Sign up now
to enroll in courses, follow best educators, interact with the community and track your progress.
Download
Course Overview, Understanding 1st Law of Thermodynamics (in Hindi)
10,007 plays

More
This lesson teaches meaning and mathematic statement of first law of thermodynamics and sign convention. Then it discusses the terms "change in internal energy" and "heat exchanged". Basically, it strives to build a foundation for the next lessons to be taught in this course.

Shubham Kumar
I have done B.Tech, IIT Delhi (in Mechanical engineering). I have been teaching physics to JEE and NEET aspirants for three years.

U
Unacademy user
thnku sir u teach very well..😊😊
Really a good lecture. Thank u very much sir.
Dheere dheere boliye sir
Shubham Kumar
10 months ago
aap video ki speed slow kar lijiye sir unacademy app pe
Sir can we ask doubts here
Shubham Kumar
a year ago
theoretical ones
Can we ask our doubts on whatsapp ?? Plz sir can u give you WhatsApp number
Shubham Kumar
a year ago
no dear
  1. Previous Lourses on Theimal Phys Thermo ' HeatTransber Neotom's Lans of oling 'Kinehic Theory of gases Ot Co (watch lesson 24 before starhngix Course..)


  2. This Course Contains.... First Lano o hermmo dynamics . understanding the terms n stL calcola tion of worK (Matenatical Graphical) Application Laonicludinggraph Ca t om o e ve roces) TSothermel procers A diabatic Process Polytropic Proces s Ther modu namic cycles 2nd Lauo of Thermody namics .Carnot's ycle, Engine Regngeration


  3. uppo ce, A pesson eata food and eh lo00 J of ene*gy tom it of hor K . Then He does 600 J Where does ret 400J It goes to your body 4 e stored y ts stored in haj We may see, Inkynal ener of increase by 400 Same happens to a themo dy namic system


  4. I We hawe a gaseous aystem as shown [AW Let, eadd 'g' amount of heat to it and it does W' amount of work Then, 8-u untgek lett inside it And Hence, (change in inkrnal enertr This is matematical stalement of 1+ Lend of Thermodynamiqs


  5. Sign Conven tion If heat is added to the System,+Ve heat rejeckd ty the syslem,g-ve System doex some work some work iu done on te ystem , Wve W -ve.


  6. Exam fle A cylinder piston ax contains some ga Whida does soJ of work Wh. le losing 30 J heat to the SuTroundings. Find chumse in internal energy of the system ec J0TK is done by gas,) 30 +so) = -80J so, U decreases 6 80J,


  7. Undes standing AU We have studied in KT<, (lesson-4) - f RT where n- no, of moles 2. degrees of freedom So 2- For same change in usiU hare sam e v lae of U. This is res pective of process a certain systenm 2- For a g4 for both paths because T -T depends on Point 1 42 and not on path I or 2


  8. o m via tw di tterent paths as shown. Ln path 2 7as rejects 20J of Heat and does 30 J o then find heat ad4edto qas in Path 1 CA Pat


  9. Sol ution In Path 2, 20 J Ruw 0 --soJ (Same as Path 1) -SOJ -


  10. Unders tandin mathe matieal In calorimethy we use 'n' more ften than m Y a as es So we detine. heat capacity i a path bunction, C wiu hawe diberent As Valuas for ibverent patha We wiu learn about C appy thexpession to calculata S Y all paths and then