7/28/2019 1-3 X-Ray Sample Questions 2013

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Dr. Saad B. H. Farid X-Ray Characterization of Materials 1 |/ /

Sample Questions 2013

1- Draw a schematic of typical X-ray spectrum, show the function of the properly selected -filter material2- State the average formula. Explain the modern filtration techniques for K X-rays.3- Tabulate the cubic, tetragonal and hexagonal crystal systems with their axial lengths and angles formulas

for their plane spacing

4- What is the "Max von Laue" experiment has been proved?5- State some possible applications of Laue diffraction6- State Bragg's law with detailed illustration7- What are the Systematic absences? Tabulate them for P, I and F lattices8- What is the reciprocal lattice?9- The set of points shown on X-ray photographs, e.g. Laue photographs; what is it called?10- Connect the real lattice with the reciprocal lattice with the necessary relations. (all in page 6 except that ford*2)11-Draw a sketch illustrating the difference between Lorentz and Gaussian distribution, mark FWHM and state

what kind of distribution is expected for X-ray diffraction peak.12-Why the formula (B=0.9/t cos) is problematic in determination of powder particle size? What it is

actually measures? Use a sketch.

13-Why the formula (B=0.9/t cos) always gives erratically nano estimates for micro-sizes powders? Whatcan be done to improve the results?

14-A Cu K1 (1=1.5406) X-ray diffractogram for a certain crystalline compound consist of a multiple ofdiffraction peaks. The last peak position was at 2=141.2. The same experiment is repeated with Mo target

(1=0.7093); what is the new pattern looks like? Where is the new last peak position mentioned above?

15-How can qualitative XRD analysis are done based on ASTM or JCPDS data?16-Why the relation between the intensity and concentration is not linear in X-ray powder diffraction?17-Describe briefly the main methodologies of XRD quantitative analysis18-A powder mixture contains unknown Xa, Xb, Xc...etc. According to the method of standard addition; the

following Ia,hkl/Ib,hkl'versus Yaadditions Data is obtained (0%,0.7), (5%,1.0), (10%,1.8), (15%, 2.2),

(20%,3.0). Find graphically an estimation of the unknown content Xa.

19-Following the method of Internal standard to find the unknown Xaconcentration of phase a; severaldiffractograms are obtained for different additions Ybof the internal standard. The (Yb%, Ia,hkl/Ib,hkl')

table is as follows (2%,0.6), (5%,0.8), (10%,1.3), (15%,1.5), (20%,2.0). Get graphically the best estimation

of the unknown Xaphase concentration.20-Draw a Sketch for Fluorescent X-ray spectroscopy setup. Why it is necessary to find other lines than K to

ascertain the determination of an element?

21-Compare Optical spectroscopy versus X-ray Fluorescent analysis (in terms of the excited electrons andphoton energies).

22-What are the two tables that required for qualitative X-ray Fluorescent analysis? Which of them should bereplaced when the analyzing crystal is replaced?

23-Select a proper sample for the preliminary investigation for X-ray Fluorescent analysis and sate why.24-Describe the Matrix Effect in X-ray Fluorescence Analysis? What is the figure (in page 25) means to you?25-Describe specimen preparation for X-ray Analysis.26-Describe WDS in X-ray Analysis.27-Describe EDS in X-ray Analysis and explain why it is preferable on WDS.

GD LUCK