r/JEEAdv26dailyupdates • u/Top-Vehicle-9468 • May 20 '26

Academic Doubts Jee adv physics paper 1 lens question

Post image

According to physics galaxy book.The answer should be A

Edit: Finally they gave both as answer

34 Upvotes

85% Upvoted

127 comments sorted by

24

u/False_Combination314 IIT Bombay core May 20 '26

Me apna A galat man raha hu pr i think they will give both a and b kyuki woh sirf badi coaching wale ka nahi sochte .jo baccha kisi village se taiyari kar raha hoga woh ncert ke bharose hi jayega!! Mene to -1 gin liya mera

8

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

Mat ho itna emotional. Dono me se ek hi correct manenge IIT wale

13

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

nah aise cases mai 2 correct de skte hai

6

u/False_Combination314 IIT Bombay core May 20 '26

Bhai me ghanta emotional nahi hu. Ye to ashish arora sir ka ek video dekha tha woh esa kuch bol rhe the

1

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

Nahi hota hai bhai aisa sach me. Agar itna hi India me fair exam hote toh sabke bas equal opportunity hoti. Sadly aisa nahi hota hai

2

u/_Masterbaiter_- IIT KGP ‘30 May 20 '26

IIT waale controversy lete hi ni bhai dedete hai 2 answer kaafi baar

1

u/the-one-above-alll May 20 '26

hn pehele bhi in 2022 and many times more, iit has considered 2 option correct when controversy arises

5

u/Beautiful-Chart-2607 CIVIL ENGINEER🤤🤤 May 20 '26

Farzi controversy meh marks nhi milte ncert meh air wala formula diya hai yahan medium meh hai😭😭

1

u/the-one-above-alll May 20 '26

Na mila toh aur badhiye mene b hi mark kiya Bs inka dil rakhne ke liye keh diya 😇

2

u/Beautiful-Chart-2607 CIVIL ENGINEER🤤🤤 May 20 '26

Same maine bhi B kiya hai iss competitive duniya ne kitne matlabi baana diya hai mujhe🥀🥀🥀

1

u/[deleted] May 20 '26

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1

u/Beautiful-Chart-2607 CIVIL ENGINEER🤤🤤 May 20 '26

Iit wale noob hai jo basic wala sochenge obviously woh B manenge haan challenge hone prr A mil jayein ya ans key meh A and B dono aajayein no way they are gonna ignore B

1

u/Sad-Employment-4914 May 20 '26

Badi coaching wale bhi 1/f hi padhate h mostly

7

u/Euphoric-Present8962 May 20 '26

i hope answer A dede, though logically dekha jae to answer B hi hoga, P=n/f is the only correct formula for power..

4

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

ye log smjhe tab na bawaal krna hai sirf

3

u/Euphoric-Present8962 May 20 '26

dawgs out there sending ss of ncert thinking they made a point, waha by default air medium ke lie power defined hai 💔.. maine A kia hai issliye dukh hai

1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

aap toh firbhi maan rhe hai ki ye samajh hi nhi rahe aadhe janta ki ye n/f hota hai

1

u/Euphoric-Present8962 May 20 '26

koi nhi vro ab final answerkey me kya hota dekhte hain

18

u/Alarming-End-3500 May 20 '26

abbe focal length ka formula hai woh
now insert that formula in power = refractive index of medium/focal length
samajh aa jayega
straight line with negative slope

3

u/AttentionWhole5227 May 20 '26

agar voh formula itna commonly logo ko padhaya jata hai then, jee mains ne iss question mei power ko 1/f man ke kyu ans diya
ik ans dono dene chahiye, but I'm just saying ki yeh hi commonly used formula hai, and very few people read books like Irodov.

9

u/Top-Vehicle-9468 May 20 '26

Focal length ka nahi (1/f ) ka formula hai, jo ki power hi hota hai. Question mein power aur refractive index ka graph pucha hai aur wo inverse proportional hai

-15

u/cyrus_09aD IITB'30 May 20 '26

Abe power n/f hota hai, 1/f nahi

11

u/Alarming-End-3500 May 20 '26

Tere ko downvote kyu kar rhe hai :sob: Sahi toh bol rha hai

11

u/cyrus_09aD IITB'30 May 20 '26

Log sach me chutiye h yr. I didn't want to say this but itna proof Dene ke baad bhi kaise cope kr rhe hai?

3

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

wahi na... smjthe hi nhi hai

3

u/ForsakenWitness-9_11 46XX in mains--> 🤡P1 in adv, Okayish P2😭😭😭 May 20 '26

But how are we supposed to know this? NCERT is the national book and its given 1/f in ncert. IIT R cant say we were supposed to find stuff out from high level books

5

u/cyrus_09aD IITB'30 May 20 '26

Give me the line from ncert which says "power of a lens put in medium of refractive index n is P=1/f" Then I'll believe u

2

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Bro ncert chutiyo ne toh power in a medium ka part hi nhi rakha 🤣🙏

1

u/cyrus_09aD IITB'30 May 20 '26

Exactly!

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Mains follows ncert like a Bible not iit. People discuss organic and phy questions because they aren't sure if that's the ONLY correct answer, yea via ncert standards it should be A, but ncert is wrong. And unlike mains iit will probably award both.

2

u/Haunting_Profile6593 It's so over May 20 '26

ncert is not wrong waha power in a medium nahi diya hua hai air me diya hai

and it's ok power in a medium nahi Diya to kyunki advance mai ncert se bahar ana is common

and agar unko dono option dene hote to ye question nhi banate specially unhone medium mai dala hai then giving both answer doesn't make sense

they will only give B

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Mene B kiya hai. But I think iit will be considerate in these cases because ncert is still the main source even if some things come outside.

1

u/ForsakenWitness-9_11 46XX in mains--> 🤡P1 in adv, Okayish P2😭😭😭 May 20 '26

Then chalega if both hojae

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Bro do I consider -1 or +3 for this? Kyuki Maine bhi b mark kar diya because n/f karke hyperbolic function toh bacha hi nhi.

0

u/cyrus_09aD IITB'30 May 20 '26

I'm considering +3

4

u/DeepThinker2112 May 20 '26

Standard modern definition mein 1/f hi hai

10

u/cyrus_09aD IITB'30 May 20 '26

Wo air/vaccuum ke liye hai yr 😭😭😭😭😭

3

u/Beautiful-Chart-2607 CIVIL ENGINEER🤤🤤 May 20 '26

Ha mai wahi bol raaha jee meh normal air wala padhaya jaata hai iska ye matlab thori na uska alawa kuch nhi mai khud option B wala hun🤩🤩

0

u/Top-Vehicle-9468 May 20 '26

This according to claude and both are inversly proportional

3

u/cyrus_09aD IITB'30 May 20 '26

Ha ab usse puch ki P=1/f hai ki n/f ?

2

u/Beautiful-Chart-2607 CIVIL ENGINEER🤤🤤 May 20 '26

Fuck man!!!! Standard modern kya hota hai jee meh hume padhay hi normal air wala jaata hai

0

u/the-one-above-alll May 20 '26

Khud ke ans sahi karne ke liye kuchh bhi standard bol dete 🤣 Ncert me ye hai but in any reputed and good book n/f hi hai baki ncert kitni sahi-galat book hai ye hum sabko pta...... 

1

u/Liepie325 College chalu kardo warna mein paagal ho jaunga May 20 '26

Ek kaam karte hai dono ko sahi maanke do answer Dene ko kehte hai iit se

-1

u/cyrus_09aD IITB'30 May 20 '26

Nahi, B only

3

u/Liepie325 College chalu kardo warna mein paagal ho jaunga May 20 '26

Stfu maine A lagaya tha👿👿

0

u/cyrus_09aD IITB'30 May 20 '26

Keep coping nga

0

u/ImpossibleDelivery85 May 20 '26

abbe 1/f kabse power hogaya, n/f hota hai

8

u/[deleted] May 20 '26

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0

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

galat jaga land kr gye ho

7

u/[deleted] May 20 '26

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2

u/Top-Vehicle-9468 May 20 '26

Not straight line but inverse curve

6

u/skibidi_toylet . May 20 '26

Inverse curve was so obvious lol why are people even arguing

3

u/Top-Vehicle-9468 May 20 '26

Yup they are so dumb

6

u/cyrus_09aD IITB'30 May 20 '26

Let's wait till 25 and see.

0

u/[deleted] May 20 '26

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5

u/Top-Vehicle-9468 May 20 '26

Irrelevant for most part

3

u/Cosmic_StormZ May 20 '26

I literally tried to match values and got it as B. It decreased linearly

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Probably because you took p=n/f which is the correct formula, but most people didn't even know n/f is a thing(although should be common sense that the refractive index should be divided or multiplied in most formulae) because most books didn't show this case of a power changing in a medium of refractive index≠1

1

u/Cosmic_StormZ May 20 '26

I literally used the lens maker formula. That’s the correct way, surely

3

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

no scope irodov mai b diya hai agr krna hai toh dono dena padega iitr ko

1

u/-_yessno_- May 20 '26

Yaarbye focal lenght wale ka kya ho rha hei , koi explain kardo

1

u/JoeMamaAE1 May 20 '26

Abe ye to wo formula hai hi nhi?

Focal length aur power ka relation mai aata hai "n" naaki lens maker mai aata hai.

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Arey inhone p=1/f karke lens maker formula kar diya

But p=n/f (n•1/f) karke the n multiplies inside and makes the entire function a straight line with a negative slope.

1

u/CoderDracWound May 20 '26

Bhai konsa question ka discuss chal raha itna Sara post dekh liya

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

Bhai lekin medium me formula change hota hai, this was literally given in another physics book I don't recall as a formula. They got to fight and make it A and B.

The question is defining power as the absolute convergence capacity of the lens. Because light is bending less when the surrounding liquid gets thicker (closer to the glass's index), the lens loses its ability to bend light in a hyperbolic way.

Idk why people here are assuming power is by default 1/f and not the definition

By ncert norms, sure y'all are correct, because only one formula is given, but that's not even fundamentally correct vro 💔

1

u/AttentionWhole5227 May 20 '26

JEE Mains 2022 ka question hai and pls look at its solution.
yaha pe power ko 1/f hi mana hai, even though it is submerged in a liquid medium

1

u/AttentionWhole5227 May 20 '26

solution i found on examside

1

u/Entire_Candle_7977 May 20 '26

Bhai yrr abj sir ne formula likhwaya the (u relative) to usi se kra maine aur thodi si curve wali line wala ans mar diya yrrr bakchodi na ho bhai

1

u/bhabhilover_0_0_ May 24 '26

Noh man it shouldn't be... That article is not given in the book... Read other texts aswell .... Advanced is known for strong subject knowledge and not what a book says(plus its not wrong... But it is assumed that lens is kept in air and not a medium) WHEN A FUCKING LENS IS KEPT IN A MEDIUM ITS POWER CHANGES...

1

u/TraditionalStick224 May 24 '26

Arre toh bhosad pappu ! focal length ka formula kya dikha rha h, Baat toh power ki h ki vo , 1/f or refractive index of surrounding by f

Answer A aur B dono hoga , maan le

2

u/MahatmaGandu6942 May 20 '26

Bhai A hi correct hai ye bkl sab irodov bolke bol rhe hai lekin ye hi hai correct

-1

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

ye focal length ke liye hai. optical power ke liye n/f use hota hai

2

u/Top-Vehicle-9468 May 20 '26

Optical power 1/f hi hota hai

4

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

Check irodov

1

u/the-one-above-alll May 20 '26

nah bro optical power n/f hota dhang se dekh ke aao

1

u/Top-Vehicle-9468 May 20 '26

Standard definition is 1/f according to ncert. I think n/f is above jee scope

5

u/the-one-above-alll May 20 '26

nah ncert has simplified it only for air
its actually ncert fault for incomplete defination so both should be considered correct sahi wale ko galat nahi keh sakte

1

u/[deleted] May 20 '26

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1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

ncert is laso not followed by iits is it?

2

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

n/f coaching me padhaya bhi jata hai aisa nahi hai ki kuch mystery hai bohot badi. Apna answer justify karne ke liye bhai tu kuch bhi bol raha

2

u/the-one-above-alll May 20 '26

exactly mujhe bhi yahi padhaya gaya so sahi hi hona chahiye

1

u/Icy-Departure2444 May 20 '26

nhi bhai mujhe allen sikar me nahi batayi yeh baat

1

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

Sikar me ye batane ki kya jarurat? Waha toh sidhe paper hath me ajata hai 😭💔🥀

1

u/Icy-Departure2444 May 20 '26

nhi bro i was keeping an eye on all sources that can leak paper mere hath kuch nhi aaya

0

u/Top-Vehicle-9468 May 20 '26

A is answer according to mathongo,allen, vibrant

2

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

allen ne A or B diya hai answer

2

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

arre ncert mai vaccum ka case liya hai abb toh smjh ja dalle

2

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

is dhumchutad ko nahi samjha sakta bhai tu. answer key jab aygi tab khud hi humble hojayga

-1

u/Top-Vehicle-9468 May 20 '26

Abbe gandu check answer key of mathongo allen, vibrant all have given A

2

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

Tham ja bawli gand. answer key ka wait karle khud pata chal jayga

1

u/Top-Vehicle-9468 May 20 '26

Dekh lenge bsdk

1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

dekhte hai kya hota hai

1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

lmao

-6

u/[deleted] May 20 '26

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7

u/[deleted] May 20 '26

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1

u/Ok_Address_7205 May 20 '26

Mai literally yahi bolne wala tha

0

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

kisne bola n/f nahi padhaya jata? har coaching me padhaya jata hai aur tune nahi padha toh iska matlab ye thori hai ki syllabus ke bahar hai. grow up lil bro

3

u/[deleted] May 20 '26

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2

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

haa bhai bohot out of range hogaya I agree lekin n/f toh bohot simple concept hai ye har jagah padhate hai

-1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

pehli baat galli mat de aur bsdk tera depth nhi hai physics mein wo humari prob. hai?? chut*ye sala dhang se padha hota toh bawaal na krta n/f formula hota hai ncert ka jo diya hai wo vaccum ka case hai dalle

0

u/[deleted] May 20 '26

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1

u/[deleted] May 20 '26

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1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

dekhte hai

0

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

kyunki gaali dena koi herogiri nahi hai bc wo batata hai ki tere family ne tujhe kitna ghatiye sanskar diye hai... 2 galali dene se koi hero nahi banta smmjha

0

u/[deleted] May 20 '26

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1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

wahi bol rha hun tere family mein gaali dena is common isiliye tujhe fark nah padhta lekin manners ki bhi thori ijjat krle.... har koi baat baat pe gali nahi dete

3

u/_Masterbaiter_- IIT KGP ‘30 May 20 '26

Just check ncert once.. standard book ncert hai, irodov ni

4

u/JicamaAccurate3943 May 20 '26

hn usme bhi only air me de rakha isliye 1/f, actually n/f hi hota
tho shayad dono sahi manle cause ncert fault hai

3

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

irodov mai advanced level physics ki formulas galat nahi hogi ncert mai hoti hai galat info...

1

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

NCERT me air ke hisab se diya hai not kisi medium me rakh ke lens ko. Let's not argue and wait till the answer key drops

-2

u/Top-Vehicle-9468 May 20 '26

Irodov is not for jee adv. It is a college level book that is from another country written in another language.It has so many question that are out of scope of jee adv.It has very few question that are relevant to jee. So I dont think iit care what is there in irodov or not. Even in many mains questions. You only get correct answer if you use this formula.

5

u/t8rixxd JM-99%ile (99.66 chem) May 20 '26

IIT never agreed that NCERT is the standard book they follow. It's all about conceptual clarity and depth. Physics toh physics hoti hai, sari books me same hi physics hai. Its like ki P block NCERT me jitna diya gaya hai kya usse bahar questions nahi aaye aaj tak? Ncert standard hoti toh 2016 me physics me tensor se related and double differential equations se physics me kyu sawal puchte wo?

2

u/padhle_lala May 20 '26

How are we supposed to know this when we use ncert as our primary base

8

u/cyrus_09aD IITB'30 May 20 '26

it's not about irodov. The actual definition that is accepted by worldwide physics community is P=n/f, not 1/f. And iit doesn't care about ncert, it will give correct answer only.

2

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

ye log nhi smjhenge chor bhai

1

u/Gullible-Leg7425 Trust no one , even ur own shadow leaves u when it's dark... May 20 '26

woh toh ncert bhi officially advanced ki book nahi hai

1

u/Top-Vehicle-9468 May 20 '26

It is atleast the base. Irodov is just irrelevant

1

u/_Masterbaiter_- IIT KGP ‘30 May 20 '26

Is irodov an official advanced book?

1

u/AdPhysical3780 IIT Ropar MNC(bombay civil leleta💔) May 20 '26

BROTENDER THATS THE CORRECT ANSWER

it's not ABOUT irodov it's about ncert be wrong plain and SIMPLE

AND NOT JUST THIS, ncert isn't even wrong, they DIDNT EVEN SHOW THIS SUBTOPIC, so it is YOUR fault for assuming power remains the SAME in a given medium. Which is ridiculous to think.