X-Ray Metallography Mid - I, September - 2014

1.Each diffracted beam in the Laue method has a __________.
  • Different wavelength
  • Constant wavelength
  • Fixed planar spacing
  • Fixed Bragg angle
Answer: A
2.White radiation is used in
  • Laue method
  • Diffractometer
  • Rotating crystal Method
  • Focusing cameras
Answer: A
3.Resolving power of Seemann – Bohlin camera is
  • Directly proportional to sin Ө
  • Directly proportional to Sin2 Ө
  • Inversely proportional to 2Sin Ө
  • Directly proportional tan Ө
Answer: D
4.Resolving power of a focusing camera is defined as
  • 4R/ΔU
  • d/Δd
  • Δλ/λ
  • U/R
Answer: B
5.The other name for pinhole photograph is
  • Laue photograph
  • Back-reflection photograph
  • Radiation photograph
  • Flat-plate photograph
Answer: D
6.Bragg’s law shows that the __________ is the wavelength, the smaller the Bragg angle for planes of a given spacing.
  • Shorter
  • Maximum
  • Greater
  • Constant
Answer: A
7.Incoherent scattering becomes more intense as the _________ of the specimen decreases.
  • Mass number
  • Atomic number
  • Applied current
  • Thickness
Answer: B
8.In Debye-Scherrer method, the film is placed on the __________of a cylinder and the specimen on the __________of the cylinder.
  • Surface, surface
  • Surface, axis
  • Axis, axis
  • Axis, surface
Answer: B
9.In focusing method, the film, specimen and x-ray source are placed as.
  • Film on the surface and specimen and X-ray source on the axis of a cylinder
  • Specimen on the surface and film and X-ray source on the axis of a cylinder
  • All three on the surface of a cylinder
  • All three on the axis of a cylinder
Answer: C
10.The powder camera is superior to a diffractometer when
  • An entire ring must be recorded
  • A partial ring is sufficient to record
  • The specimen is large, heavy or immovable
  • Only a small amount of sample is available.
Answer: A
11.The intensity of any characteristic line depends on both _____________ and _______________.
Answer: Tube current I and the amount by which the applied voltage exceeds the critical excitation voltage (V-Vk)
12.H. G. Moseley found that the wavelength of any characteristic line _________ as the atomic number of the emitter increased.
Answer: Decreased
13.The origin of the characteristic spectrum lies in the _________________.
Answer: Atoms of the target material
14.The linear absorption coefficient of a material is proportional to _______________
Answer: Density
15.X-rays are produced from _____________. (Surface of electrode/interior part of the electrode).
Answer: Surface of electrode
16.The three causes of line broadening are ____________, _____________ and ______________.
Answer: Small crystallite size, nonuniform strain and stacking faults
17.During recovery stage of a cold worked metal, both macro- and micro-residual stresses are ______________in magnitude.
Answer: Reduced
18.If a diffraction line is spotty on a photograph, the grain size of the specimen is _______________ for accurate intensity measurements with the diffractometer.
Answer: Too large
19.When the orientation of large numbers of crystals have to be determined in a routine manner, _____________ method is superior.
Answer: Diffractometer
20.If the crystal is bent or polygonized, the diffracted beam will broaden and the Laue spot will be a __________________ in shape.
Answer: Rectangular