Solid State Chemistry Questions and Answers – Modern X-Ray Powder Techniques and their Applications


This set of Solid State Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Modern X-Ray Powder Techniques and their Applications”.

1. A powder diffractometer is an___________
a) Electron density instrument
b) Powder electron refraction instrument
c) X-ray spectrum detector instrument
d) Powder X-ray instrument.
View Answer

Answer: d
Explanation: The most commonly used powder X-ray instrument is the powder diffractometer. It has a proportional, scintillation or Geiger counter as the detector which is connected to a chart recorder or sometimes to a means of digital output.

2. In the powder diffractometer, the counter is set, the counter is set to scan at a ________
a) Variable temperature
b) Constant temperature
c) Constant angular velocity
d) Variable angular velocity
View Answer

Answer: c
Explanation: In normal use, the counter in the powder diffractometer is set to scam over a range of 2Θ values at a constant angular velocity, it is common practice to refer to the angle 2Θ between the diffracted and undiffracted beams, rather than to the Bragg angle, Θ.

3. The intensities in the powder diffractometer is taken as________
a) very low height
b) peak height
c) constant height
d) variable height
View Answer

Answer: b
Explanation: In the powder diffractometer, the intensities are taken as peak height, unless very accurate work is being done, in which case areas may be measured, the most intense peak is given the intensity of 100 and the rest are scaled accordingly.

4. In the powder diffractometer, a correction factor varies with which of the following factors?
a) Temperature
b) Solubility
c) Concentration
d) Angle 2Θ
View Answer

Answer: d
Explanation: A correction factor in the powder diffractometer varies with 2Θ, is obtained from the discrepancy between observed and the true d-spacings of the standard and is then applied to the pattern that is being measured.

5. Which of the following phenomenon takes place when the arrangement of the crystal is not random?
a) The temperature increases
b) The temperature decreases
c) Preferred orientation exits
d) Preferred orientation enters
View Answer

Answer: c
Explanation: If the crystal arrangement is not random, then preferred orientation exists and can introduce errors, sometimes very large, into the measured intensities preferred orientation is a serious problem for the materials that crystallize in a characteristic, very non-spherical shape like clay minerals, etc.

6. Which one of the following is the big disadvantage of the Debye-Scherrer cameras?
a) High intensity diffracted beams
b) High intensity refracted beams
c) Low intensity refracted beams
d) Divergent diffracted beams
View Answer

Answer: d
Explanation: The big disadvantage of early Debye-Scherrer cameras is that incident and diffracted beams are inevitable, somewhat divergent and of low intensity. In diffractometer and the modern focusing cameras, a convergent X-ray beam is used.

7. Using the convergent X-ray in powder diffractometer which of the following factor is affected?
a) Temperature
b) Reflection
c) Resolution
d) Concentration
View Answer

Answer: c
Explanation: In diffractometer and the modern focusing cameras, a convergent X-ray beam is used, this gives a dramatic improvement in resolution and because much more intense beams may be used, exposure time ate greatly reduced.

8. Which one of the following is an additional feature of the focusing cameras?
a) X-ray
b) Crystal monochromator
c) Gamma rays detector
d) Electron stopper
View Answer

Answer: b
Explanation: In the focusing cameras an additional feature is the crystal monochromator which serves two functions, to give highly monochromatic radiation and to produce an intense, convergent X-ray beam.

9. A crystal monochromator contains which of the following material?
a) X-ray beam detector
b) A very small crystal
c) Crystal electrode
d) Large single crystal
View Answer

Answer: d
Explanation: A crystal monochromator consists of a large single crystal of for example quartz oriented such that one set of planes which diffracts strongly for quartz is at the Bragg angle to the incident beam.

10. For the accurate measurement of the d-spacings which of the following method is best to use?
a) Stockbarger method
b) Refractometry method
c) Diffractometry method
d) Dalton method
View Answer

Answer: b
Explanation: In order to measure the d-spacings accurately, Diffractometry is normally regarded as the best method and most of the patterns in the powder diffraction file gave been obtained by the Diffractometry. An internal standard of accurately known d-spacings must be added to the sample in order to eliminate the instrumental error.

Sanfoundry Global Education & Learning Series – Solid State Chemistry.

To practice all areas of Solid State Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.



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Solid State Chemistry Questions and Answers – Effect of Stress on a Powder Pattern


This set of Solid State Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Effect of Stress on a Powder Pattern”.

1. Crystals experience anomalous powder patterns under___________
a) Strain
b) Change in temperature
c) Change in concentration
d) Stress
View Answer

Answer: d
Explanation: Crystals exhibit anomalous powder patterns when they are under stress. Two types of stress can be applied one uniform compressive stress another non-uniform stress. Stress is force acted upon on a crystal per unit area of the crystal.

2. Contraction of the unit cell in the crystal occurs during which of the following phenomenon?
a) Uniform strain is applied
b) Uniform stress is applied
c) Non uniform stress is applied
d) Non uniform strain is applied
View Answer

Answer: b
Explanation: The whole powder pattern of the crystal may be shifted to lower d-spacings if the crystals are under a uniform compressive stress such that a contraction of unit cell occurs inside the crystal.

3. The powdered line are broadened in the crystal during which of the following phenomenon?
a) Uniform strain is applied
b) Uniform stress is applied
c) Non uniform stress is applied
d) Non uniform strain is applied
View Answer

Answer: c
Explanation: When a non uniform stress is applied to the crystal, different crystals or different parts of the same crystal may be deformed to differing degrees and the powder lines become broadened.

4. Stress is caused on the crystal by which of the following factor?
a) External strain applied
b) Internal stress
c) External pressure
d) External change in temperature
View Answer

Answer: c
Explanation: Stresses on the crystal is caused by the application of an external pressure for example the working hard of the metals in which residual distortions are present in the crystal after treatment.

5. Chemical reaction inside the crystal can cause________
a) Change in external temperature
b) Change in concentration
c) Stress
d) Change in solubility
View Answer

Answer: c
Explanation: Stress in the crystal can be generated internally as a consequence of a chemical reaction taking place inside the crystals, for example coherent precipitation of supersaturated solid solutions, age hardening of metals and ceramics etc.

6. Stress is caused or generated internally by the consequence of chemical reaction taking place in the crystal, one of its example is occurrence of phase transitions during __________
a) Change in concentration
b) Change in solubility
c) Change in force
d) Change in temperature
View Answer

Answer: d
Explanation: Phase transition occurs I the crystals during cooling (if there is a change in the volume or shape of the crystals and they are embedded in a solid matrix, then the rigid environment of the matrix may prevent the transition from occurring to completion).

7. Unit cell parameters are determined by which of the following parameters?
a) Double crystal X-ray photographs
b) Single crystal X-ray photographs
c) Double crystal Gamma rays graphs
d) Single crystal Gamma rays graphs
View Answer

Answer: b
Explanation: The unit cell parameters in the crystal are often determined with the aid of single crystal X-ray photographs. The symmetry or unit cell type is first obtained from an inspection of the photographs.

8. What are the limitations for the accuracy of the values for the unit cell parameters?
a) Lack of sufficient temperature
b) Insufficient amount of the unit cells
c) Shrinkage of film
d) Lack of external pressure
View Answer

Answer: c
Explanation: There are several intrinsic limitations to the accuracy of the values thus obtained-lack of the internal standard, shrinkage of film, etc. And the accuracy of axial parameters is usually to between 0.05 and 0.2 percent.

9. Accurate cell parameters can be obtained from a least squares refinement of the _______________
a) S-spacings
b) Vacant p shells
c) d-spacings
d) vacant f shells
View Answer

Answer: c
Explanation: Accurate cell parameters may be obtained from a least squares refinement on the d-spacings of at least several high angle powder lines whose indexing is known for certain.

10. The intensities of various candidate reflections estimated qualitatively from the indexed single crystal photographs and the strongest of these almost certainly correspond to the reflection that gives___________
a) powder line
b) curve
c) stress
d) strain
View Answer

Answer: a
Explanation: The strongest of the various candidate reflections corresponds to the reflection that gives the powder line that is because spots that are weak on single crystal photographs are not usually observed in powder photographs unless the latter are grossly overexposed.

Sanfoundry Global Education & Learning Series – Solid State Chemistry.

To practice all areas of Solid State Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.



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Materials Science Questions and Answers – Fractures in Ceramics


This set of Materials Science Multiple Choice Questions & Answers (MCQs) focuses on “Fractures in Ceramics”.

1. Which of the point is there in a stress strain curve for a ceramic?
a) Ultimate tensile strength
b) Fracture point
c) Limit of proportionality
d) Yield point
View Answer

Answer: b
Explanation: The correct answer is fracture point. Unlike metals or non metals, ceramics just break which is reach the fracture point after a certain amount of strain.

2. Which of the following is correct
a) Aluminum oxide reaches fracture point before glass
b) Aluminum oxide reaches fracture point after glass
c) Aluminum oxide reaches fracture point at the same time as glass
d) They do not reach a fracture point
View Answer

Answer: a
Explanation: Aluminum oxide reaches fracture point before glass. In aluminum oxide for a large amount of stress little strain is produced.

3. Which of the following is a flexural strength not dependent on?
a) Force
b) Distance between supports
c) Specimen width
d) Length of specimen
View Answer

Answer: d
Explanation: Flexural strength is dependent on the force applied on the specimen, distance between the supports, width of the specimen and the height of the specimen and hence it does not depend on the length of the specimen.

4. For edge flaws to occur which of the following should be the value of constant in stress intensity factor formula?
a) 1.1
b) 1.2
c) 1.02
d) 1.12
View Answer

Answer: d
Explanation: The correct answer is 1.12. For an edge flaw to occur, the value of the constant in the stress intensity factor formula should be 1.12.

5. Which of the following can be the tensile strength of fused silica (SiO2)?
a) 110 MPa
b) 150 Mpa
c) 90 MPa
d) 80 MPa
View Answer

Answer: a
Explanation: The range for the tensile strength of fused silica (SiO2) which is a ceramic is 110 MPa. Therefore only 110 Mpa is the correct answer.

6. For zircon for the same flaw size, the intensity factor is more than alumina.
a) True
b) False
View Answer

Answer: a
Explanation: The above statement is true. For a given flaw size for example 50 micrometers, the intensity factor for zircon is 4.6 units and that of alumina is 3.7 units.

7. The largest constituent elements and flaws increase the flexural strength.
a) True
b) False
View Answer

Answer: b
Explanation: The above statement is false. The smallest constituent element and flaws increase the flexural strength.

8. Which of the following shows the best fracture strength?
a) Zircon
b) Macor
c) Alumina
d) There fracture strength are not comparable
View Answer

Answer: a
Explanation: Zircon shows the best fracture strength among the three elements, alumina, zircon and macor.

Sanfoundry Global Education & Learning Series – Materials Science.

To practice all areas of Materials Science, here is complete set of 1000+ Multiple Choice Questions and Answers.



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