15 EXAMPLES BASED ON FIRST LAW OF THERMODYNAMICS | IIT ADVANCED | JEE MAIN | CHEMISTRY CLASS 11

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  • เผยแพร่เมื่อ 24 ธ.ค. 2024

ความคิดเห็น • 107

  • @PadhleBSDK-164
    @PadhleBSDK-164 2 หลายเดือนก่อน +7

    For those who are stuck on 2nd question:
    It is easy to understand that the order of final pressures is:
    II > I > III and IV > III.
    But we need to compare IV with I and II to write our final answer.
    Now bear with me, this is the longest part of this question:
    Let's compare I and IV
    In I:
    We know since isothermal,
    PiVi = Vf * (Pf of I)
    Pf of I = PiVi/Vf (mark this equation)
    In IV: Adiabatic, Q=0
    ΔU = W
    n(Cv)ΔT = -(Pext)(ΔV)
    n(Cv)Δ(PV/nR) = -(Pext)(ΔV)
    (n(Cv)/nR)Δ(PV) = -(Pext)(ΔV)
    Δ(PV) = -(Pext)(ΔV)*R/(Cv)
    opening this bulls**t(i dont want to type) you will get in the end:
    Pf of IV = (PiVi/Vf) - {(Pext)(ΔV)*R}/{(Cv)(Vf)}
    in this equation above, in RHS
    1st term is Pf of I
    2nd term is >0
    Hence proved:
    Pf of IV < Pf of I
    So final order: II > I > IV > III

  • @harshitbarthwal8081
    @harshitbarthwal8081 4 ปีที่แล้ว +20

    Ab meri frequency apke sath match karne lg gyi mene pahle ps sir ke lecture dekhe but he is also best teacher and you are also best and awesome teacher🙏🙏🙏🙏🙏🙏❤️❤️❤️❤️❤️❤️

  • @sst940
    @sst940 4 ปีที่แล้ว +24

    Sir, in the 2nd que we know that final pressure of irr. Adi. Process is more than that of rev. Adi. Process.
    Above is correct...
    But final pressure is how much more than rev. adi. Process is not known. Then how can we comment that final pressure of irr. Adi. Process is less than final pressure of irr. isothermal process And that of rev. Process of p^2v=const..... Hence we can't comment on exact position of final pressure of irr. Adi. Process... Is n't it???
    Just we can say that it is more than that of rev. Adi. Process......

    • @kpghac8544
      @kpghac8544 4 ปีที่แล้ว +9

      It's like adiabatic is always below isothermal in case of expansion

    • @optimus223
      @optimus223 3 ปีที่แล้ว +11

      It is given in the question that gases are expanding and all are allowed to double their volume which means all will have the same volume after expansion which implies this is a situation of expansion at same final volume and in this case steepness of isothermal adiabatic is more than that of isothermal reversible...which sir illustrated graphically in the previous lecture...
      Hope you get it

    • @in_ashish
      @in_ashish 3 ปีที่แล้ว

      bhai ask your queries on telegram group of ALK sir.

    • @kingmysterio2349
      @kingmysterio2349 ปีที่แล้ว

      @kpghac is it also valid for cases of irreversible expansion like sir demonstrated for reversible expansion and I got it but didn't get the irreversible one

    • @kingmysterio2349
      @kingmysterio2349 ปีที่แล้ว +1

      @@in_ashish idk but I am not able to access sirs group in telegram

  • @Kokoro_watari
    @Kokoro_watari วันที่ผ่านมา

    2nd question 😧, between adiabatic irrev n adiabatic rev could we also not use that if the final volume of both the process is same then the process in which final temp is greater will have greater pressure, so hence 3 is irrev

  • @jumphigh7453
    @jumphigh7453 2 ปีที่แล้ว +9

    I think 2nd question is incorrect. The more gamma will be the more steep the graph will be as:
    PV^γ is constant (say K), then.
    P=K/(V^γ) the higher the power of V (which is γ here) the greater the denominator and lesser will be P making it more steep.

    • @chacha6438
      @chacha6438 ปีที่แล้ว

      Tera gamma half hai less than 1

    • @fiitjeejee
      @fiitjeejee ปีที่แล้ว +1

      Differentiate PV^gamma... you will get dP/dV = -gammaP/V.... so greater tha gamma, more steep the curve

    • @akritisingh5645
      @akritisingh5645 ปีที่แล้ว +1

      Yeah this same doubt is mine

    • @sahilkumar5086
      @sahilkumar5086 ปีที่แล้ว +2

      More the value of gama more the graph will be steep ? is it right ?

    • @divyam7037
      @divyam7037 6 หลายเดือนก่อน

      ​@@sahilkumar5086yes it is correct dont believe these idiots they're trying to confuse you

  • @kanpuriyan9679
    @kanpuriyan9679 4 หลายเดือนก่อน

    2:56 4:52 8:29 7:40 9:41 13:05 16:00

  • @aviralshukla15
    @aviralshukla15 ปีที่แล้ว +8

    More gamma more steepness

  • @Alice-eq4oh
    @Alice-eq4oh 3 ปีที่แล้ว +9

    Sir is 17:45 min.
    Heat capacity is in j/degree celcius and temperature is in Kelvin,
    Is there no conversation of temperature from celcius to Kelvin

    • @amitsingh2782
      @amitsingh2782 3 ปีที่แล้ว +2

      Are change in degree is equal to change in farenheight

    • @cosMYs891
      @cosMYs891 3 ปีที่แล้ว

      @@amitsingh2782 *Kelvin

  • @kushagrasharma6679
    @kushagrasharma6679 2 ปีที่แล้ว +2

    12:45 Irreversible adiabatic rev se to upar hi hoga but l and ll condition se niche kyu hoga???? Ye jruri kyu hai please anyone explain

    • @arjunjain9498
      @arjunjain9498 2 ปีที่แล้ว

      Hey, i also had the same doubt, did u get the answer to it?

    • @K_PRIYAM
      @K_PRIYAM 2 ปีที่แล้ว

      Because adiabatic process H

    • @IITian-zy7ks
      @IITian-zy7ks 10 หลายเดือนก่อน

      1 condition isothermal hai constant final volume hai toh steepness of adiabatic zyada hogi thar isothermal

    • @mauryaanjani
      @mauryaanjani 2 หลายเดือนก่อน

      Kyuki reversible adiabatic ki equation hoti h PV^gamma = const aurr gamma ki value hamesha 1 se badi hoti hai jo ki baki process me se sabse jada thi isliyee

  • @roopasharma32
    @roopasharma32 4 ปีที่แล้ว +11

    sir in the first question since adiabatic reversible process, del(U)=WORK DONE so since dv for all is same more work done = more area under graph and del(u)= Cv so f/2 ratio highest in polyatomic molecule hence most area under graph ...is this also the right explaination sir?

    • @nownow1025
      @nownow1025 4 ปีที่แล้ว

      Yes, I also have used the same method.

    • @AThousandSunsinphysics
      @AThousandSunsinphysics ปีที่แล้ว

      samja nhi

    • @mrawesomexd6969
      @mrawesomexd6969 3 หลายเดือนก่อน

      Yep it works but just one correction, del U is directly proportional to Cv (del U= nCv delT) and not del U=Cv

  • @godspeed8866
    @godspeed8866 2 ปีที่แล้ว +8

    Wrong from 11:00

    • @xyz_ytc
      @xyz_ytc 2 ปีที่แล้ว +3

      Yess jiska jitna jyada gama hoga utni hi jayad steepness hogi.

    • @divyam7037
      @divyam7037 6 หลายเดือนก่อน

      IIT nahi tum ITI ka form bharo pagal khud kuch aata nahi sir ko galat bta rha hai

  • @ronakbhandari8836
    @ronakbhandari8836 8 หลายเดือนก่อน +2

    HOW DID YOU COMPARE BETWEEN IRREVERSIBLE ADIABATIC AND IRREVERSIBLE ISOTHERMAL?

    • @notBetu
      @notBetu 7 หลายเดือนก่อน

      same doubt my brother

    • @divyam7037
      @divyam7037 6 หลายเดือนก่อน

      same doubt my brother

    • @anonymousyt3547
      @anonymousyt3547 6 หลายเดือนก่อน

      previous lectures dekho
      work done by an irreversible process is greater than the reversible process

    • @mrawesomexd6969
      @mrawesomexd6969 3 หลายเดือนก่อน

      Work done by isothermal is always greater than adiabatic as more area under curve for isothermal. And that's why adiabatic has greater slope. Or u can say in isothermal PV=const comparing with PV^x=const slope is 1 whereas in adiabatic it's PV^gamma=const and sir mentioned gamma>1 hence greater slope for adiabatic

    • @zentrox852
      @zentrox852 5 วันที่ผ่านมา

      @@mrawesomexd6969theres one case though where adiabatic work is more than isothermal. in compression, when final volume is same.

  • @vedanttambe5781
    @vedanttambe5781 4 ปีที่แล้ว +5

    Sir in last qt. , C is in J/°C so we must convert it into J/K and then apply Q = C×dT ???

    • @rakeshkumarsrivastava4835
      @rakeshkumarsrivastava4835 4 ปีที่แล้ว +2

      yes...it was by mistake and it can be easily understood by any serious aspirant

    • @NOOBCRASTINATOR69
      @NOOBCRASTINATOR69 2 ปีที่แล้ว

      The value will still be same

    • @Anonymous-ez9qn
      @Anonymous-ez9qn ปีที่แล้ว +1

      It's so simple to understand, we do C×dT. Dt is change in temperature, change will be same in both scales so what sir did is absolutely correct.

    • @pranav3833
      @pranav3833 10 หลายเดือนก่อน

      No no, it's per degree and we know that change in temp. is the same both in Kelvin and Celsius scale right, so it won't make any difference.

  • @alphaiitd1
    @alphaiitd1 3 ปีที่แล้ว +3

    Great illustrations sir

    • @izyanjamal7717
      @izyanjamal7717 9 หลายเดือนก่อน

      are you in IIt delhi?

  • @ujjwal112_13
    @ujjwal112_13 3 ปีที่แล้ว +4

    Sir at 12:40 why didn't we use the property that |W|rev > |W| irrev

    • @IITian-zy7ks
      @IITian-zy7ks 10 หลายเดือนก่อน

      this property is holding true for the given question .. magnitude of rev expansion zyada hai doesnt mean ki rev ka point upar aayega it means that area under curve zyada hoga reversible wale graph ka...reversible wala graph close to rectangular hyperbola hai aur irreversible wale ka work done rectangular area hai toh end me graph banake dekho samaj aajya reversible ka area hi zyada hai point niche hone ke bawjud..yaha par temp of irr more than tem of rev wala property use hua hai..volume constant toh temp more toh pressure more

  • @soumikbhattacharya4646
    @soumikbhattacharya4646 ปีที่แล้ว +2

    but sir? why didnt we take number of moles as 0.4, instead considered it 1? And sir why is it wrong to take the number of moles as 1?

  • @pranavprabhu1600
    @pranavprabhu1600 ปีที่แล้ว +1

    Thank You sir🙏🙏🙏🙏

  • @sanya8525
    @sanya8525 9 หลายเดือนก่อน +1

    In the second question, we have PV^1/2 (for reversible process) and PV (for irreversible and reversible both) , so as sir said More thr value of X, lesser is the steepness, then why is isothermal irreversible process is having greater steepness than reversible process with PV^2 ???

    • @sanya8525
      @sanya8525 9 หลายเดือนก่อน +1

      *P^2V(reversible process)

    • @Dev-i8r
      @Dev-i8r 7 หลายเดือนก่อน +1

      GALAT BOL DIYA SIR NE LEKIN TUMNE LAST VIDEO ME DERIVATION NHI DEKHI KYA JITNA JAYADA X UTA STEEP

  • @harshitbarthwal8081
    @harshitbarthwal8081 4 ปีที่แล้ว +4

    Mujhe ye pv ki power gama vala concept samj ni aata someone suggest me please what to do

    • @lovephysicswithrahul7689
      @lovephysicswithrahul7689 4 ปีที่แล้ว +4

      Dekh bro, agar PV me V ki power gamma ho to adiabatic reversible process hota hai. Agar Khali PV diya ho to isothermal process Hota hai. also (additional concept) agar kisi process ka c nikalna ho to c=cv+R/(x-1) karde agar koi general relation diya ho to P and V key terms me.
      Baaki to easy hai vro...

    • @dhruvdeshwal3107
      @dhruvdeshwal3107 4 ปีที่แล้ว +3

      Agar process sirf reversible ha to PV^X ma more the X Less the stiffness . aur agar process adibiatic rev ha to PV^X more the X more the stiffness hoga . Plz correct me If I am wrong

    • @kpghac8544
      @kpghac8544 4 ปีที่แล้ว +3

      @@dhruvdeshwal3107 i think it's wrong

    • @akritisingh5645
      @akritisingh5645 ปีที่แล้ว

      ​@@kpghac8544 Then what is correct? Please explain if you have understood it 🙏

    • @Akxxshmxxx
      @Akxxshmxxx ปีที่แล้ว

      u must start sudying.......

  • @dalishanagpal8230
    @dalishanagpal8230 2 ปีที่แล้ว +6

    sir in the last question why did we took moles = 1 when they are coming 0.4. also why did we not use the formula:
    delta H = n c delta t
    as u said earlier that this formula is applicable for any process for ideal gas

    • @chacha6438
      @chacha6438 ปีที่แล้ว

      C kaise nikalega

    • @nehadhumal7551
      @nehadhumal7551 ปีที่แล้ว +1

      Woh n cp delta t hota hai. Cp nahi diya question me

    • @SiddharthSingh-id9fb
      @SiddharthSingh-id9fb ปีที่แล้ว

      1.Sir didn't use no of moles anywhere in this question.
      2.We are studying thermodynamics for a closed system so no of moles will remain constant.
      3.When no of moles are constant the combined gas equation states that P1V1/T1=P2V2/T2.
      If you have doubt regarding this formula,I advice you to watch the "states of matter" playlist.

    • @physicslover6967
      @physicslover6967 ปีที่แล้ว

      @@SiddharthSingh-id9fb bro ush ne pucha hai ki when u solve p1× v1/T1×R you will get 0.4 but sir took it 1 mole

    • @ayush_5096
      @ayush_5096 7 หลายเดือนก่อน

      ​@@SiddharthSingh-id9fbQ = nC∆T and not C∆T as i guess

  • @gigastein3151
    @gigastein3151 2 ปีที่แล้ว +2

    Sir In 2nd question How did you compare Rev process P^2V= constant and Irre adia process

  • @csdoit
    @csdoit ปีที่แล้ว

    10:59 - 11:09

  • @NAIR-X
    @NAIR-X 3 ปีที่แล้ว +1

    10:00

  • @prismaticincredibles7152
    @prismaticincredibles7152 2 ปีที่แล้ว +1

    In the IV part it is given that isothermic adiabatic at constant " ext. Pressure" but in sir's graph it is made as at constant volume. Isn't?
    I've this doubt if anyone have explanation regarding it then please explain me.

    • @gigastein3151
      @gigastein3151 2 ปีที่แล้ว

      @@Future_iitian_ Yes graph of irreversible process only accounts for amount of work done not how the process continues unlike smooth curves of reversible processes which exactly gives us the equation of path.

    • @HarishKumar-yr9gv
      @HarishKumar-yr9gv ปีที่แล้ว

      Yeah because ita againiat constant external pressure and in the graph its intsrnal pressure vs volume graph not external pressure

    • @AThousandSunsinphysics
      @AThousandSunsinphysics ปีที่แล้ว

      so what is correct?

  • @KavishSethi-qm3iy
    @KavishSethi-qm3iy ปีที่แล้ว

    9:20

  • @aruntejachamalla7465
    @aruntejachamalla7465 4 ปีที่แล้ว +2

    🔥 🔥 🔥 🔥 🔥

  • @SANDRA-xq7es
    @SANDRA-xq7es ปีที่แล้ว

    Sir in 1st ques PV^(gamma) is applicable for ideal gases only... so why we use it here... tho if we consider these gases to be real then too answer comes the same... but idk if we can use PV^(gamma)=k

    • @IITian-zy7ks
      @IITian-zy7ks 10 หลายเดือนก่อน

      when in the question nothing is said about the idenity of gases we treat them as ideal

  • @nitinpandey2614
    @nitinpandey2614 ปีที่แล้ว

    At 10:40 sir said that more x less steepness ..
    Can someone explain

    • @IITian-zy7ks
      @IITian-zy7ks 10 หลายเดือนก่อน

      sir actual meant x zyada toh steepness (close to vertical line) zyada
      for example ek equation lets say is PV=k
      differentiate .. VdP + PdV=0
      dP/dV = -P/V
      another eq lets say PV^2= k (adiabetic reversible process eq)
      differentiate..P2VdV+ V^2dP=0
      dP/dV = - 2p/v
      so slope of 2 eq is more which means it is more sttep

  • @sonalkumari8096
    @sonalkumari8096 ปีที่แล้ว

    SIR if C = 50J/C then why you did not opt delta in celcius instead of kelvin

    • @sonalkumari8096
      @sonalkumari8096 ปีที่แล้ว

      Someone please clear

    • @aayushranjan1686
      @aayushranjan1686 ปีที่แล้ว +1

      temperature difference in degree celcius and in kelvin is the same

  • @sonamverma2225
    @sonamverma2225 2 ปีที่แล้ว +3

    In 1st Que,sir ne kha more Gama to more stipnes but in 2nd
    More Gama to less stipnes ye kya hai .samajh se bahar

    • @devsharma3331
      @devsharma3331 ปีที่แล้ว

      same doubt

    • @akritisingh5645
      @akritisingh5645 ปีที่แล้ว +1

      Same confusion bro!! Did you get the answer?

    • @KaleshAbhijeet
      @KaleshAbhijeet ปีที่แล้ว

      agar tmhara doubt clear ho gya ho doubt to mujhe bhi bata do,, same doubt

    • @khayatishree1389
      @khayatishree1389 ปีที่แล้ว +3

      ​@@KaleshAbhijeetsir ne galti se bola par solve sahi kiya 1/2 is less than one isliye uski steepness kam hogi isothermal se bcs 1>1/2 "more the gama more will be the steepness"

  • @gamersarena693
    @gamersarena693 ปีที่แล้ว

    14:18

  • @gigastein3151
    @gigastein3151 2 ปีที่แล้ว

    Sir Q 3 mai apne ye nhi btaya ki gases are ideal or not, real bhi to ho skti h, to T2 kaise determine krte.

    • @devsharma3331
      @devsharma3331 ปีที่แล้ว +1

      agr mention na ho to ideal gas hi maante hai(default)

    • @eforeverything6482
      @eforeverything6482 ปีที่แล้ว

      Where are. You now

  • @loneboy2807
    @loneboy2807 ปีที่แล้ว +1

    sir in ques 2nd i didnt understood the Iso irreversible wala part as we know irrev and rev iso thermal both end up at same final state but final state can be 3 or 4 also so why you choose only second position please anyone explain me 🛑🛑🔴

    • @ankitakhare4988
      @ankitakhare4988 ปีที่แล้ว

      Bcoz iso thermal mai. PV ki power 1 hoti h hmesha

  • @shivamshaw_07
    @shivamshaw_07 ปีที่แล้ว +2

    ❤😊

  • @sst940
    @sst940 4 ปีที่แล้ว +6

    Sir, in the last que no. Of moles is not given and also not mentioned the gas as ideal then how you took no. Of moles =1 and used( p1v1/T1)=(p2v2/T2)....... please clarify this doubt sir!!!

    • @cr7fan481
      @cr7fan481 4 ปีที่แล้ว +1

      Bro no. of moles are constant and equal to both P1V1/T1 and P2V2/T2
      Hence P1V1/T1 = P2V2/T2

    • @bhavayluthra2381
      @bhavayluthra2381 4 ปีที่แล้ว +6

      @Divesh Arora if nothing is mentioned the gas is assumed to be ideal gas

    • @dhruvdeshwal3107
      @dhruvdeshwal3107 4 ปีที่แล้ว

      @@cr7fan481 sir n=1 kasa liya formula ma

    • @vivekdhaka2201
      @vivekdhaka2201 4 ปีที่แล้ว +2

      Yes I think it is small mistake by sirs side no of moles =1/250 so answer will be different

    • @PriyanshuKumar-dv5wl
      @PriyanshuKumar-dv5wl ปีที่แล้ว

      Are heat to change hoga na
      Q=nC∆T

  • @PriyanshuKumar-dv5wl
    @PriyanshuKumar-dv5wl ปีที่แล้ว

    Q=nC∆T hota hai na
    Sir ne to moles use hi nhi kiya third que me

    • @pushkarsharma1167
      @pushkarsharma1167 ปีที่แล้ว

      May be question data is about molar heat capacity.

    • @Kokoro_watari
      @Kokoro_watari วันที่ผ่านมา

      Yes i thought that too

  • @amitsingh2782
    @amitsingh2782 3 ปีที่แล้ว +1

    ❤️❤️❤️