<p>Since there are so many of us preparing for these "imp" exams, I thought we start are very own question bank!! (Maybe akash can request his publisher to print it :))</p>
<p>anyway, we all know that the board exam papers always have one or two 'unusual' questions which are genrally more difficult than the rest of the paper. Lets try and collect all those cool questions, which will probably help us prepare for our exams better. </p>
<p>Feel free to add to the compilation.
Questions from all subjects are welcome.</p>
<p>some FAD theory there is. my book had this thing about how the author was honored to study under the proponent of FAD theory, so that's how i remember. of course, i don't remember the theory itself :p</p>
<p>Physics
[ul]
[li]A series circuit containing two pure elements has the applied voltage and current given by E=200sin(100t+45) and I=4cos(100t+15). Calculate the value of the elements. (I mean calculate R, L or C whichever is applicable)[/ul]</p>[/li]
<p>And remember post only questions which according to you are of a higher difficulty level, yet they have a possibility of coming in the board papers</p>
<p>gosh the intl board is getting totally indianized. more than a quarter of the posts on the intl board thanks to the indian post. of the threads on the top, there's the indian post, prep for cbse and aieee, bjp vs. congres... just wow</p>
<p>arent we indians doing the same thing to the whole world?? :)
invading and taking over the world. Make sure tht ur flight to the u.s has a layover in london. it will tell u who rules who these days..</p>
<p>But seriously, this is like a sample CBSE question :D I remember last year in AIEEE there was a question which went something like this -
[quote]
Hitler's army went atop [some European mountain range] but they couldn't fight. It was not because of the extreme cold, but because the buttons to their coats, which were made of tin, turned into powder! Explain why?
<p>Hitler's army went atop [some European mountain range] but they couldn't fight. It was not because of the extreme cold, but because the buttons to their coats, which were made of tin, turned into powder! Explain why? </p>
<p>tin changes structure, crystalline to amorphous, low temp. low energy--> not sufficient for crystalline structure... is that it?</p>
<p>
[quote]
Hitler's army went atop [some European mountain range] but they couldn't fight. It was not because of the extreme cold, but because the buttons to their coats, which were made of tin, turned into powder! Explain why?
[/quote]
so like, their stuff just popped open?</p>
<p>isnt the crystalline state representative of lower energy? I think Phase transformation could be due to the corresponding rise in entropy. (Maybe)9</p>
<p>But if tin is oxidised to something amorphous as gandalf claims then it probably has nothing to do with the energetics of phase transformations.</p>
<p>(ps - phase is probably not the right word to use here but th correct one seems to evade me at this moment)</p>
<p>Tin exists in three allotropic forms
1)grey at low temp
2)white at moderate temp
3)rhombic at high temp</p>
<p>grey tin is the least dense . White tin converts into grey tin at low temp and the latter being very brittle, crumbles into powder. This is called tin disease/tin plague/tin pest</p>