Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

Posts posted by pulkit

  1. I don't think you'll predict 3d9 4s2 for copper, since fully filled sub-shells are very nice things. They have less energy amongst other things due to symmetry. Due to symmetry they have a high exchange energy which is always nice. Half and fully filled are always preferred.

  2. Given their complex electronic structure, they can be stable in more than one configuration, however in general there is a single most stable state, for other you need to spend energy. Since as shell size increases, energy differences go down, the energy difference between two ionic states may not be much and stability persists. Plus, having empty d orbitals always helps.

  3. Thats equivalent to asking how does the battery know wether there is an open circuit or not.


    As I mentioned, looking at it as an equivalent circuit with no gaps between elements (such as the one between the primary and secondary coils) and replacing them with approprite impedences, it becomes exactly equivalent to the battery situation.

  4. Just to add, we use binary because we know how to make devices that have two stable states {0,1}. If on the other hand we could get basic components that had 3 stable states, it would at times make more sense to use base three.

  5. here`s an interesting one.


    Imagine a transformer pluged into the main without a load on the secondary' date=' it barely gets warm and will happily stay that way for days/weeks etc...


    now short out the secondary and it get quite hot quite fast, maybe even to the destruction of the device.



    now split the transformer into 2 halves, we have our primary plugged into the mains and it`s quite happy acting as a simple AC electromagnet :)


    why then should it get hot if I bring the other half (the shorted secondary coil) near to it?


    How does it "Know"? :))[/quote']


    This is the famous "open circuit" and "short circuit" test of the transformer.


    When you have no secondary, it is equivalent to an open circuit, there is only leakage current in the primary, no heating whatsoever.

    When the secondary is shorted, the current in primary goes up like crazy (when you perform short circuit test, you actually apply only that much voltage which gives you a current saturation in secondary, on calculation this turns out typically to be less than 20V) Even with voltages around 15V, you will get huge currents in secondary, depending upon the constants of the transistor. If you apply 220V or 110V in a short circuit, you are bound to burn out the device, too much current, too much heat.


    You can analyse the equivalent circuit of coupled inductances to have a clearer picturer of "how it knows".


    When we did short circuit tests, we were strictly told to restrict ourselves to less than 10V at input and even then we were getting huge current ratings. Also, the test was to be performed in minimum time possible , hopefully 4 to 5 minutes to avoid excessive heating and damage to the device and to ourselves.

  6. Gcc' date=' G++, G77 and several other compilers are free. I have only ran into two programs that cost on Linux. So your argument is no good there. And Linux is a totally diffrent OS. It is not designed to run Windows applications just as Windows is not designed to run Linux applications.


    Wine is a optional program to allow you to do this. It's not required. Also just type 'wine' at the console it will create a profile for you then just do ./program.exe or double click on it's icon or do wine program.exe in the console. Wine is not difficult to use at all.


    Sorry but it seems your used to how easy Windows is. Your arguments are no good in my opionon. :embarass: Linux is a bit advanced in some areas but once you master it you will love it. Linux also allows you to have more control over your system. I mean it is open source.[/quote']


    Mandrake cd4 is not free, it has several packages that a programmer needs.


    LEDA is not free.


    AS and when I need a new library for c++, i am certain I'll find that it wouldn't be free.


    As "advanced" as linux may, as often as I may have to work on it, I still do not find it as easy to use as windows. I can not imagine a day when a substantial percentage of home pcs run on linux.

  7. What is being discussed so far is numbers in base 2.

    However using binary ,i.e., the set {0,1}, a huge variety of codes can be developed. Some of the more popular ones you can find easily are BCD, grey code, XS3 code etc. These are all for encoding numbers.

    You then have ASCII codes for characters.

    AS situations demand you can come up with a code for practically anything, depending on what code you use, you will build your particular hardware to interpret it.

  8. You can run Internet Explorer on Linux with Wine. :)


    See thats the entire point I wanted to bring out. I work on linux only because I do not wish to waste time acquiring g++, gcc, and libraries for windows and that for those libraries my college won't pay, I'd be paying myself (Remember that lots of stuff is not free even on linux)............in no way do I currently find linux to be "superior"to windows. After working in windows I find lots of software not upto the mark in linux - typical example - yet to find any cd writing software that will match up to nero 6.


    And also, my attempts to use wine (the man pages are not too helpful) have been futile till this point, so i decied to give up on that idea. Easier solution -- log into windows !

  9. I was faced by this windows v/s linux debate for quite some time about 2 or 3 months back. Eventually I HAD to install linux on my pc because my college department (comp science) works on linux. I use it primarily because all the stuff for my programming needs is available in the labs solely on linux. But at home, I try my best to find equivalent windows software.


    What I have realised in these few weeks is that anything that you can run on linux you can easily find and INSTALL on windows. The same is not true the other way around. Installing stuff on linux for inexperienced users and sometimes even for experienced ones is a major headache. Of every 9 or 10 packages you try initially, you would probably end up successfully installing just 1 or 2 if you get lucky.


    For all its openness and utility, I still do not find it as user friendly as windows. And also, as far as stability is concerned, the first time I experienced a crash on windows xp was about a year of usage. In a short span of 3 months, I have experienced system crahes and hung pcs on fedora core 2 and mandrake 10 five or six times. As a result, I still think of xp as a far better os. As far as threat of viruses are concerned, I think you can protect yourself fairly well with firewalls, anti viruses and security updates.


    A major problem I also face is learning the konsole commands. Its absolutely crazy trying to do that, there are enormously long man pages that are sometimes impossible to read. The learning curve is very steep, but frankly work efficiency does increase, you can in general achieve the same task with fewer key strokes in linux as compared to windows.


    If you sit on a large LAN, then too linux can be fun. I as a novice could pick up bits and pieces of networking fairly easily. But the fact remains, I always find windows more comfortable to work in, though I continue to strive to learn linux.....I write this post whilst I am logged into linux....... (firefox --- not as good as ie as far as i am concerned :( )

  10. Hey pulkit, doesn't India have like over 20 languages that are considered to be major ones? Or then I was just asleep during my geography lessons. :)


    Yes, I think there 18 official ones in the constitution. The number of languages that you can experience in the country is however larger. Each state is typically characterised by a different language , and within each state one can find tens upon tens of different dialects. Quite a lot of diversity.

  11. well I have no data on Francium' date=' so I`ll use Cs instead if that`s ok?


    using Paulings scale of electronegativity to determine percentage of Ionic Charecter.


    Cs = 0.7 and Cl= 3.0 a difference of 2.3


    K = 0.8 and F = 4.0 a difference of 3.2


    as a percentage 2.3 = 74%

    and 3.2 = 92%

    I`de infere from that KF has a stronger bond than CsCl.


    I could be wrong, I`m very tired today. Zzzzzz...[/quote']



    A factor that governs stability of compounds is the size of ions, by size I mean relative size. Two ions comparable in size would be more stable in a bond than one big and a small ion. That is why if you take NaCl and mix it with KF, you expect to get KCl and NaF.


    As far as CsCl goes, I don't think you can simply look at difference in electronegativities and comment on its bond strength - its more of a rough estimate (especially since it will also depend on which scale of electronegativity you chose to use)

  12. nice dog pulkit!


    nice to see you keep CMD on there!

    and norton' date=' good good, i prefer the windows media v8, but thats just me :)


    also, looking at the time.... what were you doing on SFN at 00:07 (your local time)!?[/quote']


    I am most active at night (working days are no exception ....) :)

  13. English , Hindi : Read, write and understand


    Punjabi (and variations like Multani etc.) : Can mostly understand, and speak with some erorrs (btw they are all regional languages common in North India and in Pakistan)


    French : Learnt for 7 years at school, but I think I've forgotten most of it by now, never got a chance to practice ......been nearly 4 years now


    Japanese : Tried it out once, bit too difficult, left it after 10 classes....


    What I hope to achieve --> Learn to write and read Punjabi

  14. Being "clear" (or transparent) is usually because the electrons don't have free energy levels to rise, and then to drop down from to emit light, as you have heard.


    If thats true then I think you have in essence answered all the questions you posed.

    Metals have typically free energy levels for electrons to jump to. Glass being the 3-d covalent solid it is, its hard to imagine free energy levels in there. The example that pops up in my mind as soon as I think about this question is diamond v/s graphite. Excellent example because it illustrates that transparency is not inherent in atomicnumber or molecular structure but also in the spatial arrangement of the same. But that would also have me believe, that in theory it should be possible to create some sort of structure with metal atoms as well that should yield transparency - this could very well happen when metal is beaten into extremely thin sheets. As far as liquid metal is concerned, I don't know if you have ever seen any first hand -I think everyone should- but when its liquid all you see is red or yellow, hard to say at that stage wether it is opaque or transparent, even glass that hot would glow. I must say thus that I am not truely convinced that all liquid metals will be opaque.

  15. Using onlt basic differential calculus you can easily graph most such functions by hand. Curve tracing is one the most interesting aspects of calculus as per me.


    And, yes such functions often give you vertical and horizontal assymptotes, that you can determine using some concepts of limits.

  16. Cataloguing theorems makes little sense to me.

    You'll have all sorts of trouble landing at a universle enumeration, and then lots of time wasted to correlate these numbers to theorems (in proofs of other results etc.)

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.