First Law of Thermodynamics — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in First Law of Thermodynamics.

Combined Process Analysis with P-V Diagrams

high

NEET frequently tests the ability to analyze multi-step thermodynamic processes represented on P-V diagrams. A question might involve a gas undergoing an isobaric expansion, followed by an adiabatic compression, and then an isothermal compression back to the initial state. Students would need to calculate $\Delta U$, $Q$, and $W$ for each step and for the entire cycle, requiring a strong understanding of all process types and their graphical representation. This tests both conceptual understanding and calculation skills, making it a comprehensive question type.

Conceptual Comparison of Work Done in Different Expansions

medium

A common conceptual trap involves comparing the work done or heat exchanged in different processes (isothermal, adiabatic, isobaric) between the same initial and final states (or volumes). Questions might ask which process does the most work, or which leads to the largest temperature change. This requires a clear understanding of the slopes of P-V curves for different processes and their implications for energy transfer, without necessarily requiring complex calculations. It tests fundamental conceptual clarity.

Application of Mayer's Relation and Atomicity

high

Questions involving specific heat capacities ($C_P$, $C_V$) and their ratio ($\gamma$) are very common. A predicted angle is to combine Mayer's relation ($C_P - C_V = R$) with the atomicity of the gas (monatomic, diatomic, polyatomic) to determine unknown quantities. For example, given the work done in an adiabatic process, calculate the temperature change, requiring knowledge of $\gamma$ for the specific gas. This tests the ability to integrate multiple formulas and concepts.