Unit 4 • Class 12Physics (Phy.102)
First Law of Thermodynamics
ऊष्मागतिकीको पहिलो नियम
Thermodynamic systems, indicator P-V diagrams, First Law dQ = dU + PdV, molar heat capacities Cp - Cv = R, isothermal, isobaric, isochoric, and adiabatic processes, adiabatic equation PV^γ = constant, work done calculations.
Lesson Summary & Key Concepts
Comprehensive thermodynamic formulation: work done during expansion, First Law dQ = dU + PdV, Mayer relation Cp - Cv = R, adiabatic equation derivation PV^γ = C, and reversible work calculations.
Textbook Exercises & Solutions
Showing 1 of 1 Solved QuestionsQuestion 1• 4 Marks
Quick Revision Takeaways
Common Exam Pitfalls to Avoid
⚠️ Common Error: Using PV = nRT to say P and V are inversely proportional in an adiabatic process.
✓ Correct Approach: In an adiabatic process, PV^γ = constant, NOT PV = constant.
Why: Temperature changes during adiabatic expansion; it is only constant in isothermal processes.
Content Provenance & Verification
Editorial Verified & Published
Original Author / ContributorNEB Notes Nepal Academic Team
Verified BySenior Subject Specialist (TU / NEB Panel)
Curriculum Versionv1.0 (CDC 2078/2080 Grid)
Last Verified Date2026-10-23
Legitimate Official Curriculum References
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