Experimental Techniques in Metallography Mid - I, September - 2014

1.The smallest object detail that can be resolved with a microscope with light 589nm wavelength is 3.5Χ10-7. Find the resolving power of the microscope
  • 2.85Χ106
  • 1.5Χ106
  • 0.5Χ106
  • 1.85Χ106
Answer: C
2.Calculate the wavelength of an electron moving with a velocity of 103m/s. (h = 6.6Χ10-34Kg m2/s and mass of electron is 9.1Χ10-31Kg)
  • 8.25Χ10-7m
  • 10.25Χ10-7m
  • 7.25Χ10-7m
  • 14.25Χ10-7m
Answer: D
3.The wave nature of electrons is proposed by .
  • Heisenberg
  • Pauli
  • Schrodinger
  • de Broglie
Answer: D
4.Which of the following will carry the complete image of the specimen by electron beam
  • Light microscope
  • Reflected Microscope
  • SEM
  • TEM
Answer: C
5.Electrons are generated in an electron microscope by a process known as
  • Diffraction
  • Scattering
  • Thermionic scattering
  • Collisions
Answer: C
6.The major disadvantage of TEM is
  • Specimen thickness < 100 nm
  • Specimen should be powder
  • Specimen should be single crystal
  • Specimen should be poly crystalline
Answer: A
7.Electrolytic polishing is not used for _________________
  • Grey cast irons
  • Aluminium
  • High Mn steels
  • Single phase alloys
Answer: B
8.Microscopic examination of a polished surface reveals ______before etching
  • Microstructure
  • Inclusions
  • Grain size
  • Phases
Answer: B
9.The ability of an objective to produce sharply defined separate images of closely spaced detail in the object is termed as
  • Numerical aperture
  • Resolving power
  • Objective
  • Eye piece
Answer: D
10.The total magnification of microscope depends on
  • Tube length
  • objective and tube length
  • Eye piece and tube length
  • objective, eye piece and tube length
Answer: D
11._________________________ is defined as the ratio of the linear size of the image to the linear size of the object.
Answer: MAGNIFICATION
12.When an electron interacts with the matter, no energy is transmitted from electron to the matter is called as _____________________ interaction.
Answer: ELASTIC
13.Any diffraction pattern of a crystal is a map of ____________________ of the crystal where as the microscopic image is a map of crystal lattice.
Answer: RECIPROCAL LATTICE
14.__________________ is used to correct the minor imperfections in the objective lenses of electron microscope.
Answer: STIGMATOR
15._____________________ is an electrical component that produces an electron beam that has a precise kinetic energy and used in TEM.
Answer: ELECTRON GUN
16.The micro structure properly etched to observe at a low magnification will appear to be _________ at a high magnification.
Answer: OVER ETCHED
17.__________________ illumination is used where contrast due to bright or dark field illuminations is poor.
Answer: OBLIQUE
18.The ability of an objective to produce sharply focused image when the surface of the object is not truly plane, this is called as _____________________.
Answer: DEPTH OF FOCUS
19.__________________________ is inversely proportional to the numerical aperture and the magnification of the objective and cannot be changed for a given objective.
Answer: VERTICAL RESOLUTION
20._________________ lenses are used to reduce spherical aberrations.
Answer: PLANO-CONVEX