Answer key for AIEEE 2012 Online Exam held on 12th May

[ketansharma]

Since AIEEE and CBSE have been lazy enough to put only the questions and responses of the students who gave the online version of AIEEE, this thread shall help students (specially those who gave their online exam on 12th May) to evaluate their performance via discussion of answers...Students are free to ask questions from online exams held on dates other than 12th May too...Please feel free to put up questions from the online exams and they shall be answered so that in a certain period of time we'll have an authentic answer key to the online exams which even the coaching institutes haven't put up...!!

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P.S. I also gave my AIEEE on 12th May..

[kenprakash]

Hello, I appeared for AIEEE on 12th may. I see that no one has uploaded question paper so I am uploading mine. Please post the answer key as soon as possible and also tell me the expected marks and rank. Thank you.AIEEE 12 may.pdf

[ketansharma]

@kenprakash Thanks for uploading the question paper..now it is ascertained that the questions were indeed in random order..In fact when I compared yours and mine I found out that even 1/2 questions are different for the exam held on the same date!!! My internet connection sucks and prevents me from uploading anything hassle-free so right now I can't upload my own question paper..but I'm try to find out a suitable PDF-Word converter so that I can copy-paste questions here...and then there answers...please if you get one help me for the same..
Thanks!

[ketansharma]

*I'm trying *their answers *help me regarding the same

waiting for results screws one's grammar...

[kenprakash]

ketansharma - i cant help you regarding the answers as ive forgotten most of it ! But i can tell you some of their answers. Can u plz help me with the solutions of the following questions - Q4,16,17,27 . Thanx

[ketansharma]

Q.4 Physics (Magnetic effects of current)
Sol. Since wire A is infinitely long, magnetic field due to A, (Ba) = (Ia)/2πr
(Where Ia is current through A and r is the distance b/w A and B in this case)
Now Force on B due to A is F = Ib(Lb)*(Ba) (Where Lb is length of B, Ib is current through B)
Put in the given and answer comes out to be 8*10^(-5) N



---------- Post added at 08:26 PM ---------- Previous post was at 08:22 PM ----------

Q16 needs a diagram, I'm sorry can't explain that without it

[ketansharma]

Q17 Since the sphere rolls in first case, potential energy is converted into Kinetic Energy of translation as well as rotation, i.e.
mgh = 1/2mv^2 + 1/2Iw^2 ....(1) (where m is the mass of sphere, v is final velocity of its COM, w is angular velocity, I is the moment of inertia)

In the second case it only slips down so potential energy gets converted purely into Kinetic energy of translation and we know that here final velocity = 5v/4
therefore, mgh = 1/2m(5v/4)^2 = 25/32mv^2 .... (2)

substituting (1) in (2) and putting w = v/R (R being outer radius of the sphere)
we get 9/16mR^2 = I
now we can put I = mX^2 where X is the radius of gyration
X comes out to be 3/4R

[ketansharma]

Q.27 is one of the interesting physics questions of AIEEE 2012, here's my view on it
For a conducting sphere, we know that capacitance is given by C = 4πR ...formula (1) (where R is the radius of sphere)
putting C = 1 we get R = 9 * 10^9 m (MUCH MUCH MUCH larger than the radius of earth which is given in the Q itself to be 6.4 * 10^6 m)
That means both of the statements are false..!! :p

BUT BEFORE JUMPING TO THE CONCLUSION...we must realize that earth is not a perfectly conducting body..so formula (1) apparently can't be applied..(mind you earth is often assumed to be a conductor in many cases (google it), but clearly AIEEE people don't want us to think that much deeper since no such option is there that says both the statements are false..)
now beyond this i have no idea how they want us to calculate the capacitance of a non conducting spherical body without the knowledge of its dielectric const.
if you find the answer to this question do inform me....
cheers

[veliclaptore]

I saw the question paper. looks a bit tougher than offline . k anyways i can help you in the chemistry section if you like.

[ketansharma]

@kenprakash Sorry I didn't read it carefully..In Q 27 clearly the first statement is true and the second statement is false..sorry once again
@veliclaptore I'll be grateful if you could just tell us the correct answer no. as per this question paper..no need to mention the complete solution (unless and until someone asks for it of course! ^_^ )
Thanks once again..feel free to ask any question..I'll try my best to answer it

[ketansharma]

If rumors are to be believed then the result shall be out by 9th June

[bala05]

what is the answer for the 1st question?? is that correct?? and i think the answer for 7th question is 1st option...

[kenprakash]

thanx !!! 1 more thing, whats the answer of 16 ( not the solution)

[veliclaptore]

how do you short a battery?

[kenprakash]

@bala05 answer to phy questions which im sure -1d,3b,5a,6b,7d,8c,9a,10d,12b,14a,17a,20d,22c,23b,24b,25b,26b,28d,29a,30b
corrections,if any, r welcome .
If ne 1 is sure of even some of his answers, he or she is welcome to post them here.
Thanx