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JEE_Mains_2015:: Doubtfull Answer Key

Hi guy's , as we see there are mistake in 2/3 questions of JEE MAINS 2015 , Will anyone going to report in CBSE ? CBSE will cost 1000 Rs for each Questions.....

Also what is time constrained for Challanging Answers ... ? what are your views ... which which question do you found have wrong answer's ?

Please discuss.. Thanks!

Karan

Note by Karan Shekhawat
2 years, 1 month ago

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CBSE is stupid. Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal Really they are Foolish....

They are making paper from 3 years.... and what we know ... they still not understand how to make paper ..

They Give 2-3 question wrong every year .....

Now I think They did Intentionally To Earn Some money ...

You think Atleast 100 (I know It will be more and more But asuume Minimum posssible) People will atleast Challange to One question out of 13,00,000 Student's ...

So This gives Total of 1,00,000 Rupees ... And All their " KARCH A " of Conducting Exam is Paid off...

So They are really Bullshitt *

Am I right @Ronak Agarwal @Mvs Saketh @Raghav Vaidyanathan @Karan Siwach Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat What about the 135 crores they make from the entrance fee for JEE-main? Krishna Ar · 2 years, 1 month ago

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@Ronak Agarwal That's the answer to every question on this post. Karan Siwach · 2 years, 1 month ago

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@Ronak Agarwal Bravo! Raghav Vaidyanathan · 2 years, 1 month ago

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CBSE is foolish .

NCERT freaks they must accept what is true not what NCERT says.

They must learn from IITs how they conduct Jee Advanced. Ronak Agarwal · 2 years, 1 month ago

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CBSE people are $%^t to the core. Last year, AIPMT had 6-8 errors in biology (Even according to NCERT, multiple options were correct, CBSE gave marks to only its choice). The entrance exams must be controlled directly by the Government of India /HRD or worst case, NCERT. At least, the NCERT fellas are more knowledgeable than foolish CBSE h%les Krishna Ar · 2 years, 1 month ago

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And what about the two Mathematics Questions -
1.The differential equation question
2. and the ball and the boxes question Both of them are ambiguous too... Bhartesh Mishra · 2 years, 1 month ago

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@Bhartesh Mishra What's the problem with the differential equation one? it was correct. Krishna Sharma · 2 years, 1 month ago

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@Azhaghu Roopesh M ; now please tell marks you are getting according to the official answer key. Karan Siwach · 2 years, 1 month ago

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How much did everyone get officially? Mohan Nandakumar · 2 years, 1 month ago

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@Mohan Nandakumar you..?? Mahimn Bhatt · 2 years, 1 month ago

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@Mahimn Bhatt 315.What about you?? Mohan Nandakumar · 2 years, 1 month ago

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@Mohan Nandakumar OMG.....!! Pranam guruji...i would have told you but i a getting very less Mahimn Bhatt · 2 years, 1 month ago

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@Mahimn Bhatt Please man, don't call me guruji,I guess I was just lucky.Anyway,the real competition is JEE advanced. Mohan Nandakumar · 2 years, 1 month ago

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one question regarding force on solenoid ,the answer key gives the wrong answer the answer must be both forces are 0(zero). Nikhil Tanwar · 2 years, 1 month ago

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CBSE shits this year. Time taking maths board paper, then a time taking problem in mains which was wrong after finding it in news. Really, if I have not spent more time on that wrong one, I could have gained 8 marks or 2 question. That means if the avg of iit scores is somewhere around 150 (assumption only), loss of 8 marks means 142, or drop of nearly 10000 ranks. So it can be an intentional error, or just a coincidence that printing machines were making fun during the mains paper print :) Suvendu Barik · 2 years, 1 month ago

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Everyone please help me with the following question, it was in online paper 11th april..... Also if it is correct should i CHALLENGE OR NOT????

https://drive.google.com/file/d/0B_Z4jeq8U2z4NTU0ZmFxQjBuYlE/view?usp=sharing Mahimn Bhatt · 2 years, 1 month ago

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@Mahimn Bhatt What is your doubt in the problem? Option 1 seems to be right @Mahimn Bhatt Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan @Raghav Vaidyanathan - Answer key tells that answer is Option 3. Mahimn Bhatt · 2 years, 1 month ago

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@Mahimn Bhatt SORRY to annoy you guys..........@Karan Siwach @Karan Shekhawat @Ronak Agarwal @Krishna Sharma @Raghav Vaidyanathan Mahimn Bhatt · 2 years, 1 month ago

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Everyone please help me with the following question, it was in online paper 11th april..... Also if it is correct should i CHALLENGE OR NOT???? https://drive.google.com/file/d/0B_Z4jeq8U2z4NTU0ZmFxQjBuYlE/view?usp=sharing Mahimn Bhatt · 2 years, 1 month ago

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They are not giving marks for the wrong probability question. Ayush Gupta · 2 years, 1 month ago

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@Ayush Gupta Actually, they are stupid people. Karan Siwach · 2 years, 1 month ago

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@Karan Siwach Yes,you are right.They are stupid. I wasted a lot of time on that question. And finally did not attempted it. Ayush Gupta · 2 years, 1 month ago

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@Ayush Gupta exactly, that too, all, fiitjee, resonance, even VMC and pathfinder have marked it wrong Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh But that question is right.. I'm not saying this blindly(I got it wrong too). Probability is a touchy topic. It's second to none but limits. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan I am in favour of you Raghav, my friend very wonderfully explained me this :

He said it depends on how you distribute the balls for example if we are distributing balls one by one into the three identical boxes then the distribution 3-3-6 is much favourable than 12-0-0. In this case CBSE is 100% correct.

And if you distribute like say you have 20 possible distribution and you randomly select one distribution then one would use probability by outcomes. Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal do you mean in the sense that, if i distribute it ball wise, then you have 3 choices for each ball even though they are not distinct and so correct, but if you perform all distributions and then pick one randomnly out of all, then it becomes the no.of outcomes/ total and hence wrong,

But, isnt this still ambigious? Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh The balls are distributed in such a way that each ball has equal probability to be in one of the three boxes. Raghav Vaidyanathan · 2 years, 1 month ago

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@Ronak Agarwal Correct. I tried explaining the same in my note which I had posted to discuss about this problem and the common misconceptions that lead to its dispute. @Mvs Saketh keeps claiming that according to the classical definition of probability, it is wrong. Although he is partly right, I think that the classical definition favourable cases divided by total cases is valid only when all the cases are equally probable, but in the relevant problem, they are not. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan i get you now, if i distribute box wise, then surely i have 3 choices per ball, but i simply list all possible observations , then the fact that i will find many observations similar means that i will say probability is less,

and may be it is correct to say that the most logical alternative is distributing ball wise, because we are performing the experiment and not simply observing all possible outcomes.

so i suppose it is correct, more or less Mvs Saketh · 2 years, 1 month ago

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@Raghav Vaidyanathan I thought it was wrong, right? You wouldn't get the answer even if you assumed that the boxes/balls were distinct. Siddhartha Srivastava · 2 years, 1 month ago

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@Raghav Vaidyanathan no, i do not blame you, but the point is that when it comes to math, it becomes a matter of precise definition

The classical definition = no. of favourable outcomes/ total number of outcomes

i agree to your point that you made in your note, but bro you know, in statistical mechanics, the entropy is different for distinguishable and non distinguishable particles and hence the number of outcomes and sample space

(example, entropy change doesnt occur if two identical containers of nitrogen diffuse into each other but does when they are different isotopes or gases) Mvs Saketh · 2 years, 1 month ago

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Also I can't get why isn't anyone debating the problem based on Hall-Herout process it asked for False statement but all the statements are true. Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal Exactly, according to JD Lee, in reference to Hall-Heroult process "A typical electrolyte mixture consists of 85% cryolite". It's on page no.362. I hope CBSE gives a bonus. Sheshansh Agrawal · 2 years, 1 month ago

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@Sheshansh Agrawal Hi Genius sheshansh...! How much are you getting ... I blieve It must be 310++

Please Reply

And Yes They should... But For this one has to report to that question ....

Btw Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat Does anyone know's who is the topper of Jaipur ?

My frriend Tells that ALLEN has Scored 336 .... Is this you @Sheshansh Agrawal Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat I got 335, my friend has got 341 with the CBSE key. He was at 336 by ALLEN's answer key. Sheshansh Agrawal · 2 years, 1 month ago

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@Sheshansh Agrawal Who's getting 341 can you please tell me. Ronak Agarwal · 2 years, 1 month ago

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@Sheshansh Agrawal That's Great Score ... Btw who is that person " 341 " ? I think It will be Highest in our state...

Since Last Year 345 is highest from state ...

@Sheshansh Agrawal Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat There's no doubt about it I suppose.

@Karan She Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal Same here Ronak ..... I unnecceserrliy Got that question wrong ....

Btw what is TUKA to that Question ? Why Cryolite don't serve as Electrolyte ?

When I read Resonance Answer ... I reallly Laughed ....

@Ronak Agarwal Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat Resonance is foolish.Fiitjee is foolish everyone who didn't gave hall-herout one as bonus is foolish. Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal Yes... It really Heart's ..

Btw as of now What is your current total ? Karan Shekhawat · 2 years, 1 month ago

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@Karan Shekhawat yes resonance answer is particularly stupid, "although it is an electrolyte , it serves as solvent" "why?- because some option must be right" Mvs Saketh · 2 years, 1 month ago

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@Ronak Agarwal Actually, I had a problem with that question too. But wikipedia is in favour of CBSE. :( Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan @Raghav Vaidyanathan - it is written in CBSE that it is also used for enhancing conductivity, and anything that enhances conductivity is usually an electrolyte (especially when its a salt with sodium in it) Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh Yes, I do agree with you. But theoretically, Hall-Heroult process could be carried out in the absence of cryolite also. It's primary function is to reduce the melting point of the mixture. Hence, the most appropriate answer would be that one. Again, I'm not speaking blindly, I got this one wrong too. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan Please get your definitions clear understand the fact that electrolyte is a substance that ionizes in a solvent and obtains capacity of conductivity.

Na3AlF6 functions as an electrolyte. 100 % Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal I'm not saying that you are wrong. Just that you are less right. Most appropriate. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan yes, it is surely the most appropriate one, that is why i didnt debate about it , Mvs Saketh · 2 years, 1 month ago

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The solenoid one I want both the answers to be given because it was not clearly asking how they exactly require force( that is net force or type of force whether radially outward or not )

You see I was sitting 2 minutes blank about that problem thinking what to do.

And finally did the radially outward one.

It is worhty to note that although the net force is zero but still the inner solenoid has a tendency to expand.

I know this comment will create outrage and everyone will tell me they were asking for vector But please understand my feeling I was confused because of the options.

Hence I am in favour of giving both answers. Ronak Agarwal · 2 years, 1 month ago

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@Ronak Agarwal that depends on what they want, but they should specify whether they want the nature of force lines or the resultant force

I did think about the hall heroult one, but i thought perhaps there is some detail about it which i missed so didnt say anything Mvs Saketh · 2 years, 1 month ago

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@*#$!, now I get why everyone was swearing. I lost \(14\) marks from expected score, assuming they don't give bonus marks for the question they cancelled. Didn't even cross \(290\). Those @$$#0!($. Here are the questions that I think are given wrongly in key:

  1. The ion-dipole/ hydrogen bonding question. (intermolecular attraction that is dependent on inverse cube of distance).

  2. Force between two coaxial solenoids.

What I feel is that they won't change the key. Those self righteous nice people will not have their ego hurt. And it's hard to say this, but they might even turn out to be right. Hoping that they give bonus, so that I can atleast cross \(290\). I'm sure you guys are thinking the same @Shashwat Shukla @Mvs Saketh Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan The are really $$@#%! Karan Siwach · 2 years, 1 month ago

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@Raghav Vaidyanathan yes, my final score stands at 284 , unless CBSE rethinks, hope it does, some one will report it surely, atleast those at the border of cutoff will, hope they hear Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh I'm sitting at 289. My father says that they have no choice but to give grace marks for the deleted problem. If they do not do that and decrease total instead, then it will be an unfair advantage to the people who wrote online. So, I'm hoping for the best. As for the disputes, I think it is just a good way for CBSE to earn money. I would rather bet 1000 bucks that they won't change a thing rather than spending it trying to correct them. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan yes, i appreciate their cruel innovativeness regarding that( money making), but then, it is not easy handling disputes from such a large body of students crossing several 10s of thousands, they should have been more careful while making the answers instead.

I mean, may be it is true that hydrogen bonding varies as inverse cube , perhaps its a fact we do not know, but then they should make options accordingly as well, because they must realise that we can easily derive that ion-dipole interaction is an inverse cube law,

but remember that last year one question was awarded free marks and hence perhaps they will this time as well (atleast for the solenoid one) Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh Nope, I don't think they will change solenoid one. As for the ion dipole problem, it has been mentioned in the class 11 ncert text that hydrogen bonding follows the said inverse cube law. (check gaseous state). The problem is that they have not mentioned anything about ion-dipole forces. Even in wikipedia, no explicit dependence of ion-dipole forces on distance has been mentioned. All that has been said is that ion-dipole forces are stronger than hydrogen bonding(which doesn't mean anything w.r.t current discussion).

But there is a small problem, we have derived the ion-dipole formula based on a number of assumptions. The first is that the ion-dipole system behaves as a permanently charged entity, i.e as discrete charges and not stuff like misshaped electron clouds. This assumption seems to be true, according to wikipedia.

The second assuption is that the ion and the dipole are very far away. This is what I'm not sure of. Yes, the charges can be considered as point charges w.r.t the distances involved, but can the distance between the charges of the dipole be neglected w.r.t the distance between the dipole and the ion???

As I said, not worth spending money on. 1000 bucks is more than enough for a good dinner for all of my family. Raghav Vaidyanathan · 2 years, 1 month ago

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@Raghav Vaidyanathan bro, when you think about it, even hydrogen bonding is simply a weaker form of dipole-dipole or ion-dipole (based on the constituents involved) interaction, and no formula be it physics or chemistry (ultimately you must depend on physics only ) at the atomic level where nothing is perfect (partly ionic nature) can be derived without assumptions.

It should be mentioned at the heading that "THOU SHALL NOT USE LOGIC IN THIS QUESTION"

and yes, let it be, let us prepare for advanced , !@#$ this shit, not worth a grand Mvs Saketh · 2 years, 1 month ago

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@Raghav Vaidyanathan @Raghav Vaidyanathan , class 11 NCERT says "energy" in dipole-dipole interactions and hence, hydrogen bonds varies as inverse cube which means force varies as inverse fourth power. It was also expected from the physics. So, CBSE is wrong even according to NCERT. Sheshansh Agrawal · 2 years, 1 month ago

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Hey, almost all sums were OK I say. Jee mains didn't make us cry that much. Well, that cryolite sum was bit ambiguous, as cryolite is just the ingredient in hall process. That probability sum was fine, but time taking because of judgement of better method to solve it. I cried for the differential equation sum, as it was also easy, but no answer. Then many physics sums were direct from the ncert example. So overall, the paper was a cakewalk for those who referred fundamental materials for the preparation. Suvendu Barik · 2 years, 1 month ago

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@Suvendu Barik it was cake walk, no one has a problem with paper, we have problem with answers Mvs Saketh · 2 years, 1 month ago

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@Mvs Saketh Anyhow. It was OK. You had problems in answers. Majority lost time by solving wrong ones. So both are the two sides of coin here. Suvendu Barik · 2 years, 1 month ago

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@Mvs Saketh That's the problem. Who knows CBSE has corrected themselves? As questions were great, CBSE makes more blunder in it. 105 was cutoff for General category. Why so low? That shows that some normalisation took place. Suvendu Barik · 2 years, 1 month ago

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@Mvs Saketh hehe yes Mahimn Bhatt · 2 years, 1 month ago

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