JEE ADVANCED 2019 SOLUTIONS - The Best Video About Least Count Error Yet!

[@PHYSICSSIRJEE]

Errata : As some of the viewers pointed out , Actual calculation of error will involve three readings position of object R1 , position of lens R2 and position of image pin R3 . Each of these readings will have LC/2 error and are independent . But u = R2 - R1 , v = R3 - R2 are dependent errors and won't have even LC has error . So final solution will change accordingly when formula for f is written for Readings R3, R2,R1 and then differentiate and solve. Even though I missed this point in the end of the video , I am glad that my viewers caught the essence of what the least count error is and how dependent errors are dealt with in my previous video 🙂👍🏼. 2LC by JEE key is still wrong ----------------------------------------- All the practice problems would have been doubts of top students at some point or other , with no answers to be found until unless they are taught by a Good teacher 🙂 The plan of the video is to also highlight some of the "unexplained" statements in ERROR Analysis topic from NCERT textbook . Enjoy the video👆🏻 and smash the LIKE button to spread the love 💕 for the channel and to get the next video 🙂

[@biswaranjan_4425]

Not sure whether I am a top student or not,but I had a lot of conceptual doubts which my teacher didn't address in jee class (maybe cz of time constraints or maybe they didn't want to clarify it,idk) This lead to a series of event and I started thinking I am bad at physics and why other people don't have such doubts ,there must be some problem with me and I am not good at physics. For example,I always had doubts in electrostatic shielding which was explained by uniqueness and existence theorem (I didn't know about these,had I known there exist proof ,I won't have been confused at all) Or while taking the iaor for a body rolling,is it the space point or the material point ,I used to have doubts but I felt that it's me who isn't learning properly so I thought maybe I wasn't good at physics at all. I used to be a book learner and I used to learn things better way when I used to read something from book along with teacher explaining the concept,but the two years ,I was said that reading books will waste my time and what not. I always wanted to make physical sense of things which I was taught in physics along with intuition,but this process was painfully slow which was accelerated by doing problems tho,but it was worth it.:) WhenI came across your channel and few more channel,I realised none of my doubts were invalid (but I used to think little bit more mathematically and was inclined to read books on physics).. 7-8 of my doubts were cleared in resolved series and I felt confident after that. I found solution to neary all of my conceptual queries from this channel .. When you mentioned some comments were dramatic in video😅I thought u were talking about mine as you showed the comment 😅and for a while I was scared..But then I realised mine wasn't dramatic 😅...(I hope this isn't dramatic 😂) Most of my queries have been addressed in this channel and now I am pretty confident in physics... Thanks a lot sir :) I owe it you ,Nitin sir,Akash sir and Resnick halliday krane :). I am so interested in Physics that I am willing to do pathfinder remaining question after jee advanced :),I like doing it😂 . Have a nice day :)

[@PHYSICSSIRJEE]

@@ayushsarangi4095 I read it 🙂

[@PHYSICSSIRJEE]

@@AtharvaAroraisawesome error in each R1 , R2 , R3 is LC/2 . Please watch the video explanation again

[@AtharvaAroraisawesome]

@@PHYSICSSIRJEE so is it like in the case of a stick the LC/2 error near 0 will come (because we can't say exactly where it starts between 0 and 0.5), but here all we have to do is place the pin at some division and only estimate a reading once so thats why the extra LC/2 is not there?

[@PHYSICSSIRJEE]

@@AtharvaAroraisawesome yes 👍🏼

[@INSP_NITIN]

Very nice and informative video sir jee . 👍👍 JEE paper setters will be at bay after seeing the bashing 😀 hopefully they can make controversy free papers in future . Also if they can release the model solutions .

[@PHYSICSSIRJEE]

Thank you sir 🙂🙏, took me 7 days to finish it . I knew you would like the effort

[@abhisheks5938]

In a way we can conclude that the error/uncertainty in measuring any quantity is not necessarily equal to least count of the measuring device. Least count is the smallest unit the device can measure whereas error/uncertainty is something else. In some cases both may have same value, but many a time uncertainty and least count may not be same. Hence, we need to look least count and error with different lenses, as you did. You assumed error to be e and later found the value of e being L.C/2.

[@obstinatewrecker3156]

the way you bring out statements from the text and ask us to think over makes me feel i m after solving some kind of murder mystery😁 ps: great vid

[@PHYSICSSIRJEE]

Nicely written comment ☺️

[@sankethreddy4455]

That scale example really blowed my mind AMAZING

[@supriya1729]

This is physics that's why we can question over jee paper setters... otherwise if it was chem then they would simply say it's an exception where Newton, Einstein too can do nothing 😁😁😁

[@PHYSICSSIRJEE]

@tushar gupta true 🙂👍🏼

[@supriya1729]

Itna serious baat to mere papa bhi nahi karte -_- 😑 Btw I agree too your words Tushar Bhaiya...☺️

[@seema6498]

16:55 4% 17:50 B, C 18:30 Option A (A is more close to true value thus more accurate, B has more precision in measurements than A ) 19:04 21:40 Least count can be regarded as "random error" upto its small values like 0.001 units in which we can repeat and ascertain the error. But when LC becomes larger in value like 0.1 units even on repeating measurements we'll get the same outcome that is in one direction thus in this case it is referred as "Systematic error" I read about systematic and random error from John R. Taylor. And got concepts cleared through really good examples there. Thank you for the reference to the book. 🙏🙂

[@ishitagoyal18]

2023 aspirant?

[@ashwin2263]

Sir jee everytime you come up with something interesting

[@PHYSICSSIRJEE]

Not just interesting but unanswered questions too 👍🏼🙂

[@ashwin2263]

@@PHYSICSSIRJEE yes sir🤗

[@soniatiwari9986]

@@PHYSICSSIRJEE sir where is the book link

[@aaryansahu2003]

Again a masterpiece with so much analysis!!Thanks sirjee

[@dhruv1712]

Sir ,Please make a video on the Jee 2014 searle experiment question you gave in this video before Jee 2021.

[@sanidhyas3s]

But we simply take the max. possible error equal to LC (in single reading experiments) in almost all other JEE previous year questions as well as elsewhere, shouldn't this rule/concept come up there as well? Like for example while using a meter scale with 1mm least count we directly take our reading as L+- 1mm, are we unknowingly also considering the error at the zero end as well or there is something that separates this from that. Obviously except the cases where they give it out themselves as 10+-0.5 ut in the question itself. Not questioning what you said but just trying to clarify my thoughts.

[@vedantkokate971]

yes sir please clarify this doubt of his

[@PHYSICSSIRJEE]

@Ghzo Ghzon 👍🏼 this should explain above doubt

[@DrakonNyx]

@@PHYSICSSIRJEE I know its too old of a video to comment on but sir the person you replied to seems to have deleted his comment so if you could kindly help with the original doubt i would be grateful

[@ishaanshekhawat4178]

19:09 -is this thing ready atleast pls tell me which one is correct, 66.7+2/+1.8..

[@rushikesh_nale07]

Epic Explaination!🤩👌🙌

[@HOPE-kw9ej]

Sir can u make video of 17:40 before jee advance plzz

[@jeeenthusiast]

Sir at 6:10, lets say that R1 pin is at 0, then the error is zero will be just +LC/2 right sir?(As there is no graduation of scale in left, we are sure that there isn't any negative error) Then to find R2-R1 in this case, how can we maximise it sir? What will be the final error in R2-R1? Pls answer this sir.

[@PHYSICSSIRJEE]

R1 is at 0 doesn't mean exactly at 0 . We can't be certain. Similar to every other reading, even here error is LC/2. So total ERROR in R2 - R1 is still LC

[@jeeenthusiast]

@@PHYSICSSIRJEE thank you sir for ur reply🙏🏻

[@shauryagupta3990]

17:56 ABD?

[@_shwettt]

Amazing explanation sir really needed video on this topic 🤩🤩🤩👍🏻🙏🏻🙏🏻🙏🏻🥳

[@prakharchauhan4538]

Thank you sir for this solution

[@mastermindiniit]

17:38 Official answer is 4... not 8

[@Rishabh-se5yo]

Really !love it sirji🙂♥️

[@pranayp10]

18:59 option a. My explaination would be as it's a second pendulum, time period should be 2s...Also, as the readings, 2.56,55,57 I infer them to precise.

[@Jeeadv-bv5lm]

Sir 2014 jee relative motion problem. Although it’s easy problem, jee gave two answers of which one is wrong.

[@keshavmishra5959]

Don't go into pyq now...as ur jee is after 1 yr...otherwise u will be looking for a source to practise JEE adv type ques @the end...it's appreciated that u are going thro jee problems...but mind that JEE problems will be of best use when u will do them as real test ques and when u are sufficient enough to give full length test..

[@SachinKumar-cd1sg]

Sir please upload solutions of jee advanced 2018 error paragraph question

[@umxng]

Usapho give such great solutions

[@shauryagupta3990]

sir in 16:58 error in change is lenght is taken as 1*LC because of the word exactly which concludes that the first reading is w/o error but in 2019 question the word exact is not mentioned therefore 2*LC is taken .SIR IS THIS REASONING CORRECT

[@arijitpal1364]

19:00 opt A

[@navneetyadav8481]

Sir please make a list of pathfinder question which is relevant for jee to practice in all chapters

[@PHYSICSSIRJEE]

I will try

[@navneetyadav8481]

@@PHYSICSSIRJEE thank you so much❤❤❤

[@ashwin2263]

@@navneetyadav8481firstly start with objectives

[@sankethreddy4455]

17:39 4 percent and advance gave 4 percent only 18:06 ABC 18:36 A Practice problem 1,4,5 are my doubts also sir eagerly waiting for it

[@kinjalsao1146]

18:06 why A?!

[@atharvagarwal6412]

17:39 Why 4? elongation will be calculated by subtracting two independent readings of the wire's length, whose errors should add up. So error in elongation becomes 2*LC giving 8 as answer.

[@naninani4564]

Sir,Generally we take error in measured value +/- L.C. that mean if the value is reported 16 by using instrument with L.C 1 ,it is reported as 16+/- 1.yes i understood how you said it is 16+/- 0.5 but does't it clash every jee problem(taking LC/2 as random error)??

[@saivardhan3511]

Thank you very much Sir

[@fortright6124]

Sir take explanation of 2016 advance paper 1 error analysis que and paper 2 optics and paragraph roation problem

[@PHYSICSSIRJEE]

Sure 🙂

[@shubhayanpan6889]

Thank u sir. Really beneficial

[@deshbhakt8416]

Sir you are just best 🙏

[@yatharthgupta6468]

Sir please make a solution videos of the problem you have given last ..the important ones...because jee advanced coming...this topic is important

[@jsingh190]

Thank u sir U know Physics and does not prove ans as other KZbinrs do to prove only ans without applying concept of Physics

[@fortright6124]

Sir in this type case what we can do our 3 marks will be gone in simple question...😭

[@hardikjuneja1987]

13:44 lol harshit i cant stop laughing , dramebaaz lol

[@triggeredskeletonbankey8864]

Sir I'm already subscribed and I'm always support u sirr....💯...sir plz make a playlist for jee advanced icant find that in aplay list some theory involve playlist🙏🙏

[@PHYSICSSIRJEE]

Entire channel is for JEE advanced except extra syllabus topics

[@triggeredskeletonbankey8864]

@@PHYSICSSIRJEE ok sir

[@naninani4564]

18:23 answerABC like if correct

[@fortright6124]

Cochin institute giving explanation that 2 error were calculate 1 when distance obejct and lense and 2 distance from frrom focus to object so that's why 2LC is this explanation right?

[@PHYSICSSIRJEE]

This means that you have missed the point of above video

[@sanidhyas3s]

@@PHYSICSSIRJEE But we simply take the max. possible error equal to LC (in single reading experiments) in almost all other JEE previous year questions as well as elsewhere, shouldn't this rule/concept come up there as well? Like for example while using a meter scale with 1mm least count we directly take our reading as L+- 1mm, are we unknowingly also considering the error at the zero end as well or there is something that separates this from that. Obviously except the cases where they give it out themselves as 10+-0.5 ut in the question itself. Not questioning what you said but just trying to clarify my thoughts.

[@PHYSICSSIRJEE]

@@sanidhyas3s Max error in complete length measurement is LC . It involves two readings and not one

[@pranayp10]

Sir, I had a constructive recommendation. Why don't you and your peers in teaching collaboratively give proposal to the IIT ADVANCED COMMITTEE to provide solutions to ADVANCED PROBLEMS from this year along with options.

[@xrxr2463]

Pls make solution of scale problem of 2020 advannce I have a hard time understanding it

[@hellohello4360]

Sir,Please make a list of questions that are relevant for jee advanced from pathfinder and SBT

[@PHYSICSSIRJEE]

Big job , no time , will try , can't promise

[@hellohello4360]

@@PHYSICSSIRJEE Thank you sir for responding🙏🙏

[@raviteja-ph4fx]

Sir, if we substitute R1 and R2 and R3 in formula and then find error, instead of substituting u and v in formula. Then error comes out to be different. Can you please explain.

[@PHYSICSSIRJEE]

It will be same , I guess . Did you calculate ? How much was the difference?

[@PHYSICSSIRJEE]

I have answered it in pinned comment

[@raviteja-ph4fx]

@@PHYSICSSIRJEE OK sir, thank you

[@seanparker798]

Will you please let me know the name of the writing software you use sir?

[@PHYSICSSIRJEE]

PDF annotator or open board

[@namanrustagi5190]

sir pls add more practice sets on your website

[@ShahrukhKhan-hg9jj]

🤩🤩🔥🔥🔥

[@ATOZ-jj6tm]

Sir for pure rolling is it v=r(omega) or a=r(alpha). Which one is true

[@sAiTAMa19478]

V= rw is necessary then we differenciate it

[@ATOZ-jj6tm]

@@sAiTAMa19478 thank you

[@as.if_0077]

Thank you sir

[@rushikesh_nale07]

Ok

[@mastermindiniit]

r u jee 2021 aspirant.

[@anishdatta698]

Sir...the solution which you showed as correct has one issue....the measurements are being done with 3 pins, not 4. So the error in measurement of u is actually not independent of the error in v. As you taught us in a previous video, if we mark L1 as 45cm, L2 75 cm, and L3 135cm, then u = L1 - L2, v = L3 - L2.....here L1, L2, L3 are independent, but u and v are clearly not independent as i stated earlier. If i solve with three variables instead of just u and v, then a different answer is coming (1.11%). As you explained in this video i took errors in each L1, L2, L3 as 0.25cm(LC).....please reply if this makes any sense. The solution you showed would be perfect for 4 pins, and not 3.

[@PHYSICSSIRJEE]

Yes , perfect thinking 👍🏼 and more correct way to do it . I have not checked your calculation , But 2LC is definitely wrong that JEE took🙂

[@anishdatta698]

Thank you sir

[@jeeenthusiast]

@@anishdatta698 shouldn't we take LC/2 as error in each L1,L2 and L3?

[@vaibhav5839]

u=-(R2-R1) and v=-(R3-R2) and then apply 1/f=1/v-1/u take log and differentiate,I got answer as 1.11 Am I right Sir🙏

[@aryanshrivastav4850]

Sir if u r seeing my comment... plz plz plz....take that error quest....of jee 2016 adv ... Of vernier calliper 2....it is not getting solved....naturally by finding least count....plz can u make that vdo by tomorrow???

[@PHYSICSSIRJEE]

Please post that in telegram or discord. Someone will reply. I am busy till Sunday with my students. All the best for your exam

[@aryanshrivastav4850]

@@PHYSICSSIRJEE telegram link sir

[@PHYSICSSIRJEE]

@@aryanshrivastav4850 it's in the description below latest video

[@aryanshrivastav4850]

@@PHYSICSSIRJEE group name plz sir....unable to access thru link

[@PHYSICSSIRJEE]

@@aryanshrivastav4850 use this 👇 telegram.me/joinchat/xk7TD1FgtjplZWE1

[@beluga8956]

🔥🔥

[@vedantjadhao8117]

❤️❤️❤️

[@Rishabh-se5yo]

Thanku so much sir ji Sir I have a doubt pls help and guide me whenever u will be free Sir my physics is not good and I have studied thoery but not able to apply it also not able to solve advance problem . Currently I am watching ur 2 videos daily Please help me sir so that atleast I am able to clear the cutoff of physics 🙏 it would be really helpful 😇

[@jgchaudhary1035]

😎😎

[@Algoner]

15 :23 ....it's like NTA of jee mains 🤣🤣🤣

[@sanchitmukherjee2410]

Op sir. 354 likes 0 dislikes. Ratio of like to dislike is infinity😍😍

[@kevinadesara356]

The only thing i dont like about nta or jee advance is this..

[@metablaze3523]

NTA ko roast karna to aap nahi chodenge🤣🤣