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All questions of Crystal Structure for GATE Physics Exam
The number of atoms per unit area of the plane [0 1 0] of a simple cubic crystal is :- a)4r2
- b)4r
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
The number of atoms per unit area of the plane [0 1 0] of a simple cubic crystal is :
a)
4r2
b)
4r
c)
d)
|
Pie Academy answered |
[0 1 0] is the miller indices of the plane, hence, the intercept will be 
the plane is in x-z plane passing through y = 1.
Now number of atoms in the plane for simple cubic lattice is =
⇒ Number of atoms per unit area of plane [0 1 0] of simple cubic lattice is,
(since, a = 2r).
The correct answer is:
the plane is in x-z plane passing through y = 1.Now number of atoms in the plane for simple cubic lattice is =
⇒ Number of atoms per unit area of plane [0 1 0] of simple cubic lattice is,
(since, a = 2r).The correct answer is:
Which of the following lattices has the least packing fraction?- a)fcc
- b)bcc
- c)simple cubic
- d)diamond
Correct answer is option 'D'. Can you explain this answer?
Which of the following lattices has the least packing fraction?
a)
fcc
b)
bcc
c)
simple cubic
d)
diamond
|
Jayant Mishra answered |
packing fraction of simple cubic = 52% packing fraction of bee = 68%
packing fraction of fee = 74%
packing fraction of diamond = 34%
The correct answer is: diamond
packing fraction of fee = 74%
packing fraction of diamond = 34%
The correct answer is: diamond
What is the second nearest neighbour distance in a face centered cubic whose conventional unit cell parameter is a?- a)a
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
What is the second nearest neighbour distance in a face centered cubic whose conventional unit cell parameter is a?
a)
a
b)
c)
d)
|
Vedika Singh answered |
Here AC is the nearest distance while AB or AD forms the nearest neighbour distance which is equal to ' a '.
The correct answer is: a
Which of the following has bcc structure?
- a)MgO
- b)CsCI
- c)MnO
- d)NaCI
Correct answer is option 'B'. Can you explain this answer?
Which of the following has bcc structure?
a)
MgO
b)
CsCI
c)
MnO
d)
NaCI
|
|
Jayant Mishra answered |
CsCl shows a body centred cubic lattice with a coordination number 8 for each ion.
For a NaCI crystal, the cell edge a = 0.563 nm. The smallest angle at which Bragg reflection can occur corresponds to a set of planes whose indices are :
- a)[1 1 0]
- b)[2 0 0]
- c)[1 0 0]
- d)[1 1 1]
Correct answer is option 'D'. Can you explain this answer?
For a NaCI crystal, the cell edge a = 0.563 nm. The smallest angle at which Bragg reflection can occur corresponds to a set of planes whose indices are :
a)
[1 1 0]
b)
[2 0 0]
c)
[1 0 0]
d)
[1 1 1]
|
|
Jayant Mishra answered |
The correct answer is Option 4: [1 1 1]. The smallest angle at which Bragg reflection can occur corresponds to a set of planes with indices [1 1 1]. This is because the interplanar spacing d of the crystal planes is equal to the unit cell dimension ao for NaCl crystals. Thus, for Bragg's law to be satisfied, the path length difference between waves effectively reflected by two adjacent planes must be equal to 2d sin 8, or mA, where m is an integer. For m = 1, the Bragg angle 8 is equal to arcsin (1/2a) which is equal to arcsin (1/2 x 0.563) = 54.7°. The Miller indices of the planes satisfying this condition are [1 1 1].
A body centred cubic lattice has edge a. Edge of its primitive cells will be :- a)
- b)
- c)
- d)a
Correct answer is option 'C'. Can you explain this answer?
A body centred cubic lattice has edge a. Edge of its primitive cells will be :
a)
b)
c)
d)
a
|
|
Vedika Singh answered |
from figure, AB = a
The correct answer is:
A reciprocal lattice is characterized by following primitive vectors
- a)fcc with cube edge π
- b)fcc with cube edge 2π
- c)bcc with cube edge π
- d)bcc with cube edge 2π
Correct answer is option 'C'. Can you explain this answer?
A reciprocal lattice is characterized by following primitive vectors
a)
fcc with cube edge π
b)
fcc with cube edge 2π
c)
bcc with cube edge π
d)
bcc with cube edge 2π
|
|
Jayant Mishra answered |
Hence, lattice is bcc with edge π
The correct answer is: bcc with cube edge π
Choose the correct option :- a)Reciprocal lattice of simple cubic lattice is simple cubic lattice
- b)Reciprocal lattice of bcc is fcc
- c)Reciprocal lattice o f simple cubic lattice is bcc
- d)Reciprocal lattice o f bcc is bcc
Correct answer is option 'A,B'. Can you explain this answer?
Choose the correct option :
a)
Reciprocal lattice of simple cubic lattice is simple cubic lattice
b)
Reciprocal lattice of bcc is fcc
c)
Reciprocal lattice o f simple cubic lattice is bcc
d)
Reciprocal lattice o f bcc is bcc
|
|
Vedika Singh answered |
Reciprocal lattice of simple cubic is always simple cubic whereas reciprocal lattice of bcc is fee and that of fee is bcc.
The correct answers are: Reciprocal lattice of simple cubic lattice is simple cubic lattice, Reciprocal lattice of bcc is fcc
The correct answers are: Reciprocal lattice of simple cubic lattice is simple cubic lattice, Reciprocal lattice of bcc is fcc
The positions of number of nearest neighbours in a unit cell of bcc structure is given by:- a)
- b)
- c)
- d)None of these
Correct answer is option 'A'. Can you explain this answer?
The positions of number of nearest neighbours in a unit cell of bcc structure is given by:
a)
b)
c)
d)
None of these
|
|
Vedika Singh answered |
Nearest neighbour to an atom (say at origin) is the atom present is the centre of the
at point P and the position of P can be =
The correct answer is: =
[3 2 6] are the miller indices of a plane, the intercept mode by the plane on the 3 crystallographic axes are:- a)(2a, 3b, c)
- b)(a, b, c)
- c)(a, 2b, 3c)
- d)None of the above
Correct answer is option 'A'. Can you explain this answer?
[3 2 6] are the miller indices of a plane, the intercept mode by the plane on the 3 crystallographic axes are:
a)
(2a, 3b, c)
b)
(a, b, c)
c)
(a, 2b, 3c)
d)
None of the above
|
|
Vedika Singh answered |
Miller indices are (3, 2, 6)
Hence, crystallographic axis are
The correct answer is: (2a, 3b, c)
Hence, crystallographic axis are
The correct answer is: (2a, 3b, c)
The primitive translation vectors of the fcc lattice are
The volume of the primitive cell of reciprocal lattice is : - a)
- b)
- c)
- d)
Correct answer is option 'D'. Can you explain this answer?
The primitive translation vectors of the fcc lattice are
The volume of the primitive cell of reciprocal lattice is :
The volume of the primitive cell of reciprocal lattice is :
a)
b)
c)
d)
|
|
Vedika Singh answered |
The primitive translation vector of the reciprocal lattice to the above lattice be calculated as :
Volume of the reciprocal lattice is :
The correct answer is:
Volume of the reciprocal lattice is :
The correct answer is:
For a simple cubic lattice d100 : d110 : d111 is.- a)
- b)
- c)
- d)6:3:2
Correct answer is option 'A'. Can you explain this answer?
For a simple cubic lattice d100 : d110 : d111 is.
a)
b)
c)
d)
6:3:2
|
|
Vedika Singh answered |
The correct answer is:
The basis vectors for a two dimensional lattice are given by :
if third vector 
where is a unit vector along z-a xis then,- a)reciprocal lattice vectors are
- b)value of
- c)reciprocal lattice vectors are
- d)
Correct answer is option 'B,C'. Can you explain this answer?
The basis vectors for a two dimensional lattice are given by :
if third vector where is a unit vector along z-a xis then,
if third vector where is a unit vector along z-a xis then,a)
reciprocal lattice vectors are
b)
value of
c)
reciprocal lattice vectors are
d)
|
|
Mister Genius answered |
whereas
are reciprocal lattice vectors.Now,
hence, putting these values, we get
The correct answers are: reciprocal lattice vectors are
The correct answers are: reciprocal lattice vectors are
Packing fraction of diamond cubic crystal structure is ____ % ?
Correct answer is '34'. Can you explain this answer?
Packing fraction of diamond cubic crystal structure is ____ % ?
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|
Vedika Singh answered |
Number of atoms in diamond crystal
Packing fraction
= 0.34
= 34%
The correct answer is: 34
Packing fraction
= 0.34
= 34%
The correct answer is: 34
)?
Atomic radius of copper (fcc) is 1.28Â , then density of copper is (kg/m3 )
Correct answer is '8260'. Can you explain this answer?
Atomic radius of copper (fcc) is 1.28Â , then density of copper is (kg/m3 )
|
|
Vedika Singh answered |
The correct answer is: 8260
What is the reciprocal lattice to simple cubic lattice?- a)fcc
- b)simple cubic
- c)hcp
- d)bcc
Correct answer is option 'B'. Can you explain this answer?
What is the reciprocal lattice to simple cubic lattice?
a)
fcc
b)
simple cubic
c)
hcp
d)
bcc
|
|
Pie Academy answered |
Primitive translation Vectors of simple cubic lattice may be written as :
Then primitive translation vector of reciprocal lattice is
Hence, the reciprocal lattice is itself a simple cubic lattice with lattice constant
The correct answer is: simple cubic
Then primitive translation vector of reciprocal lattice is
Hence, the reciprocal lattice is itself a simple cubic lattice with lattice constant
The correct answer is: simple cubic
Smallest angle of diffraction for an X-ray beam of wavelength 0.71
is (in degrees).
Correct answer is '5.6'. Can you explain this answer?
Smallest angle of diffraction for an X-ray beam of wavelength 0.71 is (in degrees).
is (in degrees).|
|
Vedika Singh answered |
For [1 1 1] Plane, 
For smallest angle,
⇒
The correct answer is: 5.6
For smallest angle,
⇒
The correct answer is: 5.6
Choose the correct feature(s) of miller indices :- a)All the parallel equidistant planes have the same miller indices.
- b)If the miller indices of two planes are [8 4 4] and [4 2 2], the planes are parallel to each other.
- c)A plane parallel to one of the co-ordinate axes has an intercept of infinity.
- d)None of the above
Correct answer is option 'A,B,C'. Can you explain this answer?
Choose the correct feature(s) of miller indices :
a)
All the parallel equidistant planes have the same miller indices.
b)
If the miller indices of two planes are [8 4 4] and [4 2 2], the planes are parallel to each other.
c)
A plane parallel to one of the co-ordinate axes has an intercept of infinity.
d)
None of the above
|
|
Jayant Mishra answered |
→ Miller indices give us an idea of the direction of the plane i.e. it tells us about the direction of normal to the plane and thus, it remains same for planes which are parallel.
→ [8 4 4] and [4 2 2] are equivalent.
→ If a plane is parallel to one of the coordinate axes, its miller indices for that particular direction is zero which indicates infinite intercept.
The correct answers are: All the parallel equidistant planes have the same miller indices., If the miller indices of two planes are [8 4 4] and [4 2 2], the planes are parallel to each other., A plane parallel to one of the co-ordinate axes has an intercept of infinity.
→ [8 4 4] and [4 2 2] are equivalent.
→ If a plane is parallel to one of the coordinate axes, its miller indices for that particular direction is zero which indicates infinite intercept.
The correct answers are: All the parallel equidistant planes have the same miller indices., If the miller indices of two planes are [8 4 4] and [4 2 2], the planes are parallel to each other., A plane parallel to one of the co-ordinate axes has an intercept of infinity.
The probability that a state which is 0.2eV above the fermi energy in a metal atom at 700K is?
Correct answer is '0.036'. Can you explain this answer?
The probability that a state which is 0.2eV above the fermi energy in a metal atom at 700K is?
|
|
Vedika Singh answered |
E - Ef = 0.2 eV
kB = 8.62 x 10-5 eVK-1
T = 700K
P = 0.036
The correct answer is: 0.036
kB = 8.62 x 10-5 eVK-1
T = 700K
P = 0.036
The correct answer is: 0.036
Choose the correct statement(s) for reciprocal lattice.- a)Any diffraction pattern of a crystal is a map of the reciprocal lattice of the crystal
- b)When a crystal is made to rotate both the direct lattice and reciprocal lattice and reciprocal lattice rotates
- c)The dimension of vectors in a reciprocal lattice is of (length)-1
- d)None of the above X
Correct answer is option 'A,B,C'. Can you explain this answer?
Choose the correct statement(s) for reciprocal lattice.
a)
Any diffraction pattern of a crystal is a map of the reciprocal lattice of the crystal
b)
When a crystal is made to rotate both the direct lattice and reciprocal lattice and reciprocal lattice rotates
c)
The dimension of vectors in a reciprocal lattice is of (length)-1
d)
None of the above X
|
|
Vedika Singh answered |
The correct answers are: Any diffraction pattern of a crystal is a map of the reciprocal lattice of the crystal, When a crystal is made to rotate both the direct lattice and reciprocal lattice and reciprocaj lattice rotates, The dimension of vectors in a reciprocal lattice is of (length)-1
If a two - dimensional lattice has the basic vector 
hen the vectors of the reciprocal lattice are respectively;- a)
- b)
- c)
- d)
Correct answer is option 'A'. Can you explain this answer?
If a two - dimensional lattice has the basic vector hen the vectors of the reciprocal lattice are respectively;
hen the vectors of the reciprocal lattice are respectively;a)
b)
c)
d)
|
|
Vedika Singh answered |
The vectors of reciprocal lattice are
The correct answer is:
If d be the space between parallel lattice planes and 
be reciprocal lattice vector, then which of the following relations are true?- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
If d be the space between parallel lattice planes and be reciprocal lattice vector, then which of the following relations are true?
be reciprocal lattice vector, then which of the following relations are true?a)
b)
c)
d)
|
|
Vedika Singh answered |
If 
is unit vector normal to the plane, then
If d is the interplanar. distance,
where
is the translation vector along one of the unit axis.
Here the planes are perpendicular to this unit axis
The correct answer is:
is unit vector normal to the plane, thenIf d is the interplanar. distance,
where
is the translation vector along one of the unit axis.Here the planes are perpendicular to this unit axis
The correct answer is:
Be has hexagonal closed packed structure with smaller lattice parameter equal to 2.29
. Concentration of electron in Be crystal is in terms of 1029 m-3 .
Correct answer is '8.15'. Can you explain this answer?
Be has hexagonal closed packed structure with smaller lattice parameter equal to 2.29. Concentration of electron in Be crystal is in terms of 1029 m-3 .
. Concentration of electron in Be crystal is in terms of 1029 m-3 .|
|
Jayant Mishra answered |
Here a = 2.29 
for hexagonal close packing
There are two atoms in primitive cell and each atom carries 4 electrons.
The correct answer is: 8.15
for hexagonal close packingThere are two atoms in primitive cell and each atom carries 4 electrons.
The correct answer is: 8.15
Nearest neighbour distance in Na crystal is 1 . 8 3 
Density of electrons in Na crystal in m-3 is :
Correct answer is '0.212'. Can you explain this answer?
Nearest neighbour distance in Na crystal is 1 . 8 3 Density of electrons in Na crystal in m-3 is :
Density of electrons in Na crystal in m-3 is :|
|
Pie Academy answered |
Na has bcc structure.
Nearest neighbour distance
The correct answer is: 0.212
Nearest neighbour distance
The correct answer is: 0.212
What is the second nearest neighbour distance in bcc crystal whose conventional unit cell parameter is a?- a)
- b)
- c)
- d)a
Correct answer is option 'D'. Can you explain this answer?
What is the second nearest neighbour distance in bcc crystal whose conventional unit cell parameter is a?
a)
b)
c)
d)
a
|
|
Pie Academy answered |
In a bcc structure, for any atom at the corner of the lattice, nearest neighbour is at the centre of the lattice which is at a distance of 
The second nearest neighbour is at the adjacent corners of the lattice at a distance of 'a'.
The correct answer is: a
The second nearest neighbour is at the adjacent corners of the lattice at a distance of 'a'.The correct answer is: a
Metallic monovalent sodium crystallizes in bcc structures. If the length of unit cell is 4 x 10-8 cm. The concentration of conduction electrons in metallic sodium is x * 1022 cm-3 . Find x?
Correct answer is '3.125'. Can you explain this answer?
Metallic monovalent sodium crystallizes in bcc structures. If the length of unit cell is 4 x 10-8 cm. The concentration of conduction electrons in metallic sodium is x * 1022 cm-3 . Find x?
|
|
Vedika Singh answered |
Sodium has one conduction electron and bcc structure, for bcc structure, number of atoms in unit cell = 2.
Number of conduction electrons = 2x1 =2.
Concentration
The correct answer is: 3.125
Number of conduction electrons = 2x1 =2.
Concentration
The correct answer is: 3.125
Which is/are correct for simple cubic lattice?- a)The volume of unit cell of reciprocal of simple cubic lattice is a3 .
- b)The volume of unit cell of simple cubic lattice is a3 (where a is the edge)
- c)Volume of unit cell in reciprocal lattice is
- d)The lattice constant is
for reciprocal of simple cubic lattice.
Correct answer is option 'B,C,D'. Can you explain this answer?
Which is/are correct for simple cubic lattice?
a)
The volume of unit cell of reciprocal of simple cubic lattice is a3 .
b)
The volume of unit cell of simple cubic lattice is a3 (where a is the edge)
c)
Volume of unit cell in reciprocal lattice is
d)
The lattice constant is for reciprocal of simple cubic lattice.
for reciprocal of simple cubic lattice.|
|
Vedika Singh answered |
For simple cubic lattice, volume of unit cell = a3
⇒ lattice constant is
for reciprocal of simple cubic lattice
⇒ volume of unit cell in reciprocal lattice is
The correct answers are: The volume of unit cell of simple cubic lattice is a3 (where a is the edge), The lattice constant is
for reciprocal of simple cubic lattice.,
Volume of unit cell in reciprocal lattice is
⇒ lattice constant is
for reciprocal of simple cubic lattice⇒ volume of unit cell in reciprocal lattice is
The correct answers are: The volume of unit cell of simple cubic lattice is a3 (where a is the edge), The lattice constant is
for reciprocal of simple cubic lattice.,Volume of unit cell in reciprocal lattice is
A copper wire of uniform cross-sectional area 10 x 10-6 m-2 carries a current of 1 
Assuming that each copper atom contributes one electron to the electron gas, the drift velocity of free electron in units of µm/sec is :
of copper is 8.94 x 103 kg/m3 and its atomic mass is 1.05 x 10-25 kg).
Correct answer is '74'. Can you explain this answer?
A copper wire of uniform cross-sectional area 10 x 10-6 m-2 carries a current of 1 Assuming that each copper atom contributes one electron to the electron gas, the drift velocity of free electron in units of µm/sec is :
of copper is 8.94 x 103 kg/m3 and its atomic mass is 1.05 x 10-25 kg).
Assuming that each copper atom contributes one electron to the electron gas, the drift velocity of free electron in units of µm/sec is : of copper is 8.94 x 103 kg/m3 and its atomic mass is 1.05 x 10-25 kg).|
|
Pie Academy answered |
The correct answer is: 74
Volume of primitive cell of bcc structure having conventional lattice parameter a is :- a)
- b)2a3
- c)a3
- d)
Correct answer is option 'A'. Can you explain this answer?
Volume of primitive cell of bcc structure having conventional lattice parameter a is :
a)
b)
2a3
c)
a3
d)
|
|
Pie Academy answered |
For bcc structure :
The correct answer is:
The correct answer is:
If the angle between direction of X-ray (incident) and diffracted one is 16°, the angle of incidence in degrees will be :
Correct answer is '82'. Can you explain this answer?
If the angle between direction of X-ray (incident) and diffracted one is 16°, the angle of incidence in degrees will be :
|
|
Vedika Singh answered |
⇒ 2θ = 180°
⇒ θ = 82°
The correct answer is: 82
Given that density of sodium is 0.971 g/cm3 and atomic weight is 23. If h = 6.63 * 10¯34 Js, mass of electron = 9.11 x 10-31 kg and Avogadro’s number is 6.02 x 1023 atoms/mol. Assuming each sodium atom contribute one electron to the electron gas. What is the electron density in units of 1028 Im3 ?
Correct answer is '2.54'. Can you explain this answer?
Given that density of sodium is 0.971 g/cm3 and atomic weight is 23. If h = 6.63 * 10¯34 Js, mass of electron = 9.11 x 10-31 kg and Avogadro’s number is 6.02 x 1023 atoms/mol. Assuming each sodium atom contribute one electron to the electron gas. What is the electron density in units of 1028 Im3 ?
|
|
Jayant Mishra answered |
Electron density of sodium 
The correct answer is: 2.54
The correct answer is: 2.54
A crystal belongs to a face cubic lattice with four atoms in the unit cell. The size of crystal is 1cm and its unit cell dimension is 1nm.Then the number of atoms in the crystal is in unit of 1021 is?
Correct answer is '4'. Can you explain this answer?
A crystal belongs to a face cubic lattice with four atoms in the unit cell. The size of crystal is 1cm and its unit cell dimension is 1nm.Then the number of atoms in the crystal is in unit of 1021 is?
|
|
Vedika Singh answered |
Crystal size = 1 cm
Size of unit cell = 1 nm
For fee structure, number of atoms per unit cell = 4
Number of atoms = 4x1021
The correct answer is: 4
Size of unit cell = 1 nm
For fee structure, number of atoms per unit cell = 4
Number of atoms = 4x1021
The correct answer is: 4
A molecule belongs to hep structure, then- a)total number of atoms in unit cell are 6
- b)co-ordination number is 12
- c)packing fraction is 74%
- d)none of the above
Correct answer is option 'A,B,C'. Can you explain this answer?
A molecule belongs to hep structure, then
a)
total number of atoms in unit cell are 6
b)
co-ordination number is 12
c)
packing fraction is 74%
d)
none of the above
|
|
Pie Academy answered |
Total number of atoms/unit cell =
Co-ordinate number = 6 + 3 + 3 = 12 Packing fraction for hep = 74%
The correct answers are: total number of atoms in unit cell are 6, co-ordination number is 12, packing fraction is 74%
Choose the correct statement:- a)packing fraction for simple cubic is 68%
- b)packing fraction for simple cubic structure is 52%
- c)packing fraction for bcc cubic structure is 52%
- d)packing fraction for bcc cubic structure is 68%
Correct answer is option 'B,D'. Can you explain this answer?
Choose the correct statement:
a)
packing fraction for simple cubic is 68%
b)
packing fraction for simple cubic structure is 52%
c)
packing fraction for bcc cubic structure is 52%
d)
packing fraction for bcc cubic structure is 68%
|
|
Jayant Mishra answered |
Packing fraction for simple cubic is 52% and packing fraction for bcc is 68%
The correct answers are: packing fraction for simple cubic structure is 52%, packing fraction for bcc cubic structure is 68%
The correct answers are: packing fraction for simple cubic structure is 52%, packing fraction for bcc cubic structure is 68%
Which is/are correct for fcc structure?
- a)packing factor is 68%
- b)number of atoms in unit cell are 4
- c)number of atoms in unit cell are 2
- d)packing factor is 74%
Correct answer is option 'B,D'. Can you explain this answer?
Which is/are correct for fcc structure?
a)
packing factor is 68%
b)
number of atoms in unit cell are 4
c)
number of atoms in unit cell are 2
d)
packing factor is 74%
|
|
Jayant Mishra answered |
packing fraction for fcc is 74% and 
atoms / unit cell.
The correct answers are: number of atoms in unit cell are 4, packing factor is 74%
atoms / unit cell.The correct answers are: number of atoms in unit cell are 4, packing factor is 74%
is :
In crystallographic notations, the vector 
is the cubic cell shown is the figure is :
- a)[1 1 2]
- b)[1 2 1]
- c)[1 2 2]
- d)[2 2 1]
Correct answer is option 'D'. Can you explain this answer?
In crystallographic notations, the vector is the cubic cell shown is the figure is :
is the cubic cell shown is the figure is :a)
[1 1 2]
b)
[1 2 1]
c)
[1 2 2]
d)
[2 2 1]
|
|
Pie Academy answered |
Coordinates of point
is , hence, in crystal notation the plane is [2 2 1]
The correct answer is: [2 2 1]
is , hence, in crystal notation the plane is [2 2 1]The correct answer is: [2 2 1]
If 0.28nm is spacing between the nearest neighbouring ions in NaCI lattice, the unit cell parameter in 
is?
Correct answer is '5.6'. Can you explain this answer?
If 0.28nm is spacing between the nearest neighbouring ions in NaCI lattice, the unit cell parameter in is?
is?|
|
Vedika Singh answered |
r - 0.28 nm
⇒ 2r = 0.56 nm
= 5.6
The correct answer is: 5.6
⇒ 2r = 0.56 nm
= 5.6
The correct answer is: 5.6
Sodium contains 2.54 x1022 free electrons per cm3 ( given = 6.63 x 10 -34 J-s, m= 9 .11 x 10-31 kg , kB = 1.38 x 10-23 JIK and 1eV = 1.6 x 10-19 J ) , then Fermi D 4 temperature is given in terms of 104 K as?
Correct answer is '3.6'. Can you explain this answer?
Sodium contains 2.54 x1022 free electrons per cm3 ( given = 6.63 x 10 -34 J-s, m= 9 .11 x 10-31 kg , kB = 1.38 x 10-23 JIK and 1eV = 1.6 x 10-19 J ) , then Fermi D 4 temperature is given in terms of 104 K as?
|
|
Vedika Singh answered |
We know that 
⇒
The correct answer is: 3.6
⇒
The correct answer is: 3.6
For simple cubic structure, the correct statements are :- a)Co-ordination number are 6
- b)Number of lattice point is equal to one
- c)Co-ordination number is 8
- d)Number of lattice point is equal to two
Correct answer is option 'A,B'. Can you explain this answer?
For simple cubic structure, the correct statements are :
a)
Co-ordination number are 6
b)
Number of lattice point is equal to one
c)
Co-ordination number is 8
d)
Number of lattice point is equal to two
|
|
Jayant Mishra answered |
For atom at A, there are 4 adjacent neighbours in the x-y plain and 2 neighbours along z-axis, one above and the other below the plane.
Hence, coordination number is 6.
Now
⇒ lattice point is equal to one.
The correct answers are: Co-ordination number are 6, Number of lattice point is equal to one
Masses of ionic radii of Na+ and CI– in NaCI crystals are 22.99 amu, 0.98A and 35.45 amu, 1.82A respectively. What is the packing fraction of NaCI?
Correct answer is '0.66'. Can you explain this answer?
Masses of ionic radii of Na+ and CI– in NaCI crystals are 22.99 amu, 0.98A and 35.45 amu, 1.82A respectively. What is the packing fraction of NaCI?
|
|
Jayant Mishra answered |
Lattice parameter a = 
a = 2 [0.98 + 1.82]
a = 5.6A
Each unit cell contains 4 atoms.
Packing fraction =
Packing fraction =
Packing fraction = 0.66
The correct answer is: 0.66
a = 2 [0.98 + 1.82]
a = 5.6A
Each unit cell contains 4 atoms.
Packing fraction =
Packing fraction =
Packing fraction = 0.66
The correct answer is: 0.66
0.71 Â wavelength X-ray is diffracted with a simple cubic crystal having edge a = 2.814 Â for the plane (110) then :
- a)for 2nd order
- b)for 2nd order
- c)d110 = 1.99Â
- d)d110 = 1.59Â
Correct answer is option 'B,C'. Can you explain this answer?
0.71 Â wavelength X-ray is diffracted with a simple cubic crystal having edge a = 2.814 Â for the plane (110) then :
a)
for 2nd order
b)
for 2nd order
c)
d110 = 1.99Â
d)
d110 = 1.59Â
|
|
Vedika Singh answered |
By Bragg's law:
The correct answers are:
Consider the atomic packing factor (APF) of the following crystal structures :
P. Simple cubic
Q. Body centred cubic
R. Face centred cubic
S. Diamond T. Hexagonal close packed
Q. Which two of the above structure have equal APF?- a)R and S
- b)R and T
- c)S and T
- d)P and Q
Correct answer is option 'B'. Can you explain this answer?
Consider the atomic packing factor (APF) of the following crystal structures :
P. Simple cubic
Q. Body centred cubic
R. Face centred cubic
S. Diamond T. Hexagonal close packed
Q. Which two of the above structure have equal APF?
P. Simple cubic
Q. Body centred cubic
R. Face centred cubic
S. Diamond T. Hexagonal close packed
Q. Which two of the above structure have equal APF?
a)
R and S
b)
R and T
c)
S and T
d)
P and Q
|
|
Jayant Mishra answered |
simple cubic → 52%, bcc → 68%, fcc → 74%, diamond → 34%, hcp 74%
The correct answer is: R and T
The correct answer is: R and T
If 
is wave vector of incident X-ray and be the reciprocal lattice vector then condition for Bragg reflection is given by :- a)
- b)
- c)
- d)
Correct answer is option 'B'. Can you explain this answer?
If is wave vector of incident X-ray and be the reciprocal lattice vector then condition for Bragg reflection is given by :
is wave vector of incident X-ray and be the reciprocal lattice vector then condition for Bragg reflection is given by :a)
b)
c)
d)
|
|
Pie Academy answered |
Correct Answer :- b
Explanation : Bragg reflection or diffraction occurs when light waves are incident on an ultrasonic wave with a comparable wavelength. The light is reflected in a specular fashion by the ultrasonic grating, and undergoes constructive interference in accordance with Bragg's law.
Let be the scattered wave vector, then from Ewald construction :
K' = K - G....(i)
Since, for elastic scattering, there will be no change in the magnitude of the vector i.e.
|K| = K' = 2π/λ
Now squaring (i),
K2 = K2 + G2 - 2K . G
G2 = 2K . G
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