(SEM-IID) THEORY EXAMINATION 2018-19 THERMODYNAMICS

Section A — Short Answer Conceptual Questions

Section A consists of a set of concise, concept-based questions designed to test the student’s fundamental understanding of thermodynamics. Each question requires clear definitions, explanations, or basic reasoning.

This section focuses on:

Basic laws of thermodynamics

Fundamental definitions such as system, state, properties

Differences between thermodynamic concepts

Pure substance behavior

Work & heat interactions

Thermodynamic equilibrium

Limitations and applicability of thermodynamic processes

These questions measure the student’s grasp of essential theoretical knowledge that forms the foundation for solving advanced thermodynamic problems.
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Section B — Analytical & Numerical Problem-Solving

Section B includes detailed numerical and analytical questions that require step-by-step application of thermodynamic laws.

One of the major numerical problems involves air compression, where air at:

100 kPa and 280 K
is compressed steadily to:

600 kPa and 400 K
with a mass flow rate of 0.02 kg/s and heat loss of 16 kJ/kg.

Students must compute the power input required to the compressor using the steady-flow energy equation, assuming negligible kinetic and potential energy changes.

This section tests:

Energy balance in open systems

Work and heat interaction calculations

Application of the First Law for steady-flow systems

Understanding of compressor processes in real-world engineering

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Section C — Long Answer Questions (Thermodynamic Cycles & Advanced Applications)

Section C focuses on larger thermodynamic systems and cycle analysis. The key problem describes two Carnot engines working in series between high and low temperature reservoirs (550 K and 350 K). Students must determine the intermediate temperature when both engines deliver equal power.

This question evaluates understanding of:

Carnot cycle efficiency

Temperature ratios

Reversible heat engine analysis

Ideal cycle performance

Other questions in this section may cover theoretical explanations, process analysis, entropy, and cycle efficiencies.