Rishi

I have been thinking about this. Why is it necessary that work done by/on an isolated system is zero?

Suppose, we have a thermos flask. It, instead of solid walls, has elastic rubbery walls that are still adiabatic. Now, if a gas is kept inside and the gas tries to expand, will no work be done? Assume that the pressure inside > pressure outside, say it is vacuum outside. So w is not 0, v is not 0 and as Q = 0, we can safely say that delU not zero.

Am I correct?

I am sitting for JEE Main 2014 to be conducted by CBSE and I already have applied online. I have successfully uploaded my information and photographs (well within the size limit) and have paid the fees. It showed "Your application has been submitted successfully". I also reviewed my application and everything seemed perfect: the information as well as the scanned photos.

But, when I opened the Acknowledgement Paper (which they give after you've paid your fees), I found that only parts of my photo and signature have come in the Acknowledgement Paper. The thumbprint, despite being larger than both the photo and the signature, is perfect on the Acknowledgement Paper.

However everything on my application is perfect...otherwise the system wouldn't have accepted it right? I have kept my photos well within the limit of size but i am shcoked to see this on the Acknowledgement paper.

What I want to know is, will the Acknowledgement paper affect my Admit Card in any way? You must understand I have checked it 5-6 times, every thing is PERFECT. My application is perfect, but my acknowledgement paper is not. Will I face any problem due to this?

I have already sent an email to CBSE and they told me time will be given to candidates in Jan, 2014 to correct/modify their application. But there's nothing to correct: it's THEIR technical fault. Besides, my application is impeccable, there the photos have come and been uploaded beautifully. I KNOW I have kept within size limits but this thing is a worry for me.

Please answer. Also they are not allowing multiple application as then there will be loss of candidature. Again, why would I apply again? There's nothing wrong on my part!

Acid hydrolysis of 1 mol of an organic compound yields 1 mol ethanal and 2 moles ethanol. Find the organic compound.

A meter scale made of steel gives correct reading at 10 degree Celcius. What would be the correct distance between two consecutive centimeter markings on this scale at 30 degree Celcius? A brass rod measured with the help of this scale at 30 degree Celcius is found to be 5m. long. What would be the correct length of the brass rod at 10 degree Celcius? (coefficient of linear expansion for steel is 12 x 10^(-6) per degree Celcius and for brass it is 18 x 10^(-6) per degree Celcius)

The Indian education ministry has decided common engineering entrance examination. According to you, is the decision right or wrong? What I want you to focus it:

1) Changes in syllabus for IIT-JEE : Obviously the degree of difficulty for IITJEE will lower as the common engineering entrance examination will have to be something between the hardest and the easiest engineering papers.

2) Will the IITs still get the best brains of India? Or if the difficulty decreases, then would not the student quality decrease?

Basically it's winter now and I am having the sensation that I'll catch the cold tomorrow - my nose is not drippy but you know, there's something about the throat that tells you you'll have a cold. Any way in which the cold can be prevented? Does this mean I have already caught the cold? If so, then please mention ways to cure it. I don't want to run to the chemist's. Please tell me ways in which I can cure the impending cold. Thanks in advance. The most effective way will fetch you 10 points!

If f(x) = x^2 / x and g(x) = x then f(x) = g(x) Is it true or false? Why?

AX is a temple. A is its top and X is bottom. From P due east of X angle of elevation of top A is 60 degree and from another point Q due south of X the angle of elevation of same point A is 45 degree. If distance between P and Q be 100√3 m, find the height of the temple.

Please answer this question. Actually the main prob is I can't locate Q. What is meant by "south of X"? I will be grateful if you also attach the drawing so that I can know how to locate points when it is said south of something or north of something.

Thank you. Best answer with diagram and correct ans. gets +10 points.

We actually have the term in our text books in connection with Mendelism but I can't understand head or tail what the book definition states : Alleles are contrasting pairs of different characters situated in the same locus of a chromosome." In the other books, I find "Alleles are the different expressions for a single factor eg. if a factor is height, then the 2 alleles are for Tall (T) or Dwarf (t). When an organism possesses 1 allele [mind you, it's written in the book "1 allele" and not 1 pair of identical alleles], it is homozygous and if there are 2 alleles, it is heterozygous."

Well, none of these definitions is suitable. Please explain to me in detail with simple examples what this term refers to.

If x+y+z = 0 then prove that x (y - z)^3 + y (z - x)^3 + z (x - y)^3 = 0

I am in class IX and I want to take part in that fair. But my target is simply diffused and hence, I do not know how to begin with. I am a lover of science but can you plz give me certain ideas, realting to physics, chemisty, maths or technology, it can be any, but I really need a plan to begin with. You need not have to tell me all I have to do, coz I will have to find that out. Just give me a hint about what to begin with. Like, what has not been discovered or invented yet, something like that.

1. If b / (a+b) = (a+b+c) / (2a+b+2c) = (a+c-b) / (b+c-a) then prove a / 2 = b / 3 = c / 4 .

2. If (5a-3b) / a = (4a+b-2c) / (a+4b-2c) = (a+2b-3c) / (4a-4c) then prove 6a = 4b = 3c

3. If a² + b² + c² = 36, x² + y² + z² = 25 and ax + by + cz = 30 then find the value of (a+b+c) / (x+y+z)

4. If 2a / (4a+b) = (a+6b-3c) / (7a-5b+3c) = (3a-4b+7c) / (3c+10b-5a) then prove a:b:c = 1:2:3.

Thanks in advance

There's a sentence: Put it down.

We need to transform the active sentence into passive sentence. Will it be wrong if I say: It is to be put down (by you) ? If so, please explain clearly. I say it with this logic:

1) Subject of active sentence, You, becomes an object of the passive sentence.

2) In passive sentence, "to be" is compulsory and it is used by me.

3) Object of the active sentence, "it" is the subject of the passive sentence.

I live in Kolkata in West Bengal state of India. But that's not a matter of great importance, just a piece of information only. I wish to know what must be my abilities to earn a decent degree in Nuclear Physics, the highest of course. I am the first boy in school, for you to know just. Please inform me of the various exams I require to pass, in order to reach the apex. Also, please tell me what abilities I need to contain, and also just a gist of the subject.

Please include the names of websites also which may fulfill my wants. Thanks in advance.

Prove that, in any triangle, the orthocentre, circumcentre and centroid lie in the same straight line.

In triangle ABC, BI and CI are the ext. bisectors of angles ABC and ACB respectively.A,I is joined. Prove that AI is the internal bisector of angle BAC. Thanks in advance.

1. If Cos^4θ - Sin^2θ = 2/3, find the value of 1 - 2Sin^2θ.

2. Factorize: x^2 - (x - ab). (a+ b)^2

Please tell me the proper site where I can go to download. Specially plz don't tell me the site where I will get Bengali edition papers.