JNTU
JNTU B.Tech II THERMODYNAMICS OF MATERIALS Previous Question Paper (December - 2018 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
Part A
Define Fick’s first law of diffusion.
Answer
Fick's first law states that the diffusion flux (J) is proportional to the concentration gradient (dc/dx). It is expressed as J = -D(dc/dx), where D is the diffusion coefficient, indicating that atoms move from regions of high concentration to low concentration.
Differentiate between steady state and non-steady state of different with examples.
Answer
In steady state, the concentration profile does not change with time (dc/dt = 0); an example is gas diffusion through a thin metal membrane at constant pressure. In non-steady state, the concentration at any point changes with time (dc/dt ≠ 0); an example is carburization of steel during heat treatment.
Which oxide on the Ellingham diagram shows downward slope? What does it represent?
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Give the limitations of Ellingham diagrams.
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Define partial molal quantity.
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Define and explain Sievert’s law?
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Define chemical potential?
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Define and explain solidus line and liquidus line?
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What is standard electrode potential?
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Differentiate between galvanic cell and concentration cell?
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Part B
Derive Darken’s equation? Give its importance.
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Explain the diffusion mechanism in metals.
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What is intrinsic diffusivity? Explain the determination of intrinsic diffusivity.
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Briefly describe the diffusion mechanism along grain boundaries and surfaces?
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Draw and explain the important features of Ellingham diagram.
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Give the important uses of Richardoson’s diagrams.
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What is equilibrium partial pressure of oxygen? Explain its importance with respect to Ellingham diagrams?
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Ellingham diagrams are useful in the extraction of iron and in alumino thermic process. Explain how?
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Derive Gibbs-Duhem equation and give its importance.
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What is excess thermodynamic quantity? How is determined? Explain.
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Explain the importance of integration of Gibbs-Duhem equation.
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Differentiate between ideal and non-ideal solutions.
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Briefly describe the application of thermodynamics to phase diagrams.
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Explain the meaning of equality of chemical potential in equilibrated phases?
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Explain the importance of liquidus line and solidus line during solidification of a eutectic alloy?
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Derive Nernst equation to determine the EMF of a cell?
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Explain Galvanic cell with a neat sketch.
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Explain the application of Gibbs-Helmholtz equation to galvanic cells?
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With a neat sketch explain concentration cell?
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