JNTU
JNTU B.Tech II THERMODYNAMICS Previous Question Paper (September/October - 2023 - R15)
Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions. iv) Use of approved steam tables, Mollier diagram, Psychrometric tables and Refrigeration are permitted.
Part A
Differentiate intensive and extensive properties.
Answer
Intensive properties are independent of the mass or size of the system (e.g., pressure, temperature, density). Extensive properties depend on the total mass or size of the system (e.g., total volume, total internal energy, mass).
What do you mean by thermal equilibrium?
Answer
Thermal equilibrium exists when the temperature is uniform throughout the entire system and does not change with time. When two systems are in thermal equilibrium with each other, there is no net heat transfer between them, implying they are at the same temperature.
What is Clausius inequality?
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Define principle of increase of entropy.
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Why do gases possess two specific heat values?
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Write down the Vader Waals equation of state.
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What is Dalton's law?
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What do you mean by adiabatic dewpoint temperature?
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Compare Otto and Diesel cycles.
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Define coefficient of performance of a refrigerator.
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Part B
Explain microscopic and macroscopic viewpoint of thermodynamic systems.
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Explain first law of thermodynamics applicable to flow and non-flow systems.
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What is irreversibility and state the causes of irreversibility?
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Derives steady flow energy equation for an open system.
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Derive the general expression for change of entropy for an ideal gas.
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A reversible engine is supplied with heat from two constant temperature sources at 900 K and 600 K and rejects heat to a constant temperature sink at 300 K. The engine develops work equivalent to 90 kJ/s and rejects heat at the rate of 56 kJ/s. Estimate the thermal efficiency of the engine.
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A domestic food freezer is to be maintained at temperature of -15°C. The ambient temperature is 30°C. If the heat leaks into the freezer at the continuous rate of 1.75 kJ/s, find the power required to pump this heat out continuously.
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Determine the entropy change undergone by an ideal gas when expanding adiabatically and irreversibly through a pressure ratio of 4 from an initial pressure of 700 kPa and temperature of 65°C according to the law pv1.2 = constant. Take Cp = 1.0035 kJ/kg K and ɣ = 1.4.
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Derive the Clausius- Clapeyron equation.
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Determine the rate of entropy production in the universe when the rate of heat transfer between a heat reservoir at 1650°C and another reservoir at 538°C is 2.15 × 109 kJ/hr.
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Explain the working of separating calorimeter.
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Explain the working of throttling calorimeter.
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Differentiate universal gas constant and characteristic gas constant. Provide their formulae.
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Compare volume expansivity, isothermal Compressibility and isentropic compressibility?
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Explain sensible heating and humidification processes.
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0.004 kg of water vapor per kg of atmospheric air is removed and temperature of air after removing the water vapors becomes 20°C. Determine the relative humidity. Assume that condition of atmospheric air is 30°C and 55% relative humidity and pressure is 1.0132 bar.
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Pressure and temperature of air at the entry to an Otto cycle are 1 bar and 300 K respectively. The compression ratio is 7.5. If the temperature of air after expansion is 550 K, calculate the thermal efficiency of the cycle.
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Explain dual combustion cycle with p-v and T-s diagrams?
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Discuss about the major components of a vapour compression refrigeration cycle.
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Explain the working of Bell-Coleman cycle.
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