hey, help in this one
https://brilliant.org/problems/getting-back-to-the-old-things-6/?ref_id=1368848
thanks in advance.
give me some hints as usual(Which i ask from u from 11th :P)

Use the concept of deviation caused by a convex lens. A ray of light reaching the lens at a distance 'y' from the optical axis suffers a deviation of delta=y/f . Now, the lenses are seperated by distance l by which you know the rate of change of slope which is delta/l. Set up the differential equation and you would get the result. @Richeek Das

@Md Zuhair
–
Why bro? Overall how was your JEE ? This time the paper was easy thats what I got to know. But still there are some mixed reviews. Anyways you have another chance on April & all the best for Boards bro!

@Md Zuhair
–
I guess your rank will be around 1600-4200 :''''''''''( ......Its okay, you have another chance bro to get a better rank in mains! And study harder for the one in April. Trust in yourself and stay motivated :)

@Md Zuhair
–
Who said you have no chance? You have chance toh! The one in April is is your hand, kill it there! And honestly 200+ isn't okay, it's really good bro.

@Nashita Rahman
–
I know far far far better people than me landing up at 230 s .... I mean... They had AIR 156 in KVPY SX. They were really awesome.... So I am not that sad too... still... lets see.... Well JEEA is the real game.

@Aaron Jerry Ninan
–
I have solved this one , but I would really like to hear the way you had solved it !
https://brilliant.org/problems/when-einstein-meets-huygens/

@Richeek Das
–
My Percentile is not as good as urs. But approx 99.6 :(((((. Well help me in this plz
Anyone
https://brilliant.org/problems/getting-back-to-the-old-things-6/?ref_id=1368848

@Md Zuhair
–
-------__------ Your one is also great!! Do you want me to write a paragraph explaining how good your percentile is ? :P Anyways, move on with it and focus on what's coming next!

@Md Zuhair
–
Richeek has definitely done very well, no doubt about that. I can't even dare to insult him! I am so proud of you Richeek :P But @Md Zuhair you also did well and I am proud of you as well :P

If I get 99.6 percentile in JEE Main January and again 99.6 percentile in JEE Main April, then due to different number of students appearing in two shifts,My AIR will be different,How will NTA then normalize this?Will they combine AIR of both or the NTA score ?Wouldnt it be unfair if they combine NTA score(for merit list) as the total students appearing will be different.

@Md Zuhair
–
The total number of students appearing for JEE Mains 2019 will be the maximum of the number of students appeared on Jan and appearing on April. So your AIR won't be different as the total no.of students is the maximum appearing from the two shifts. Basically if 3 lacs appeared in Jan and 3.1 will appear in April, your rank will be out of 3.1 lac students and not 3 lacs. That is the reason they haven't revealed the rank after JEE mains Jan and so have decided to release the rank after JEE mains April. They won't combine your rank or anything from the two shifts. This is what I can guess with logic as of now :P

@Md Zuhair
–
Your best percentile will be taken from the two shifts. AIR will depend on the number of students appearing for JEE Mains April, you have time so it's in your hand :P

@Nashita Rahman
–
If this is really the case then, this is the worst system ever devised for an examination of this scale. Are they treating it as a joke or what :O
BTW, I won't even appear for April JEE Main :P

@Richeek Das
–
It seems nonsensical... I mean... two JEEM system is okay... But this percentile normalization is bogus! I mean they set our percentile as per JEE Mains Jan version and then they use it for JEE Mains April(Where no. of studs are diff..), Now we are ahead of certain amount of students which gives us our percentile. What is the guarantee that our percentile wont increase if more students gave? It might be that the extra students who are giving are not giving JEE seriosuly!! Isnt it?

@Richeek Das
–
Obviously.... dukkho nahole he is a robot not a human being. Jemon ami ei bochor KVPY miss korlam by 0.5 marks :(... Just a very sad ... very sad life... Amar AIM oitai chilo.. ki crack KVPY ... to gain some confidence .. karon i have 0 self confidence...

@Md Zuhair
–
Woahhhhh! Congratulations !!!!!!!!!!!!!!!! I didn't see the newspaper today but will see it right now. It's your day today:P Proud of you!!!!!!!!!!!!!!!!!!!!!!!

@Nashita Rahman
–
Now dont make fun of me :P. I really couldnt do good in JEEM 2019 like my friends who use to score similar marks in All India test series.... Still i am thankful to god for what i got :) ...

@Md Zuhair
–
I am not making fun of you -_- How can I make fun of such a talented person? And why are you comparing yourself with your friends? I still remember how you were once giving me advice on not comparing xD

Quora misses you bro ;) How's your studies going? Also, tell me how are you motivating yourself everyday? And not to forget only one day left for this year to end LoL xD

@Md Zuhair You used Quora from another account LOL xD There was no point in deactivating your own account then LOL ... This is so funny! Also, do you really know Prakhar Bindal? You yourself answered that question, right? The writing pattern was similar to yours. And study hard for Boards, All the best!

@Nashita Rahman
–
Haha... I opened it after JEE na... so it had point.. As i used to read how others gave the exam and what answer keys were faulty by NTA. After that i deleted it a few days ago i guess.. I deleted the account. And Yes... I know prakhar bindal persoanlly... and i didnt knew i was so famous :P..... Well.... Akhon abar shob deleted... Chap nei... chere diyechi oi shob :P...

@Nashita Rahman
–
Where am i famous? Rastai nijer family member e chinte pare na... They avoid me i guess...(Bhabe... er kache gele amar cheleo fail o korbe..:PP. )

Well... i took decision of deleting it again as i had the similar experience as i had with the previous one. So i deleted this also. I guess will open after JEE agian.

@Md Zuhair
–
Eto bhaat keno -- nijer family o Cheney na seriously STOP --
It's okay open it whenever you want to, no one will force you it's your life , you have the freedom to do whatever you want to LOL

@Md Zuhair
–
First duto line seriously hojom hochchena -__- Heights of sarcasm xD
I will be too deleting my account soon, will be back on July because I have my finals on June. Till then you'll be super famous, your name again on the newspaper :P Ar koto famous keu hote pare :P

@Swapnil Das
–
LOL define the domain of everyone!! Btw how was the physics paper? I got some mail from you regarding the physics paper. Good to see you back on Brilliant after a long time. Also do you know that Brilliant has deleted it's Slack Team?

@Swapnil Das
–
This really happens almost every year. Some people create more mess and chaos regarding this. Conclusion : No one trusts the education system of our country, sad reality. No one knows who to be blamed for the paper going bad, students for not studying or CBSE for making an unusual paper.

@Richeek Das
–
Arre... Then I know you. I have a friend named Rishav Dugar. He said the you are the smaller version of Arka Das. So I know you that you are a topper!!!

@Richeek Das
–
I tried it this way. Taking the lens to be thin. I found the number of lens it will overcome until it reaches 3.925cm . Now taking the equivalent of all those lenes we ge the point where the ray would have passed if there were no further lens cutting the principal axis (focal pt) . Ebar....Using perpendicular/base.... =Tan theta(theta is angle b/w ray and principal axis). We can find out the height. If I am wrong somewhere.... Plz correct me. My answer is not matching.

@Richeek Das@Md Zuhair bro could/can you solve this ? https://brilliant.org/problems/tetrahedron-impedance-planar-network-what-is-the-2/. If so, are you using the standard approach to solve this? Or there's any trick?

@Md Zuhair
–
Please don't start crying :P I know it's sad but what can you do now? Just mail the brilliant staff regarding this as simple as that !! And how are you? All is well? XD

@Nashita Rahman
–
Thats my fav. film. After that, I got Inspiration to do Engineering as i found machines impressive and interesting. And that inspiration is working now also... Lets see where this inspiration ends me up

@Md Zuhair
–
Yeah I know that it's you fav film :P (You've mentioned it somewhere) .... That's really awesome. Inspiration always leads to something great, I am sure you'll end up doing something great.

@Nashita Rahman
–
No no no no !!!!!!!!!!!!!!!!!!!!!! HE has not left brilliant ! Man!

What he replied :
"Hi,

I am out of the office. For YouTube and sponsorship matters, please email Tara Kappel at tara@brilliant.org. For anything else, please email eli@brilliant.org and cc me.

Thanks."

I am extremely sorry!!! I really don't know why I said that "he has left Brilliant". I really really don't know !!!! Seems like I was high.

@Richeek Das
–
Topper like you go high after getting into IIT. One of our sir from Aakash is from IITKGP Mechanical. And he said.... CS waalo sab se zyada high rehta hai.... As they have really tough assignments and tough work... So they go high for some time

@Richeek Das
–
I MUST SAY THAT YOU BELONG TO JUPITER! People or rather aliens from Jupiter go high like this. Happy journey and stay on EARTH.

Jokes Apart, you should be sorry -_- . Calvin sir is one of the most important part of Brilliant, he can never ever leave brilliant. I am here on brilliant since six years though not really an active member but I have seen tremendous contributions of Calvin sir to Brilliant.

Hey.... We know that at freezing point.... The liquid is in equilibrium with the freezed solid. How can we calculate how much water has freezed?(Random qs.... It just came to my mind..... Idk :P)>> is it the same way we do for others... Like we need alpha and K?

In case of pure water, the whole of it will convert into ice at its freezing point. If there is any impurity in the water then the amount that has freezed can be calculated using Kf provided del Tf ( which says whether the freezing point has decreased/increased) is given. I hope it is clear?

@Md Zuhair
–
At freezing point, water starts to freeze then the temp will change only when whole water is converted to ice. Water freezes at the same rate as ice melts that's why there's a dynamic equilibrium . In my previous comment, I wrote that whole of it will convert into ice at freezing point was a mistake, sorry.

@Md Zuhair Yes I am from CBSE board, the marking is alright but getting above 95 isn't easy at all!!! If you've solved the ten years questions then you must be knowing the question pattern . I can't say whether you'll get more or less than your expected marks because it depends on many factors like who will check your paper, a strict/lenient teacher and all other factors. Just study hard and give your best!

@Nashita Rahman
–
-_-... Anyways... I guess I can apply for IISc as per last year's cutoff. But I won't be applying as I don't want to study basic science anymore after missing KVPY by just 2 marks :(

@Md Zuhair
–
You missed KVPY by two marks :"""( That's sad, but it's okay, you still have other good opportunities in hand . Rock it in JEE Advanced xD What will you pursue? Engineering?

@Md Zuhair
–
Why are you loling -_-
Hint : Use POAC for [PO4 3-] (initial) and overall and find the phosphate ion concentration roaming around in the solution...

PO4 3- + H2O ---> HPO4 2- + OH-
.
.
.
I guess you know that approach.

@Richeek Das
–
LOL why didn't you care about JEE ? Do you have any other career plan ? Also, trust me AIR 497 is an amazingly amazing rank, you should definitely be proud of yourself, it's an achievement. Once again, congrats!! All the best for JEE ADVANCED!

@Richeek Das
–
Ok.. but most of the cases.. I see KVPY SX toppers or even qualifiers go for IIT .. and you will get to learn physics in ECE or EE.. so you can take that up.. because thats based upon physics totally... CSE is kind of something else ..... not what we did for JEE till 12th.. but its something very different

@Md Zuhair
–
Oh... So I've enrolled in "cheenta" they are providing mock interviews ...i know it's quite unnecessary but still I don't want to leave a chance.

@Praveen Kumar
–
Hey lets make a contest of ISI interview with question sharing? Would you like doing it? I will send you a link shortly... with all the rules.. just wait.. :D

@Md Zuhair
–
i believe the interviewer wont ask very tough questions,
they would just check basic understanding of number theory , calculus, pNc,etc
and some problem solving skill.

$</code> ... <code>$</code>...<code>."> Easy Math Editor

`*italics*`

or`_italics_`

italics`**bold**`

or`__bold__`

boldNote: you must add a full line of space before and after lists for them to show up correctlyparagraph 1

paragraph 2

`[example link](https://brilliant.org)`

`> This is a quote`

Remember to wrap math in $</span> ... <span>$ or $</span> ... <span>$ to ensure proper formatting.`2 \times 3`

`2^{34}`

`a_{i-1}`

`\frac{2}{3}`

`\sqrt{2}`

`\sum_{i=1}^3`

`\sin \theta`

`\boxed{123}`

## Comments

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TopNewestWhat did actually happen to saved sets??

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Unfortunately, brilliant has removed them. I don't know whether this feature will come back . For further enquiries, you can mail the Brilliant staff.

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That was the best feature of brilliant :(

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There is now an option named as "Saved" below the notification panel. I hope you'll find your saved sets there. Check it out!

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@Md Zuhair

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+2348103182839...Please add me to the group.. I will be very happy

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@Md Zuhair @Rahil Sehgal @Ankit Kumar Jain - I also want to join. Please add me.

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Pls comment your contact number below so that I can add u. :)

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hey, help in this one https://brilliant.org/problems/getting-back-to-the-old-things-6/?ref_id=1368848 thanks in advance. give me some hints as usual(Which i ask from u from 11th :P)

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@Rahil Sehgal what all will you discuss in the group

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Please comment if you got it.

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Thanks...

I have added you in the group

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Thanks.

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https://brilliant.org/problems/too-many-lenses/?ref_id=1559097

Can you help me with this problem ? You don't need to provide a solution, a hint will work for me.

Thanks in advance.

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Use the concept of deviation caused by a convex lens. A ray of light reaching the lens at a distance 'y' from the optical axis suffers a deviation of delta=y/f . Now, the lenses are seperated by distance l by which you know the rate of change of slope which is delta/l. Set up the differential equation and you would get the result. @Richeek Das

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Are you in FIITJEE too?

Thanks again!

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I could have got 260. But very silly mistakes brought me down here. Never mind :(.

Still...

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Can you clarify?

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@Md Zuhair I spoiled it by lots of silly mistakes + stupid calculations (even (sinx)^2+(cosx)^2+1=3) .....expecting border 300.

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@Md Zuhair @Aaron Jerry Ninan

What is your final percentile ?I'm getting around - 99.9633219 percentile ! I was pretty shocked :( I had expected much better as my marks was 319 .

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@Md Zuhair @Richeek Das

Wowww :P Congratulations!Log in to reply

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__------ Your one is also great!! Do you want me to write a paragraph explaining how good your percentile is ? :P Anyways, move on with it and focus on what's coming next!Log in to reply

He is legendary :P

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@Md Zuhair you also did well and I am proud of you as well :P

Richeek has definitely done very well, no doubt about that. I can't even dare to insult him! I am so proud of you Richeek :P ButLog in to reply

XD

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If I get 99.6 percentile in JEE Main January and again 99.6 percentile in JEE Main April, then due to different number of students appearing in two shifts,My AIR will be different,How will NTA then normalize this?Will they combine AIR of both or the NTA score ?Wouldnt it be unfair if they combine NTA score(for merit list) as the total students appearing will be different.

@Richeek Das @Aaron Jerry Ninan @Thomas Jacob @Ankit Kumar Jain .... HELP! :p

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--------__Log in to reply

Such talented people! Much wowww :O btw you all are just increasing my notifications lol!!

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Newspaper e naam beriyeche. Telegraph page 5. Also in anada bazaar. but percentile given there is bit incorrect (:((()

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@Md Zuhair Bro :''''''''''"""'"""""""""((((((((

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@Md Zuhair Bro see what I found https://epaper.telegraphindia.com/calcutta/2019-01-25/71/Page-5.html

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@Md Zuhair Bro yyyyyyyyyyyyyyyy^(infinity) didn't you reply? -----

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@Md Zuhair @Rahil Sehgal - Can you please add me to the group too?

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You can comment your contact number below. Thanks.

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Would you please add me too ,my number is 8547853228

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What kind of group is it ? Formal one for physics and math problems ?

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Kind of.....

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Ohh okay!

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Quora misses you bro ;) How's your studies going? Also, tell me how are you motivating yourself everyday? And not to forget only one day left for this year to end LoL xD

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Happy New Year!

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@Md Zuhair You used Quora from another account LOL xD There was no point in deactivating your own account then LOL ... This is so funny! Also, do you really know Prakhar Bindal? You yourself answered that question, right? The writing pattern was similar to yours. And study hard for Boards, All the best!

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Well... i took decision of deleting it again as i had the similar experience as i had with the previous one. So i deleted this also. I guess will open after JEE agian.

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- nijer family o Cheney na seriously STOP -- It's okay open it whenever you want to, no one will force you it's your life , you have the freedom to do whatever you want to LOLLog in to reply

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__- Heights of sarcasm xD I will be too deleting my account soon, will be back on July because I have my finals on June. Till then you'll be super famous, your name again on the newspaper :P Ar koto famous keu hote pare :PLog in to reply

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Btw, @Swapnil Das... How was your JEEM?

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Are you still adding students ? BTW I'm a JEE aspirant and I'm quite new to brilliant(Using it just for 1-1.5 months)

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+919903607651

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no bro... actually i deleted Whatsapp 6-7 month before :P

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Obviously. Friends with toppers like you would be a nice thing Id love to

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What do you mean by "topper" ? -_- Do you even know me ?

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your credentials say all :)

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please help me with this!

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The exact answer is $y = hcos(\frac{x}{\sqrt(lf)})$

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Oh so we need to find out the exact path of ray. I thought approximation would work

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Ya

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I have solved this , but I want to know if there is any better solution than what i have done ! Help me.

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@Richeek Das @Md Zuhair bro could/can you solve this ? https://brilliant.org/problems/tetrahedron-impedance-planar-network-what-is-the-2/. If so, are you using the standard approach to solve this? Or there's any trick?

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@Nashita Rahman No i dont have them even in the 'saved' section. :(

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Ohh NO :( Try mailing the brilliant staff about this, they might help you to get back your sets.

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It seems impossible to get them back i guess :((((.... I had a set with doubts which I had to ask to my teachers.. Its lost!

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What he replied : "Hi,

I am out of the office. For YouTube and sponsorship matters, please email Tara Kappel at tara@brilliant.org. For anything else, please email eli@brilliant.org and cc me.

Thanks."

I am extremely sorry!!! I really don't know why I said that "he has left Brilliant". I really really don't know !!!! Seems like I was high.

I am sorry

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Jokes Apart, you should be sorry -_- . Calvin sir is one of the most important part of Brilliant, he can never ever leave brilliant. I am here on brilliant since six years though not really an active member but I have seen tremendous contributions of Calvin sir to Brilliant.

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Hey.... We know that at freezing point.... The liquid is in equilibrium with the freezed solid. How can we calculate how much water has freezed?(Random qs.... It just came to my mind..... Idk :P)>> is it the same way we do for others... Like we need alpha and K?

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In case of pure water, the whole of it will convert into ice at its freezing point. If there is any impurity in the water then the amount that has freezed can be calculated using Kf provided del Tf ( which says whether the freezing point has decreased/increased) is given. I hope it is clear?

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Who will create the INO 2019 PAGE????

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@Aaron Jerry Ninan How was your INPhO 2019 ? Did you get through ?

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@Md Zuhair Yes I am from CBSE board, the marking is alright but getting above 95 isn't easy at all!!! If you've solved the ten years questions then you must be knowing the question pattern . I can't say whether you'll get more or less than your expected marks because it depends on many factors like who will check your paper, a strict/lenient teacher and all other factors. Just study hard and give your best!

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Ok. But what happened with you? More than expected or less?

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Congratulations!!! @Md Zuhair And all the best for JEE Advanced!!

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for what? -_-

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What else can it be? -----

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@Md Zuhair All the best !

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PO4 3- + H2O ---> HPO4 2- + OH- . . . I guess you know that approach.

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@Richeek Das

Heyy! How did you perform in JEE? What's your AIR?Log in to reply

I didn't appear for April one so i guess that might be the case :(

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P.S : The rank is bad.

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Advanced is my target and KVPY was my target.

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P.S. I have final exams from 3/6/19, I am going offline for 2 months. Hopefully I will survive without internet :"""(

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+I don't know whether I can live with little or no social life in IISc :/

+Literally everyone will force me to join IIT if I manage to get one :/

I will discuss with some IISc students about their lives in there and then I will decide.

P.S - My parents won't force me ever.

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@Md Zuhair I will either go for CSE(if i get it) or IISc(for physics).

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@Md Zuhair Because I like both physics and CS. Mane janina, ki bolte chaichi. Chaar bhai, agey toh Advanced hok XD

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@Richeek Das

Bhai eta try kortoh... tell me if the answer is correct

https://brilliant.org/problems/600000-points-problemfor-jee19/?ref_id=1569043

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Bapre pore korbo

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Hey zuhair, we have isi interview on the same day... 18th June... I wanted to know.... How many subjectives did you solve in the UGB?

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ohkay....i solved 4.5 qs at UGB and got 97/120 in UGA

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how are you preparing for this? Please help

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https://artofproblemsolving.com/community/c260h1847186p12443026

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