Physics of Metals in Metallurgy MCQ Questions and Answers | Metallurgical Engineering Page-7 section-1

61.
In an ideal HCP packing, the c/a ratio is

A. 1.225

B. 1.414

C. 1.633

D. 1.732

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62.
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

A. P-2, Q-1, R-4

B. P-1, Q-3, R-1

C. P-4, Q-1, R-3

D. P-2, Q-1, R-3

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63.
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?

A. $$\overline 1 11$$

B. -111

C. $$\left( {1\overline 1 1} \right)$$

D. $$\left( {11\overline 1 } \right)$$

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64.
The density and associated crystallinity for two polypropylene samples are as follows:

density, g/cm³ crystallinity, %

1.20 50

1.44 80

Density of totally amorphous polypropylene is

A. 0.64

B. 0.74

C. 0.84

D. 0.94

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65.
The majority charge carriers in p-type silicon are

A. Free electrons

B. ions

C. conduction electrons

D. holes

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66.
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

A. 0.125

B. 0.25

C. 0.5

D. 0.625

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67.
Which one of the following reactions is fcc/bcc crystals with lattice parameter 'a' is energetically favourable?

A. $$\frac{a}{2}\left[ {\overline 1 10} \right] + \frac{a}{2}\left[ {0\overline 1 \overline 1 } \right]$$

B. $$\frac{a}{2}\left[ {111} \right] + \frac{a}{2}\left[ {11\overline 1 } \right]$$

C. $$\frac{a}{2}\left[ {111} \right] + \frac{a}{2}\left[ {11\overline 1 } \right]$$

D. $$\frac{a}{2}\left[ {111} \right] + \frac{a}{2}\left[ {111} \right]$$

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68.
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

A. 35.2

B. 54.7

C. 60

D. 90

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69.
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.

A. 0.65

B. 1.1

C. 1.5

D. 2.2

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70.
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

A. 0.6 nm

B. 0.4 nm

C. 0.3 nm

D. 0.2 nm

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Group I	Group II
P. Silicon	1. Metallic bonding
Q. Copper	2. Covalant bonding
R. Sodium chloride	3. Ionic bonding
	4. Vander-Wallis bonding

Physics of Metals in Metallurgy MCQ Questions and Answers | Metallurgical Engineering

61. In an ideal HCP packing, the c/a ratio is

Answer & Solution

62. 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

Answer & Solution

Answer & Solution

64. The density and associated crystallinity for two polypropylene samples are as follows: density, g/cm3 crystallinity, % 1.20 50 1.44 80 Density of totally amorphous polypropylene is

Answer & Solution

65. The majority charge carriers in p-type silicon are

Answer & Solution

66. 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

Answer & Solution

67. Which one of the following reactions is fcc/bcc crystals with lattice parameter 'a' is energetically favourable?

Answer & Solution

68. 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

Answer & Solution

69. 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.

Answer & Solution

70. 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

Answer & Solution

61.
In an ideal HCP packing, the c/a ratio is

62.
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

64.
The density and associated crystallinity for two polypropylene samples are as follows:

density, g/cm³ crystallinity, %

1.20 50

1.44 80

Density of totally amorphous polypropylene is

65.
The majority charge carriers in p-type silicon are

66.
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

67.
Which one of the following reactions is fcc/bcc crystals with lattice parameter 'a' is energetically favourable?

68.
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

69.
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.

70.
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