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pulkit

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Everything posted by pulkit

  1. 0^0 is just undefined. You end up with indeterminate quantities when while taking a limit both numerator and denominator approach 0. But then too there is the easy way out of applying L'Hospital's rule and getting a value. Indeterminate merely implies that it may have different values in different situations.
  2. Simplest way out would be to use your 12V bulbs with the 18V battery. If you caonnect them as it is they will fry out no doubt about that, connect in between the battery and the bulb a potentiometer, adjust its value till you get a 12V output voltage across your bulb. You can get small potentiometers very easily, and then adjust them by tightening a nut. If you do this, you would have in essence attached a regulator in your circuit, if you increase resistance of potentiometer even further, then voltage will drop and bulb will glow less, if you reduce resistance, glow will increase but beyond a point (12v) your bulb life will go down rapidly. Use a multimeter to observe voltage while you set resistance and you should be done.
  3. pulkit

    infinity?

    Our exsistance is fundamentally flawed ?? :-S How on Earth do you reach that conclusion ?
  4. pulkit

    Cell Phones

    There was a front page news item a couple of months back that said cell phones lead to drop in sperm count, if you carry them in your pocket. There is radiation emitted and studies showed a reduction upto 30%.
  5. Solutions are not always w/w, they can be v/v as well (Eg. Ethanol solutions are always v/v) when the solute is a liquid, also there are w/v solutions. 7% glucose and 20% NaCl are most probably w/v solutions. w/v is one of the most popular ways to keep track of concentration, its also called strength of a solution.
  6. What battery do you have ? A 24V supply or 18V ?
  7. pulkit

    Java

    I would believe that spending half a year learning java would be non sense. It is just a tool - a programming language, just learn the basics as quickly as you can, then a reference manual of functions should be enough. I started with a working program that had input and output in it. The fact is that if you want to utilise the power of java, you just can't waste a month learning how to take input output and what sorta variables are supported in java. A very good reference manual I bought was "Java: Complete Reference" by Schildt. You just can't waste time learning programming languages, it is more important that you know how to write efficient programs. I have myself programmed in 4 different languages in the past 6 months (java, c, c++, and since last week assembly) if I sat down to get into details, I'd get no work done.
  8. HCF GCD and GCF are all the same thing
  9. pulkit

    Java

    Java can't be run as a .exe because it is best to keep it platform independent. Thats why you make .java files which can then be compiled on any platform. If you made .exe you won't be able to run the files on many systems. For a good site on it, just go to the sun site, they have lots of good content there.
  10. Let m=6 and n=10. Your formula would use b=-1 and a=2, hence minimum value turns out to be 12. But if increment was in units of gcd, then 14 should be possible, which is clearly untrue. Whereas psi20's formula of gcd+lcm-sum would have this lowest value as 16, beyond which every number at interval 2 can be made. I would have believe that psi20's formula for least value holds (maybe it can be proved by double induction on m and n) and increments are equal to gcd of the two numbers.
  11. Reminds me of tour de france ) As far as school of fish are concerned, they tend to stay in schools so that its really hard to catch a single individual ( Its even hard in an aquarium forget open ocean ). The school tries to move as a single fish, so there may not be a single fish leading it but perhaps a bunch of them. How they manage to coordinate ? I have no idea
  12. Interestingly enough this is the exact aircraft I was mentioning. I had seen it on television. I can't figure out whether this craft was unmanned or manned from this website. The prototype on television, didn't have a pilot, it was computer controlled.
  13. What are the conditions for stimulated emission to occur ? Would it be possible in this case to create a population inversion ?
  14. I don't think thats been done yet. The one very efficient solar powered aircraft I know of is a very high altitude plane which is un manned and would probably have only one of two uses : a) Meteorological Data collection b) Spying
  15. OOPs !! Made a massive mistake, it wasn't a Nitrogen-Helium laser, it was a Neon-Helium one. I am really sorry ,I had a memory lapse of sorts ... (
  16. I knew when I had to give a viva ....lol ! Unfortunately I don't remember now, you can always use google. Its not all that difficult a concept. Again it uses partially silvered mirrors and stimulated emission. Also its quite a powerful laser. I performed a single slit diffraction experiment with it.
  17. Fuel cells are an excellent option. They powered the apollo mission to the moon (I mean all the power inside the shuttle) I know that a car based on these has also been built, but the problem is that Hydrogen is dangerous to store and the technology at present is kind of expensive. Cooking gas and natural gas though fossil fuels are a lot less polluting than petrol or diesel and are used extensively in terrestrial vehicles. I don't know whether they have been used in planes or boats.
  18. There are Nitrogen - Helium lasers. Gases are in ratio 3:1 or 1:3 (don't remember exactly) I know coz I used one. It gives out red coloured light. Frequency is somewhere b/w 550 and 600 nm (again don't remember exactly)
  19. Boats already have wind to support them. I do therefore think that you can optimize energy usage on one appropriately and it should be possible to build one. Solar panel powered planes, I think you can have some high altitude un manned aircraft that have this feature. You need battery backup for take off and landing when you won't necessary have solar energy. It has therefore already been done.
  20. I am thinking stimulated radiation, because this sounds awfully similar to it. Simulated radiation is the phenomenon behind the generation laser beams itself using half silvered mirorrs, and causing a population inversion in a group of atoms.
  21. pulkit

    infinity?

    A little bit that i'd like to add to YT's post as a footnote is that the concept of infinity we know and use is based on comparisons and comparibility. In essence you can define infinity for any set that has total order under a particular relation. Eg Real numbers under the total order > (+infinity) or <(-infinity). You could go on and define infinity using any other set and a total order relation defined over it.
  22. I voted yes. The immediate benefits of spending money on other things are much greater. Space exploration at present doesn't seem to hold any distinct advantage for the human race. (I say this as a comparison of the cost:usefulness ratio)
  23. pulkit

    infinity?

    Time needed for a capacitor to fully discharge across a resistance R.
  24. I was just giving an example. If all you wish to do is measure the number of mols, the easiest way would be to just weight the gas.
  25. Kindly post this formula The problem (for the general case) definately seems non-trivial to me.
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