X-Ray Spectrometers Multiple Choice Questions and Answers
X-Ray Spectrometers Multiple Choice Questions and Answers
1. The crystal used as X-ray grating has _______ dimensional lattice arrays.
a) One
b) Two
c) Three
d) Four
Answer: Three.
2. X-ray diffractometers provide ____________ information about the compounds present in a solid sample.
a) Quantitative
b) Qualitative
c) Quantitative and qualitative
d) Either quantitative or qualitative
Answer: Quantitative and qualitative
3. X-ray emission must be analysed against a background of _______ radiation.
a) Blue
b) Yellow
c) White
d) Green
Answer: White.
4. In Diffractometer, the identification of a component of the sample from its powder diffraction pattern is based upon the _________ of lines and their relative ___________
a) Number, length
b) Number, intensity
c) Position, length
d) Position, intensity
Answer: Position, intensity.
5. In Diffractometers, line intensities depend on ______ and kind of atomic reflection centres in each set of plates.
a) Number
b) Position
c) Length
d) Distance between lines
Answer: Number.
6. Absorption meter is __________ and ____________ of the chemical state of the element concerned.
a) Non-destructive, independent
b) Destructive, independent
c) Non-destructive, dependent
d) Destructive, dependent
Answer: Non-destructive, independent.
7. The measurement of intensity of fluorescent X-rays provide a simple and ____________ way of _____________ analysis.
a) Destructive, quantitative
b) Non-destructive, quantitative
c) Destructive, qualitative
d) Non-destructive, qualitative
Answer: Non-destructive, quantitative.
8. In total reflection X-ray fluorescence spectrometer, the specimen is excited by the primary X-ray beam at a grazing angle _______ the critical angle.
a) Greater than
b) Less than
c) Equal to
d) Which is a complement of
Answer: Less than.
9. The energy of the emitted X-rays depends upon the _________ of the atom and their intensity depends upon the __________
a) Atomic number, amount of sample
b) Mass number, amount of sample
c) Mass number, concentration of atoms
d) Atomic number, concentration of atoms
Answer: Atomic number, concentration of atoms.
10. Which of the following components make use of a thin metal foil to isolate a nearly mono-energetic excitation beam?
a) Transmission-anode X-ray tube
b) Secondary fluorescence target
c) Slit
d) Filters
Answer: Filters.
11. In Energy dispersive system, the energy level and the number of pulses is related to which of the following?
a) Amount of sample, element involved
b) Element involved, concentration of the element
c) Concentration of the element, element involved
d) Number of atoms, amount of sample
Answer: Element involved, concentration of the element.
12. Which of the following can be done to avoid loss of intensities of X-rays due to the absorption of long wavelength X-rays?
a) Apparatus must be contained in a chamber
b) Air in the chamber must be replaced by helium
c) Inert gas atmosphere must be provided
d) Proper slits must be used
Answer: Air in the chamber must be replaced by helium.
13. Why is a mono-energetic radiation source required in X-ray fluorescent spectrometer?
a) To provide good sensitivity
b) To provide high accuracy
c) To provide a proper range
d) To reduce unwanted background
Answer: To reduce unwanted background.
14. Energy dispersive system uses which of the following detectors?
a) Optical detector
b) Semiconductor detector
c) Thermistor
d) Bolometer
Answer: Semiconductor detector.
15. Which of the following does not make the X-ray tube nearly monochromatic?
a) Transmission-anode X-ray tube
b) Secondary fluorescence target
c) Slit
d) Filters
Answer: Slit.
16. Which of the following is the disadvantage of silicon semiconductor detector?
a) Low stable
b) Can be operated only at low temperatures
c) Have low count-rate
d) Low resolution
Answer: Can be operated only at low temperatures
17. Which of the following components of the X-ray fluorescent spectrometer induces fluorescent radiation?
a) Excitation source
b) Energy analyser
c) X-ray spectrometer
d) Detection System
Answer: Excitation source.
18. Prompt emission of X-ray by an atom ionised by a higher energy X-ray is a type of which of the following phenomena?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: Fluorescence.
19. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a long or a short time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: Luminescence.
20. Which of the following is Mosely’s equation if ‘C’ is the speed of light, ‘a’ is proportionality constant, ‘σ’ is a constant which depends on electronic transition series, ‘Z’ is the atomic number and ‘λ’ is the wavelength?
a) Cλ= a(Z-σ)/^2
b) C/λ= a(Z-σ)^2
c) C(Z-σ)2= aλ
d) C(Z-σ)2= a/λ
Answer: C/λ= a(Z-σ)^2.
21. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a long time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: Phosphorescence.
22. If the absorption of electromagnetic radiation by matter results in the emission of radiation of the same or longer wavelengths for a short time, the phenomenon is termed as which of the following?
a) Luminescence
b) Fluorescence
c) Phosphorescence
d) Spontaneous emission
Answer: Fluorescence.
23. In X-ray fluorescence spectrometer, the relationship between the excitation intensity and the intensity of fluorescence does not depend on which of the following?
a) Spectrum of the incident radiation
b) Angle of radiance
c) Molecular weight
d) Incident angle
Answer: Incident angle.
24. In absorption meter, the change in thickness of aluminium required for different samples is a function of the difference in which of the following parameters?
a) Amount
b) Concentration
c) Colour
d) Composition
Answer: Composition.
25. In absorption meter, the two halves of the X-ray beam are allowed to fall on which of the following components?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator
Answer: Photomultiplier tube.
26. X-ray absorption meters have which of the following major disadvantages?
a) Low accuracy
b) Low range
c) Low sensitivity
d) It is destructive
Answer: Low sensitivity.
27. In absorption meter, which of the following is placed between the chopper and the reference cell?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator
Answer: Attenuator.
28. In absorption meter, which of the following is placed between the cell and the X-ray tube?
a) Collimator
b) Filter
c) Chopper
d) Attenuator
Answer: Chopper.
29. The photomultiplier tube used is absorption meter is coated with which of the following materials?
a) Sodium
b) Potassium
c) Phosphorous
d) Chlorine
Answer: Phosphorous.
30. In absorption meter, which of the following is adjusted until the absorption of two X-ray beams are brought into balance?
a) Collimator
b) Filter
c) Photomultiplier tube
d) Attenuator
Answer: Attenuator.
31. Which of the following is the most common instrument for photographic recording of diffraction patterns?
a) Debye-Scherrer powder camera
b) Gamma camera
c) Geiger tube
d) Scintillation counter
Answer: Debye-Scherrer powder camera.
32. Diffractometers are similar to which of the following?
a) Optical grating spectrometer
b) Prism spectrometer
c) Photo multiplier
d) Photovoltaic cell
Answer: Optical grating spectrometer.
33. In powder diffractometer, the sharpness of the lines is greatly determined by which of the following?
a) Quality of the sample, size of the slit
b) Quality of the slit, size of the sample
c) Thickness of the slit, amount of the sample
d) Number of slits, composition of the sample
Answer: Quality of the slit, size of the sample
34. In powder method, the powder sample is contained in which of the following?
a) Thin walled glass capillary tubes
b) Thin walled test tube
c) Thin walled curvettes
d) Thin walled flask
Answer: Thin walled glass capillary tubes.
35. X-ray diffractometers are not used to identify the physical properties of which of the following?
a) Metals
b) Liquids
c) Polymeric materials
d) Solids
Answer: Liquids.
36. With the help of which of the following equations is the distance calculated from a known wavelength of the source and measured angle?
a) Coolidge equation
b) Bragg’s equation
c) Debye equation
d) Scherrer equation
Answer: Bragg’s equation.
37. Using the powder method of diffractometers, which of the following can be determined?
a) Percentage of K+
b) Percentage of Na+ and Cl-
c) Percentage of KBr and NaCl
d) Percentage of Br-
Answer: Percentage of KBr and NaCl.
38. Which of the following components are used as the sample carrier?
a) Curvette
b) Flask
c) Capillary tube
d) Float glass
Answer: Float glass.
39. The major problem associated with sample preparation is which of the following?
a) Preparing sample in the right quantity
b) Choosing sample holders
c) Matrix effects
d) Reflection by holders
Answer: Matrix effects.
41. The x-ray beam produced by the primary x-ray tube passes through which of the following components to produce the incident radiation?
a) Detector
b) Slit-collimator arrangement
c) Sample reflector
d) Monochromator
Answer: Slit-collimator arrangement.
42. Which of the following happens when a large solid angle is intercepted as the detector is placed close to the sample?
a) Maximum efficiency increases
b) Maximum efficiency decreases
c) Efficiency is not affected
d) Process response becomes fast
Answer: Maximum efficiency increases.
43. To monitor the primary beam, which of the following is used?
a) Scintillation counter
b) GM counter
c) Gamma counter
d) Proportional counter
Answer: GM counter.
44. In computer-controlled corrective iteration method, which of the following is used to estimate absorption corrections?
a) Initial raw intensity data
b) Elemental composition
c) Amount of sample
d) Amount of radiation
Answer: Initial raw intensity data.
45. Which of the following devices are used as a detector?
a) Thermistor
b) Optical detector
c) Solid state detector
d) Golay cell
Answer: Solid state detector.
46. Which of the following crystals are polished to act as the cut-off reflector?
a) Quartz
b) Beryllium
c) Silicon
d) Lithium
Answer: Silicon.
47. The suppression of high energy bremsstrahlung radiation improves which of the following?
a) Signal to background ratio
b) Accuracy
c) Sensitivity
d) Coherence
Answer: Signal to background ratio.
48. The alternative method using laser does not analyse vapours by which of the following methods?
a) Mass spectrometer
b) Optical emission
c) Absorption photometry
d) X-ray photometry
Answer: X-ray photometry
49. Using which of the following components is the generated x-rays focussed upon the specimen?
a) X-ray tube
b) Monochromator
c) Collimator
d) Detector
Answer: Collimator.
50. The electron optics consists of an electron gun followed by which of the following components?
a) Collimator
b) Slit
c) Amplifier
d) Electron beam probe
Answer: Electron beam probe.
51. Which of the following is the limit of detectability of electron microprobe analyser?
a) 10-14 g
b) 10-140 g
c) 10-7 g
d) 10-70 g
Answer: 10-14 g.
52. The specimen is mounted inside which of the following components?
a) Test tube
b) Glass capillary tube
c) Vacuum column
d) Curvette
Answer: Vacuum column.
53. Which of the following is not a type of optics employed in electron probe microanalyser?
a) Electron optics
b) Light optics
c) X-ray optics
d) Gamma optics
Answer: Gamma optics.
54. The electrons are accelerated by voltages in which of the following ranges?
a) 5 and 50kV
b) 50 and 500kV
c) 500 and 5000kV
d) 25 and 250kV
Answer: 5 and 50kV.
55. How can the resolution of the collimator be increased?
a) By reducing the separation between the metal plates of the collimator
b) By increasing the separation between the metal plates of the collimator
c) By increasing the number of metal plates
d) By decreasing the number of metal plates
Answer: By reducing the separation between the metal plates of the collimator.
56. Which of the following is the effective resolution limit in electron probe microanalyser?
a) 1mm
b) 10mm
c) 100mm
d) 1000mm
Answer: 1mm.
57. The x-rays generated come out of the Coolidge tube through which of the following?
a) Beryllium window
b) Tungsten window
c) Collimator
d) Target material
Answer: Beryllium window.
58. In X-ray spectrometers, the specimen or the sample is placed after which of the following components?
a) X-ray tube
b) Monochromator
c) Collimator
d) Detector
Answer: X-ray tube.
59. When x-rays emitted from molybdenum are allowed to pass through a zirconium filter, which of the following occurs?
a) It absorbs radiation of shorter wavelength
b) It absorbs radiation of longer wavelength
c) It allows radiation of shorter wavelength to pass through
d) It allows radiation in a particular band to pass through
Answer: It absorbs radiation of longer wavelength.
60. Which of the following components are used to generate X-rays?
a) Meyer tube
b) West tube
c) Anger tube
d) Coolidge tube
Answer: Coolidge tube.
61. Which of the following crystals are not suited for x-ray grating?
a) Topaz
b) Lithium fluoride
c) Calcium fluoride
d) Sodium fluoride
Answer: Sodium fluoride.
62. Which of the following is not a target metal used in the Coolidge tube?
a) Rhodium
b) Cobalt
c) Gold
d) Silver
Answer: Gold.
63. The cathode in the Coolidge tube is made of which of the following elements?
a) Quartz
b) Iron
c) Tungsten
d) Barium
Answer: Tungsten.
64. Fluorescent X-ray spectrometers would require only moderate-intensity X-ray tubes.
a) True
b) False
Answer: False.
65. Absorption meters cannot be used to detect broken bones.
a) True
b) False
Answer: False.
66. The applications of X-ray absorption meters are limited when compared with X-ray emission procedures.
a) True
b) False
Answer: True.
67. When compared to filters, monochromators provide much signal to noise ratio.
a) True
b) False
Answer: True.
68. The cathode in the Coolidge tube is kept in an inclined manner.
a) True
b) False
Answer: False.
69. In Diffractometers, the intensities of the diffraction peaks of a given compound in a mixture are proportional to the fraction of the material in the mixture.
a) True
b) False
Answer: True.
70. When certain geometric requirements are met, X-rays scattered from a crystalline solid can constructively interfere with each other and produce a diffracted beam.
a) True
b) False
Answer: True.
71. Computer-controlled corrective iteration is the only reliable method of matrix effects correction.
a) True
b) False
Answer: True.
72. Electron probe microanalyser is a method of destructive elemental analysis.
a) True
b) False
Answer: True.
73. In curved crystal arrangement, angular velocity of the crystal is twice that of the detector.
a) True
b) False
Answer: False.
74. Total reflection X-ray fluorescence spectrometer is attractive for elements which lack reliable wet chemical methods.
a) True
b) False
Answer: True
75. The problem of spectral interference is not severe in X-ray spectroscopy.
a) True
b) False
Answer: True.
76. Micro probe analyser cannot be used on inhomogeneous material.
a) True
b) False
Answer: False.
77. The analysis of X-ray beam by diffraction is similar to spectrum analysis carried out with a diffraction grating.
a) True
b) False
Answer: True.
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