Regional Maritime University

1 . the following is true about a unit cell and a crystal.

Multiples of crystals arranged in long order is a unit cell
Multiples of atoms arranged in unit cell form unit cell
Unit cell exhibit multiple crystal structure.
multiples of umit cells arranged in long order form crystal

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2 . Which of these best describe a unit cell

Simplest 3 dimensional arrangement of an atom
Building block of atoms
Simplest 3 dimensional arrangement of atoms
Simplest atom in 3 dimensional arrangement

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3 . The volume of the FCC unit cell is

(16R^3)/?3
(16R^3)/?2
(64R^3)/(?3)
(16R^3)?2

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4 . Find the atomic packing factor (APF) for FCC

0.68
0.74
52%
74%

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5 . Calculate the volume percentage change as iron transform from bcc to FCC if the atomic radii are 1.240A and 1.270A respectively

-1.26
46.2
1.26
2.86A

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6 . Find the index of a plane that intercepts the three axes at unit cell distant 1, 1 and ½ a)

(1,1,2)
(1,2,2)
(1 1 2)
(2 1 1)

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7 . The valency of calcium of atomic number 20 is

4s
S2
2
3d

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8 . Which of these statement is false

In covalent bonding there is sharing of electrons
In ionic bonding there is donation of electrons and electrostatic attraction
in metallic bonding there is presence of electron cloud
Covalent bond is always between metals and non-metals

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9 . If the molar mass for Iron(Fe) carbon is 55.845 g/mole . Find the weight of its unit cell if it has Fcc structure

9.7213e -23
37.11 × 10e-23
1.6 x 10e-19
13.85

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10 . If for a certain BCC crystal, the (110) plane has a separation of 1.181A and wavelength of X-ray is 1.540A. The glance angle for the 1st line of reflection and the atomic radius will be

21.50 , 1.67A
40.50, 1.67A
400, 1.34A
20.50, 1.34A

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11 . Bragg’s law is not a sufficient condition for diffraction by crystalline solids.

TRUE
FALSE

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12 . Which of these have a Crystal structure not common to metals

Hexagonal closed packed ,body centred cubic
Body centred cubic, orthorhombic crystal
Face centred cubic, body centred cubic
Face centred cubic, hexagonal closed packed.

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13 . X-ray diffraction patterns are used for studying crystal structure of solids because

They have very high energy, hence they can penetrate through solids
They are electromagnetic radiation, and hence do not interact with matter (crystals)
Their wavelengths are comparable to inter-atomic distances
Their high frequency enables rapid analysis

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14 . Which of the following lattices has the highest void fraction?

face centered cubic
body centered cubic unit cell
simple cubic
Hexagonal closed packed

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15 . Graphite is a common allotrope of Carbon. Its crystal structure is:

Cubic
Monoclinic
Orthorhombic
Hexagonal

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16 . In which of the following Bravais lattices none of the sides are equal?

triclinic
orthorhombic
monoclinic
all the above

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17 . Coordination number for an ideal BCC metallic crystal is:

12
6
8
16

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18 . n which of the following Bravais lattices, not all axial angles are right angles?

Tetragonal
Rhombohedral
Orthorhombic
Cubic

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19 . Which of the following Bravais lattices exist as face centered unit cell?

Orthorhombic
monoclinic
tetrahedral
non of the mentioned

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20 . Most Bravais lattices are of the type:

Primitive unit cell
Body centered unit cell
face centered unit cell
end centered unit cell

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21 . Grain boundaries are one of the causes of corrosion of metals?

TRUE
FALSE

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22 . The smallest portion of a crystal which when repeated in different directions generates the entire crystal is called

Lattice points
Crystal lattice
Unit cell
None of the mentioned

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23 . HCP and BCC are called close-packed structures. Close packed structures have:

Highest void fraction
Highest density
Highest packing efficiency
All of the mentioned

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24 . Packing efficiency of a crystal structure is the ratio of:

Volume occupied by particles to the total volume of the unit cell
Volume occupied by particles to that by voids
Total volume of the unit cell to the volume occupied by particles
Volume occupied by voids to that by particles

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25 . Co-ordination number of a crystalline solid is:

Number of particles in the unit cel
Number of nearest neighbours of a particle
Number of octahedral voids in a unit cell
Number of tetrahedral voids in a unit cell

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26 . Allotropes differ in which of the following properties:

Atomic Number
mass number
crystal structure
electrongativity

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27 . How many periods are there in a modern periodic table?

5
6
7
8

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28 . Which if the following is not an SI unit?

Kilogram
Mole
Atomic Mass Unit
Coulomb

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29 . Elements in the same column of the periodic table have

Similar valence shell electron configuration
Same value of highest principal quantum number
Same number of nucleons
All of the mentioned

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30 . Which of the following is not a pure form of matter?

element
compund
solution
both compound and solution

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31 . Which of the following has the least number of atoms?

One gram of Hydrogen gas
One gram of Helium gas
One gram-mole of Oxygen gas
one gram of chlorine gas

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32 . Atomic number of a species is the number of:

Neutrons
Protons
valence electrons
nuceus

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33 . A first solid phase results in a second solid phase another third solid phase on cooling during __________ reaction.

Eutectoid
Eutectic
hypoeutectoid
peritectic

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34 . The phase above eutectoid temperature for 0.8%carbon steels is known as _______

cementite
ferrite
pearlite
austenite

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35 . What is the eutectoid structure of Iron?

0.8%Fe
Pearlite
Gamma Fe
Ferrite

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36 . What is the maximum %C by weight in hypo-eutectoid steels?

0.50%
0.70%
0.80%
1.20%

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37 . For a FCC lattice structure a=

4R/?3
4R/(?2)
?2/4R
?3/4R

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38 . The electronic configuration of Calcium of atomic number 20 is:

1s^2 2s^2 3s^2 3p^6 3d^2
1s^2 2s^2 3s^2 3p^5
1s^2 2s^2 3s^2 3p^6 3d^(2 ) 4s^2
1s^2 2s^2 3s^2 3p^6 4s^2

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39 . For a BCC lattice atomic packing factor is

52%.
0.68
0.74
68%

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40 . State Bragg’s law

M = 2dsin?
Sin? = ? hkl
n? = 2d(hkl) sin?
? = dhklsin?/2

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41 . If the first line diffraction for the d111 of copper of an FCC crystalline structure is 43degrees. What is the lattice constant a, of copper if the wavelength of the x-rays used is 1.54A

1.2A
1.12A
1.9A
3.6A

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42 . Multiple crystal structures of an element is referred to us

Polymorphism
Allotropy
Polymorphs
Lattice

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43 . An element with atomic number 18 has a valency of

18
6
8
0

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44 . A compound exhibitting multiple crystal structure is

allotropy
plymorhism
lattice
unit cell

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45 . The index of a plane that intercepts the three axes at a unit cell distance (3,2,1)

(6,3,2)
(1/2 1 1/2)
(6 2 1)
(2 3 6 )

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46 . Corrosion of metals involves

Physical reactions
chemical reaction
both
None of the mentioned

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47 . Difficult to monitor and very dangerous form of corrosion

galvanic
Pitting
Crevice
Stress

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48 . This form of corrosion occurs due to concentration difference in a component

Uniform
Galvanic
inter-granular
Stress

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49 . Which of the following can be used for cathodic protection:

Al
Cd
Cu
Either

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50 . Substitution solid solution involves

atoms of same sizes
atoms of different sizes
one smaller atom to fill the interstices
completely insolube

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