Physics Of Metals In Metallurgy — Part 2 MCQs with Explanations

Burgers vector of the undissociated dislocation line is $$\frac{a}{2}\left[ {10\overline 1 } \right]$$ is the correct answer to “A dislocation line in a fcc crystal dissociates into two partials which have their Burger vectors as $$\frac{a}{6}\left[ {2\overline 1 \overline 1 } \right]$$ and $$\frac{a}{6}\left[ {11\overline 2 } \right],$$ Indicate the correct statement.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

1.807 is the correct answer to “In a single crystal of copper (lattice parameter 3.615°A). The distance between (11) planes (in °A) is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

P-1, Q-2, R-4, S-3 is the correct answer to “Match the following metals and alloys with their slip planes for room temperature deformations. P. Austenitic stainless steel 1. None Q. Molybednum 2. (110) R. Cadmium 3. (111) S. Tin 4. (0001)”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

m-2 and MPa.m$$^{\frac{1}{2}}$$ is the correct answer to “The respective units for dislocation density and stress intensity factor are”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

both A and B is the correct answer to “In a cubic lattice, the direction [123] is contained in the”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

2.54 is the correct answer to “Shear modulus of copper is 45 GPa. Lattice parameter of copper is 3.61°A. The magnitude of burgers vector in copper is . . . . . . . . °A.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

makes an angle of 30° with the normal to (111) plan is the correct answer to “The direction [011] in cubic crystals”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

1.15 is the correct answer to “For an FCC metal, the ratio of interplanar spacing obtained from the first two peaks of the X-ray diffraction pattern is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

Q, S is the correct answer to “Which of the following statements are true about edge dislocations? P. Edge dislocations do not have an extra half plane associated with them. Q. The Burger vectors is perpendicular to the direction. R. Edge dislocations can avoid obstacles by cross-slip. S. Depending on geometry, parallel edge dislocations of opposite signs can attract or repel one another.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

Grain boundary energy > Twin boundary energy > Surface energy is the correct answer to “Which of the following is true for metals”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

0.05 is the correct answer to “If the drift velocity of holes under a field gradient of 150 V/m is 7.5 m/s, their mobility (in SI units) is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

12.3° is the correct answer to “In a powder diffraction photograph of copper (fcc structure with a lattice parameter of 0.3608 nm) taken with a cu-ka radiation (γ = 0.154 nm), the Bragg angle for the first line is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

3.99 is the correct answer to “The lowest angle reflection in a powder diffraction experiment or an fcc metal using Cu-Ka radiation (y = 1.54°A) occured at an angle of 19°30'. The lattice parameter of the metal is . . . . . . . . °A.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

P-2, Q-4, R-3, S-1 is the correct answer to “Match the phenomenon with their specific effects on X-ray diffraction patterns P. Macroscopic residual stress 1. Additional diffraction lines Q. Microscopic residual stress 2. X-ray line shift R. Ordering reaction 3. Debye rings of non-uniform intensity S. Preferred orientation 4. X-ray line broadening”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

105 is the correct answer to “The largest size of immobilised segment of dislocation in a Frank Read (FR) source contained in a polycrystalline material is of the order of grain size. In a metal of 10 μm grain size, the shear stress required to operate such a FR source is 100 MPa. If the grain size in the same metal is reduced to 10 μm, the shear stress required to operate such FR source would be . . . . . . . . MPa.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

CO2+ is the correct answer to “The outer electron configurations of CO, Fe and Ni atoms are-respectively 3d 7 4s 2 , and 3d 2 , 3d 8 4s 2 . Which of the following ions has the potential to produce the highest magnetic moments”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

2.24 is the correct answer to “Silicon is doped with arsenic (concentration 10 20 atoms.m -3 ). At room temperature, the electron and hole mobilities in Si are 0.14 m 2 .v -1 .s -1 and 0.05 m 2 v -1 .s -1 respectively. The conductivity in (Ωm) -1 , at room temperature for Si doped with As is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

(110) is the correct answer to “In an X-Ray powder pattern of a simple cubic crystal, the 2 nd peak corresponds to”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

F is zero and U is minimum is the correct answer to “At equilibrium spacing in a crystalline solid, which of the following is true for net interatomic force (F) and potential energy (U)”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

1.633 is the correct answer to “In an ideal HCP packing, the c/a ratio is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

P-2, Q-1, R-3 is the correct answer to “Match each material in Group I with a bond type in Group II . Group I Group II P. Silicon 1. Metallic bonding Q. Copper 2. Covalant bonding R. Sodium chloride 3. Ionic bonding 4. Vander-Wallis bonding”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

$$\left( {11\overline 1 } \right)$$ is the correct answer to “Dissociation of a dislocation into two particals in an FCC metal is given by the following equation. $$\frac{a}{2}\left[ {1\overline 1 1} \right] \to \frac{a}{6}\left[ {2\overline 1 1} \right] + \frac{a}{6}\left[ {1\overline 2 \overline 1 } \right]$$ On which plane do these two partial dislocations lie”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

0.94 is the correct answer to “The density and associated crystallinity for two polypropylene samples are as follows: density, g/cm 3 crystallinity, % 1.20 50 1.44 80 Density of totally amorphous polypropylene is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

holes is the correct answer to “The majority charge carriers in p-type silicon are”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

0.25 is the correct answer to “An edge dislocation is present in α-Fe. Atomic diameter of iron atom is 0.25 nm and its shear modulus is 70 GPa. Modulus of the Burgers vector (in nm) is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

$$\frac{a}{2}\left[ {\overline 1 10} \right] + \frac{a}{2}\left[ {0\overline 1 \overline 1 } \right]$$ is the correct answer to “Which one of the following reactions is fcc/bcc crystals with lattice parameter 'a' is energetically favourable”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

54.7 is the correct answer to “For a simple cubic unit cell with unit vectors, i, j and k, the angle between the lattice vector [100] and [111] in degrees is”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

1.1 is the correct answer to “The electrical conductivity of pure silicon at 300 K is 4.34 × 10 -4 (Ωm) -1 and at 500 K, it is 2.15(ΩM) -1 . Given that the Boltzman constant, R = 8.6 × 10 -5 eV .K -1 , the band energy gap is . . . . . . . . eV.”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.

0.4 nm is the correct answer to “A peak in the X-ray diffraction pattern is observed at 2θ = 78°, corresponding to [311] planes of an fcc metal, when the incident beam has a wavelength of 0.154 nm. The lattice parameter of the metal is approximately”. This question is standard in competitive examination syllabi for Physics Of Metals In Metallurgy.