JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV CHARACTERIZATION OF NANOMATERIALS Previous Question Paper (July - 2023 - R16)
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.
Part A
Mention the uses of electron microscope in materials analysis.
Answer
Electron microscopes are used for high-resolution imaging of surface topography, determination of crystal structure, and analysis of chemical composition at the nanoscale.
Define magnification. How it is related to focal length of a lens?
Answer
Magnification is the ratio of the size of the image to the size of the object. For a thin lens, it is related to the focal length (f) and the object distance (u) by the formula M = f / (u - f).
How the electron microscopes are used to obtain the composition of sample using Energy Dispersive Analysis of X-rays (EDAX) technique?
Answer
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Summarize the importance of accelerating voltage, convergence angle and beam current in SEM analysis.
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What is bright – field image in Transmission Electron Microscope (TEM)?
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What is electron diffraction? Mention the conditions and applications of diffraction.
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Write notes on the classification of forces between atoms at the tip and the specimen sample in Atomic Force Microscope (AFM).
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What is the working principle and instrumentations used in AFM?
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What is the working principle and uses of UV Spectroscopy?
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What is peak broadening in XRD analysis? Mention the reasons for peak broadening.
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Part B
Explain the terms “resolution” and “depth of focus” of a microscope.
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Discuss the uses of electrostatic lens and electromagnetic lens in electron microscopy.
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With a schematic diagram, explain the working theory, operating principle and applications of optical microscope.
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What are the advantages and limitations of optical microscope?
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With a neat sketch, discuss the theory of operation and instrumentation parts of scanning electron microscope.
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What are the causes of secondary electrons and characteristic X-ray in scanning electron microscopy (SEM)?
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Discuss the applications, advantages and limitations of scanning electron microscope (SEM).
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Explain the procedure for preparing biological samples in SEM.
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With neat sketch, discuss the operating theory and working principle of Transmission Electron Microscope (TEM).
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Mention the applications of TEM.
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Discuss the principle of “dark field imaging” mode of operation for TEM.
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Explain the instrumentation parts and working principle of High Resolution TEM (HRTEM).
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Explain the principle of tapping, contact and non – contact modes of imaging in Atomic Force Microscope (AFM).
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Discuss the methods of “tip functionalization” in Atomic Force Microscope (AFM).
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What are force-distance curves? Mention the importance of this curve.
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Explain the working principle and uses of single crystal X-ray diffraction technique.
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Discuss the working principle and uses of Raman spectroscopy.
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State and explain Scherer formula and Williamson – Hall equation.
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Discuss the causes of micro strain in crystalline material. How it affects the properties of a crystal?
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