wavelength received from far away star and multiplication of these two should be a constant that is what the wings displacement law is about okay now solve the 60th question okay with which we have answered others okay the correct answer is 2 only how we can solve this charge deposited on 4 mycloquorum capacitor is what is asked so if I know the potential difference between these two points I will be able to find the charge okay so let me first find the equivalent of these two which is 6 so 6 and 6 are connected in series across 12 so I know that if 6 is connected in series with another 6 this is 6 micro farad and there is another 6 micro farad let me not change the location this the 6 micro farad this one is equivalence of 4 and 2 parallel okay so since these two are connected in series Planck's law is about spectral density of em wave so it basically says that it will be under equilibrium with the surrounding the amount of heat the rate of heat it absorbs will be equal to rate of heat it emits okay in fact Planck's law expression is not in our syllabus itself so it gives you an expression of power emitted per unit area of the body the Planck's law for a particular wavelength okay but it will not tell you it will not let you compare between two bodies two black bodies where wavelength into temperature should be a constant temperature is that temperature for which you know the intensity of or the power emitted is the maximum because different wavelengths will be emitted so wavelength at which the power emitted is maximum that wavelength into the temperature of the black body should be constant this is Wien's Displacement law Planck's law is something else okay so what I was saying is since these two are connected in series the charges will be same so let's say q and q are the charges so I can apply the Kirchhoff loop rules of 12- q by 6 and will be another factor will come in this should be equal to 0 so you will get q as 36 micro coulomb fine once you get 36 micro coulomb you can find out the potential difference between these two points as in across 6 micro coulomb 6 micro farad sorry the potential difference will be equal to q by c 6 divided by 6 so 6 volts in fact you can make out from here also that 12 ohm back raise connected across two similar capacitors so half half it will be divided so 6 volt is the potential difference across these two points and across these two points only the 4 ohm is connected so charge on the 4 ohm capacitance will be equal to 4 into 6 that is 24 into 10 is called 6 coulomb fine so this is how you solve this particular question fine so today I have this much to cover only total 60 questions we have covered today tomorrow again we are meeting I think tomorrow tomorrow is again there is a class so tomorrow we will be covering this is ct 2009 paper tomorrow we will be covering k 2009 paper alright anyone has any doubt till now please type in any doubts alright friends so that's it for today we will meet again tomorrow I will announce the timings in the group sorry for the late start today would not help at times some technical problems but we have covered everything whatever was planned ok bye bye


Hello and welcome to this session in which we would learn how to find the price of a bond. This topic is important whether you are taking financial accounting, intermediate accounting, studying for the CPA exam, or studying for the CMA exam. Finding the price of a bond is important because it also covers the concept of time value of money and the concept of discounting. Whether you are an accounting student or a CPA candidate, I strongly suggest you take a look at my website farhatlectures.com. I don't replace your CPA review course, you keep it. I am a useful addition to your CPA review course. I can add 10 to 15 points to your score by providing you with alternative resources, lectures, multiple choice, true, false, exercises. Your risk is one month of subscription. Your potential gain is passing the exam. If not for anything, take a look at my website to find out how well or not well your university doing on the CPA exam. My course catalog include practically all of your accounting courses and my CPA review courses are designed to align with your CPA review course, whether you're taken Roger, Becker, Gleam or Wiley. I do have those courses aligned. I also have all previously AI CPA released questions for the past 10 years. You can find them on my website with detailed explanation. If you haven't connected with me on LinkedIn, please do so. Take a look at my LinkedIn recommendation, like this recording, share it with other, connect with me on Instagram, Facebook, Twitter and Reddit. So how to find the price of a bond? It's very important to understand what is a bond. What does a bond look like? What is a bond? A bond is a form of borrowing. When a company wants to borrow money, they can go to the bank and ask the bank for a loan or they can go to the market and ask anyone who's willing to give them money, lend them money. That's what a bond is, a form of borrowing by the company. Usually, bonds comes in $1,000 denomination. They have $5,000, but usually we're going to be dealing with $1,000 denomination and specifically we're going to be dealing with corporate bonds. The bond will always have a face value. What is a face value? The face value is how much this bond is worth once it mature. Sometime it's called the face value, sometime it's called the maturity value.  Think if you are looking at a $100 bill or a $50 bill. You would literally see the number 100. You would literally see the number 50 and this is how you know it's $100 or a $50. So the face value is something that's printed on the bond. That's the face value. What's on the face value of the bond itself? There's always an issue date. So when we issue a bond, there's a date. For example, for the bond that we're going to be issuing, it's going to be December 31st, 2022. And the face value for our bond, it's going to be $100,000 face value or maturity value. So basically, whoever have this bond at maturity will get back $100,000. Coupon rate, stated rate or contract rate. The bond will have to pay a certain rate. So when you want to borrow money from people, you have to promise them, you have to tell them, look, give me the money, I'm going to give you your money back, plus interest payment throughout the life of the bond. So you have to tell them, what is the coupon rate? What's the stated rate? And what's the contract rate? How much are you offering? And sometimes it's called the offering rate. So many terms are used for the same thing. For our purposes, we're going to assume this is 8%. 8% means the bond will pay 8%, 8% of $100,000. Well, because you want it, you want to be compensated. Also, you're going to have to have interest payment dates. Okay. The first thing I need to tell you, this 8%, that coupon rate, stated rate, contract rate, this is a fixed amount. Fixed means once that rate is offered, it no longer changes, because this is how much this bond is paying. It's a printed on the bond itself. Notice here, it's on the bond. So imagine this is the bond, it's printed on the bond itself. Also, bonds, usually corporate bonds, they pay interest semi-annually. For example, for the purpose of this bond, we're going to assume it's going to pay interest on June 30th and December 31st. So it pays interest twice a year, rather than once a year. And that will make a difference as well in computing the price of the bond. So that's also a part of the bond. And the bond will have a maturity date. The maturity date is when can the bond holder, the person that holds this bond, can go back to the company and say, I would like my $100,000 back. This is the maturity date. I want my face value. In the maturity date, for our purpose, it's going to be December 31st of 2024. So simply put, this is a two-year bond. So it's a simple bond. But the concept will be the same, whether it's a two-year bond, 20-year bond, 30-year bond. The concept is the same. So those are the basically the main component of a bond. Now also for a bond, there's another thing that we have to worry about. And I kept it separately for a purpose. I gave you some space here to talk about the market rate, the market rate or the discount rate. And I talked about this in the prior session when I discussed how a bond is, when is a bond sold at a premium, discount or par. And what is the market rate? This company here, let's assume this is Adam Company. Adam Company is offering 8%. So Adam Company says, I want to borrow $100,000. I'm willing to pay 8% if you are willing to lend me your money. Well, here's what's going to happen. All the lenders, they're going to look at the market. They're going to look at the market of similar interest rate, similar companies to yours. And you pay the market, they're going to have a market rate. And we're going to have your coupon rate. And remember, I can go with the coupon rate. I can go with stated rate, whatever. So if you are paying 8% and the market is paying 8% and this should be a review for us. If you are paying 8, the market is paying 8, the bond will sell at a par. It means you will get your 100,000 when you try, when the company tried to sell the bond. If the coupon rate, if you're paying 8% and the market is paying 10%, no one will give you the full 100,000 because they can give it to someone else and earn 10%, which is $10,000 a year, you're paying them $8,000 a year. Therefore, your bond will sell at a discount. If your coupon rate is 8% and the market is, and let's assume, let's assume, yeah, let's assume you are, what are we going to change? Let's assume you are paying now, you are paying 12% and the market is only paying 10. Well, in this situation, your bond will sell at a premium. Why? Because you are paying more than what the market is paying them and you have to understand those relationships. Once again, we discussed them in the prior session. Now, what we're going to be learning, adding to this session, the addition is how to actually find the discount price, how to find the premium price. Simply put, how to find the price of the bond. If it's at par, if it's at par, it's you're going to get 100,000. So I'm going to illustrate when the bond sells at a discount, when a bond sells at a premium and how to find exactly that exact price. So we're going to find the price of a bond. So to illustrate this concept, I'm going to be working with the add-on bond. Par value 100,000, they want to borrow 100,000. The stated rate, they are saying we can afford to pay 8%. The market is paying 8, the market is paying 10. And this is the interest dates, June 30, December 31, the bond issued on December 31, 2022, mature on December 21, 2024.  So this is what this bond would look like. It's very important to see it on a graph. This bond is a two-year bond, which is that you're making four payments. We're going to have one, two, three, four. We're going to have four payments of interest. And in addition to the four payments of interest, we're going to get our money back, which is 100,000. The first thing you want to compute is how much is that interest payment? And this is an important formula. You will take the face value times the stated rate, which is 8%, times one-half. Now, why did I compute this by one-half? Because the interest on this bond, as I told you, most corporate bonds pay interest semi-annually. Simply put, the holder of this bond would receive $4,000, $4,000, $4,000. And another $4,000, the last payment. In addition to the last payment, they would receive also 100,000. Now, to value this bond, what is a bond looks like? Hopefully, this is, we're starting to complete the picture and things are starting to hopefully click. The bond, from the buyer's perspective, is a future payments. You're looking at future payments, and you want to find out how much you will pay for those future payments today. So this is the price of the bond. How much will you pay for one, two, three, four payments of $4,000? And how much will you pay for the 100,000 two years from now? Well, guess what? We have to use the present value. We have to discount those payments. Now, how do we use the discount? Well, if you're not familiar with the time value of money, please go to my website and I have a whole lesson about the time value of money. So I'm not going to explain the time value of money in details here. I'm going to show you the application of the time value of money. Okay. The first thing you need to understand is this. Once you go and you want to compute the price of the bond, simply put, once you go to use the tables, you would always use the market rate. Why the market rate? Because whoever buying the bond, they want to earn the ongoing market rate. The ongoing market rate is 10%, not 8%. 8% is what the company is paying. The buyer of the bond, they want to say, I will pay for the bond a rate that's going to consummate the market risk, which is 10%. Now, this rate is the interest rate will be always quoted annually. You have to adjust the interest rate. So if it's 10% annually, I have to divide by two. In other words, when I go to the table, I will use five. Why? Because this is the interest rate is compounded semi-annually. So 5% every six months. It's not the same thing as 10% annually. Again, you can go to the time value of money lessons and I explain this in the tail. I just want to let you know here that you will have to use 5% rather than 10. And although it's a two-year bond, you have four periods because it pays interest semi-annually. Twice a year, that's going to be four. So when you go to the table, I will be equal to five and will be equal to four, period four and I5. Now, what we're going to do, we're going to discount those two components. First, I'm going to start with the 100,000. The 100,000, I'm going to be getting this money only once. It means this is, I'm going to have to find the present value of a single payment. What do I do? I'll go to the present value table and this is the present value table. This is make sure you are using present value of $1, present value table. My interest rate is 5%, 5% is right here and my period is four, four period. I'm going to go across and I'm going to find out the rate is 0.82270. Okay, this is the rate, 0.82270. What does that mean? Simply put, my 100,000, this 100,000 right here, this 100,000, I'm going to take this 100,000 and I'm going to multiply it by 0.8227, which means the 100,000 alone, I'll pay for it 82,270. So 82,270 is the present value of the 100,000. So this is how much I'll pay for this, for this 100,000. If I buy it today, this 100,000 for 82,270 and I wait two years, it's going to earn me 10% if I get 100,000. Now I'm not only getting the 100,000, I'm also remember I'm getting four, $4,000. Well, I'm getting the same amount repeatedly. I need to discount the same amount repeatedly. This is called an annuity. Well, guess what? The $4,000 is my annuity. Annuity is a series of payment. I'm going to be getting those series of payments. Again, how much will I pay for those series of payments? Well, depending on my market rate, my market rate is 10 annually. It means 5% semi-annually. Well, I have to go to the present value of the annuity table. So I'm going to go to this table here. Present value, remember, making sure you are working with the right table, present value of an ordinary annuity. Again, 5%, four period and the factor will be 3.54595. I'm just going to round it to 3.5460. And that's going to give me 14,184. Now I'm going to compute, add up my the present value of the face value, which is 82,270. The present value of the payment, it's going to give me 96,459. And this is my price for the bond. And this is a discounted price. And hopefully you knew it was a discounted price from the beginning. And the reason you know it's, you should know it's a discounted price because what the company is offering 8% is not compensating the market. The market is paying 10. So no one in the right mind will pay you 100,000. Therefore, the bond sells at 96,459. And this is how we found the price of the bond. And if you get something more than 100,000, you should know your answer is incorrect because the bond should be discounted because I'm not paying enough of interest. Let's change the scenario. And let's assume we are offering 12%. The market is offering 10. Immediately before you do the computation, if you're trying to borrow 100,000, you know immediately you're going to be getting more than 100,000, the bond will sell at a premium. In this example, it looks something like this. We're going to have 1, 2, 3, 1, 2, 3, 4. And since you're paying 12%, it means the buyer of this bond will get 6,000, 6,000, 6,000 and 6,000. So we're going to discount this annuity. And we're going to have to discount also the 100,000. Remember we have to adjust the market rate. The market rate is 10% annually. Since we are paying interest semi-annually, we have to divide the rate by 2. Again, if you're not sure why do we do this, go to my time value lessons and I will explain this in detail. So simply put, I'm going to do the same thing. The first thing I'm going to take my 100,000, go to my table, to my present value table and 5% for period. And obviously it's the same amount, 0.82270, same amount as the prior time, 0.82270, because we did not change the market rate. So I'm going to get 82,270 for the face value of the bond. That year 4, I'm going to be getting this 100,000. Today, this amount alone is worth 82,270. Okay. And if you want to do the math, you can take 82,270 and make it earn 5%. Keep that money, make it earn 5%, 5%, 5%, 5%, you will see you will get 100,000. Now the second thing I'm going to do, I'm going to take my 6,000, it's an annuity multiplied by the present value annuity factor. I'm going to go to my present value and I'm going to go to my present value annuity factor, 5% for period, and that's equal to 3.54595. Again, I'm going to round to 3.5460 and I'm going to get 21,276. Now this is the present value of the face value, the present value of the payment in total, my bond is worth 103,546. My bond, as I predicted from the beginning, it's sell at a premium, indeed it's sell at a premium. The premium is the 3,546 and this is how to find the price of the bond. And in this recording, that's all what I wanted to show you, not how to read the bond, not what does the price mean, whether it's a premium discount par. I just wanted to show you mechanically how to find the price of a bond. If you find this recording helpful, please take a look at my other resources. Again, I don't replace your CPA review material. I am supplemental. I compliment your material. Add me and you'll add 10 to 15 points on your exam. Your risk is one month of subscription. Once again, I do have resources for other CPA review courses, Wiley, Gleam, Roger, everything is organized to match your course. And I do have access to your AI CPA previously released questions. Good luck, study hard. And of course, stay safe.


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I am Dr. Shivram, consultate and head of transfusion medicine at Manipal Hospital Bangalore. As all of you know, the plasma therapy for covid patients is the in thing currently. And this is being offered to patients as a good supplementary treatment to the existing drugs and other modalities. Well, let us understand what is convalescent plasma or covid plasma. The convalescent covid plasma is plasma collected from a patient who has recovered from covid 28 days after complete recovery of symptoms. So how does this benefit a patient? The very fact that this patient has recovered from covid means that he has probably developed antibodies which destroyed his virus. So we now want to collect this plasma containing antibodies and give it to another patient affected by covid. But the challenges here are first determining whether there are adequate quantities of antibodies present in the plasma for which we use the help of our microbiology department. We first determine what is the quantity of the antibody present in the donor that is the recovered patient. And then we collect the plasma from the donor and give it to the patient. That's about the source of convalescent plasma. A few words about who can donate convalescent plasma. The donors should have recovered from covid-19 infection. The age of the donor should be between 18 to 60 years. Males and Nalli Gravda females that is females who have never been pregnant can donate convalescent covid plasma. Weight of the donor should be more than 50 kgs and the donor should meet the regular blood donation criteria. According to the patient, who are the patients who are likely to benefit from this plasma. It has been shown that patients who are suffering from moderate disease are likely to benefit from plasma therapy. Patients who have mild disease, there is no indication. Patients with severe disease who are already on ventilator or who have gone into multi-organ failure are unlikely to benefit from covid plasma therapy. Therefore covid plasma therapy should be offered to patients on moderate disease who have increased in oxygen requirements despite use of steroids and other drugs which are given to cure this condition. The plasma is collected by a procedure known as aphorosis. Now this aphorosis is a very simple procedure where we can collect the particular component required. Here we are going to collect plasma and the time for this process will be around 1 hour. So mostly in 2 hours the entire procedure process will be completed. Next donors commonly feel that what will happen to me if you take away my antibodies. Natural apprehension for any donor who has just recovered from covid. Let us understand that any adult patient with about 5 litres of blood and 3 litres of plasma in his body, we collect only 400 ml of plasma. That means you are still left with more than 2.5 litres of plasma with adequate antibodies in you. We do not take all of it, we only take a small portion of the antibodies. The second doubt which patients have is that slowly my antibody levels will go down. So what will happen to me if I have a reinfection? Please understand that in the event of a reinfection, your body has got a type of white blood cells called the memory B cells which can produce antibodies very quickly in the event of reinfection. Though Karnataka has recorded more than 3 lakh covid-19 infections and more than 2 lakh people have recovered so far, but still only few hundreds of people have donated to Karnataka. So we receive around 30-40 requests from across Bangalore daily, but we are able to honour only 3-4 requests till now and hence I request common public to come forward and donate convalescent plasma in good numbers. You are therefore still protected against covid, against the same strain of covid even after donating plasma which is the source of antibodies to cure covid.