Solid State Physics-I - Quanta: BS/MSc Physics Books

1: FCC lattice is the reciprocal lattice of the

a. BCC lattice

b. SC lattice

c. HCP lattice

d. Both b and c

2: The pure rotational symmetry which is not possible in crystalline solid is

a. 2-fold

b. 3-fold

c. 4-fold

d. 5-fold

3: The distance between the adjacent atomic planes in CaCO₃ is 0.2nm. The smallest Bragg scattering for 0.03nm X-ray is

a. $\mathbf{2}.\mathbf{9}°$

b. $1.5°$

c. 0.29°

d. 5.8°

4: The number of two-dimensional lattices are

a. 3

b. 5

c. 7

d. 9

5: The structure factors for (010) and (200) reflections respectively, in face centred cubic lattice are

a. $2f\ and\ zero$

b. $\mathbf{Zero}\ \mathbf{and}\ \mathbf{4f}$

c. $\mathbf{Zero}\ \mathbf{and}\ \mathbf{4f}$

d. Zero and zero

6: Packing fraction of an FCC lattice is

a. 0.52

b. 0.32

c. 0.74

d. 0.62

7: The number of lattice points in a primitive cell is

a. 2

b. 3

c. 4

d. 1

9: The volume of primitive cell of the FCC reciprocal lattice is

a. $4({\frac{2\pi}{a})}^3$

b. $4({\frac{\pi}{a})}^3$

c. $4({\frac{\pi}{2a})}^3$

d. $4({\frac{3\pi}{a})}^3$

10: $\mathbf{\ _K^\rightarrow}$ is the wave vector of incident light $|\vec{K|}=\frac{2\pi}{\lambda}$ , λ is wavelength of the light, and $\vec{G}$ is reciprocal lattice vector, then the Bragg’s law can be written as

a. $\vec{k} + \vec{G} =0$

b. $\mathbf{\vec{2K.G} + \vec{G^2} =0}$

c. $\vec{2K.G} + \vec{K^2} =0$

d. $\vec{K}.\vec{G}=0$

11: The De-Broglie wavelength associated with an electron of mass m and accelerated by a potential V is

a. $\frac{\mathbf{h}}{\sqrt{\mathbf{2}\mathbf{m}_\mathbf{e}\mathbf{V}}}$

b. $\frac{\sqrt{2m_eV}}{h}$

c. $\frac{h}{\sqrt{eVm}}$

d. $\frac{h}{2m_eV}$

12: Crystal structure consists of

a. Space lattice

b. Basis

c. Both a and b

d. None of these

13: Packing density is maximum for

a. Simple cubic lattice

b. Body centred cubic lattice

c. Face centred cubic lattice

d. All of these

14: Packing fraction is minimum for

a. Face centred cubic lattice

b. Body centred cubic lattice

c. Simple cubic lattice

d. All of above

15: Primitive cell has

a. Maximum volume

b. Zero volume

c. Atoms at corners of unit cell

d. None of above

16: Packing density of Diamond crystal is

a. 52%

b. 74%

c. 68%

d. 34%

17: NaCl crystal has……. structure

a. FCC

b. BCC

c. HCP

d. None of above

18: Miller Indices of a plane having intercepts 2,2, are

a. (001)

b. (120)

c. (002)

d. (110)

19: Number of atoms per unit cell in lattice are

a. 1

b. 2

c. 4

d. 6

**20: Coordination number of f_cc lattice is**

a. 6

b. 8

c. 0

d. 12

21: Packing density of bcc lattice is

a. 52%

b. 68%

c. 74%

d. 85%

22: Cubic crystal is defined by

a. $\mathbf{a=b=c \ \ \ \ \alpha = \beta = \gamma=90^o }$

b. $a=b=c\ \ \alpha=\beta=\gamma=120$

c. $a\neq b=c\ \ \alpha=\beta=\gamma=90$

d. $a\neq b\neq c\ \ \alpha=\beta=\gamma=90^o$

23: A crystal cannot have …………fold symmetry

a. Two

b. Four

c. Five

d. Six

24: A polyhedral block which fill whole of space by action of some suitable translation operation is called

a. Primitive cell

b. Unit cell

c. Wigner Seitz cell

d. Amorphous solid

25: The process in which solid grows is the key whether a solid is

a. Isotropic

b. Anisotropic

c. Both a and b

d. None of these

26: Regular and periodic arrangement of atoms /molecules/ions in solid is due to tendency of them to settle down in state of

a. Minimum energy

b. Maximum energy

c. Free energy

d. Helmholtz energy

27: Rectangular primitive lattice is invariant under

a. Mirror reflection symmetry

b. Inversion symmetry

c. Translation symmetry

d. All of above

28: Tetragonal lattice has………. Fold symmetry

a. Four

b. One

c. Two

d. Six

29: A solid showing neither rectangular nor granular is known as

a. Non-crystalline

b. Amorphous

c. Both a and b

d. Crystalline

30: Inversion is ………symmetry

a. Point

b. Plane

c. Space

d. All of above

31: The vacant interstitial space between the close packed atoms is called

a. Basis

b. Polytypism

c. Void

d. None of above

32: The maximum energy that X-ray photon can have cannot exceed maximum energy of

a. Proton beam

b. Electron beam

c. Neutron beam

d. All of above

33: The shortest wavelength that is present in X-rays produced at an accelerating potential of 50kV is

a. 428A

b. 0.25A

c. 5126m

d. 0.25m

34: Mosley plotted a graph between atomic number of elements and square root of frequencies of characteristic X-rays, which was

a. A curve

b. Parabola

c. Hyperbola

d. Straight line

35:When X-rays are passed through a material , the intensity of transmitted beam is ……….that of incident beam

a. Greater than

b. Equal to

c. Less than

d. Insufficient data

36: Bragg’s equation is a consequence of

a. Schrodinger equation

b. Laue equations

c. Miller indices

d. Diamond structure

37: A crystal lattice may be considered as an assembly of various different sets of equidistant………..planes

a. Parallel

b. Perpendicular

c. Reflecting

d. Diffracting

38: The 1^st Brillion zone of a bcc lattice is a twelve faced solid called rhombic

a. Octahedron

b. Dodecahedron

c. Triangle

d. None of these

39: Every reciprocal lattice vector $\vec{G}$ is ……….to plane of crystal lattice (hkl)

a. Tangent

b. Equal

c. Normal

d. None of these

40: The interplanar spacing $d_{hk}$ in a real crystal lattice is equal to

a. $\frac{a}{h}$

b. $\frac{\mathbf{2\pi}}{\mathbf{G}}$

c. $\frac{G}{2\pi}$

d. None of above

41: Reciprocal of a reciprocal lattice is …………..lattice

a. Direct

b. Reciprocal

c. Normal

d. Brillion zone

42: Volume of a unit cell of reciprocal lattice is inversely proportional to that of corresponding

a. Reciprocal lattice

b. Direct lattice

c. Primitive cell

d. Unit cell

**43: The 1^st Brillion zone of a f_cc lattice is a fourteen faced solid called truncated**

a. Octahedron

b. Dodecahedron

c. Square

d. None of above

44: The atomic scattering factor is a measure of ………..an atom in scattering X-rays

a. Wavelength

b. Frequency

c. Volume

d. Efficiency

45: The Powder method is the most convenient method for obtaining diffraction data and is readily applicable to all

a. Liquids and gases

b. Solids

c. Crystalline materials

d. All

46: Neutron diffraction differs from X-ray diffraction in sense of that X-rays are scattered by electron clouds whereas neutrons are scattered by

a. Electrons and holes

b. Nuclei of atoms

c. Photons

d. Mesons

47: Except of ………….all the metals are solid

a. Na

b. Mg

c. Hg

d. Al

48: Non-metals are

a. Malleable

b. Ductile

c. Both

d. None of these

49: In diamond, bonding occurs in geometry

a. Tetrahedral

b. Trigonal

c. Tetragonal

d. All of these

50: The ratio of ionic radii is denoted by

a. $\frac{r^<}{r^>}$

b. $\frac{\mathbf{r}^>}{\mathbf{r}^<}$

c. $\frac{r^=}{r^>}$

d. $\frac{r^<}{r^=}$

51: The compressibility K is defined as

a. $\frac{\mathbf{1}}{\mathbf{B}}$

b. B

c. $\sqrt B$

d. B²

52: The stiffness constant S’ s has the dimensions of

a. $\mathbf{\frac{[Area]}{[Force]}}$

b. $\frac{[Force]}{[Area]}$

c. $\frac{[Energy]}{[Volume]}$

d. None of these

53: The compliance constant C’ s has the dimensions of

a. $\frac{[Area]}{[Force]}$

b. $\frac{[Force]}{[Area]}$

c. $\frac{[Force]}{[Area]}$

d. Both b and c

54: $\mathbf{e_{xy}=\ldots?}$

a. $\mathbf{\epsilon}{\mathbf{yx}}{+\mathbf{\epsilon}}{\mathbf{xy}}$

b. $\epsilon_{zy}{+\epsilon}_{yz}$

c. $\epsilon_{zx}{+\epsilon}_{xz}$

d. All of these

55: The ionic radius of Al⁺³ is

a. 0.102

b. 0.212

c. 0.054

d. 0.072

56: Both O^-2 and Mg⁺² has 10 electrons, but they don’t have the same

a. Charge

b. Ionic radius

c. Electronic configuration

d. All of these

57: In Equation $\mathbf{V\left(r\right)=[({\frac{\sigma}{r})}^{12}-\left({\frac{\sigma}{r})}^6\right]}$ the term $({\frac{\sigma}{r})}^6$ denotes

a. Repulsion

b. Attraction

c. Both

d. None of these

58: The Leonard-Jones potential is a function of

a. Time

b. Velocity

c. Distance

d. All of these

59: As the separation distance decreases below equilibrium, then the potential energy becomes

a. Decreases

b. Increases

c. Moderate

d. All of these

60: Cohesive energy is generally expressed in

a. eV per atom

b. J

c. eV

d. None of these

61: The attractive and repulsive forces are balance each other when

a. $r>r_0$

b. rVr₀

c. r = r₀

d. $r\geq r_0$

62: Equilibrium density r₀ of solid noble gases is

a. 1.09

b. -1.09

c. 1.09

d. $-1.09\epsilon$

63: Equilibrium cohesive energy µ(r_o) of solid noble gases is

a. $8.6\epsilon$

b. $-\mathbf{8}.\mathbf{6\epsilon}$

c. $8.6\sigma$

d. $-8.6\sigma$

64: The Madelung constant M is defined as

a. 2ln 2

b. 2ln3

c. 3ln2

d. ln2

65: The value of Madelung constant is

a. $-1.38\ per\ molecule$

b. $0.38\ per\ molecule$

c. $\mathbf{1}.\mathbf{38}\ \mathbf{per}\ \mathbf{molecule}$

d. None of these

66: The equation $M=\frac{6}{1}-\frac{12}{2}+\frac{8}{3}-\frac{6}{4}+\frac{24}{5}\ldots$ is applicable only for

a. H₂O

b. MgCl₂

c. KCl

d. NaCl

67: Madelung constant for one dimensional ionic crystal is

a. 2ln 2

b. 2

c. ln 2

d. None of these

68: The potential energy of a system of two particles is $U=-\frac{A}{r^n}+\frac{B}{r^m}$ For this system to be stable, the condition is

a. n=m

b. n<m

c. $\mathbf{m}>\mathbf{n}$

d. None of these

69: NaCl is a ……….molecule

a. Polar

b. Non-polar

c. Both

d. None of above

70: The lowest melting point is found in crystalline solid having……bonds

a. Metallic

b. Covalent

c. Ionic

d. Vander Waals

71: Which statement is correct?

a. Hydrogen bond increases the bonding of water H₂O

b. Hydrogen bond decreases the bonding of water H₂O

c. Hydrogen bond is non-directional

d. All of these

72: In metallic bonds

a. All electrons are bounded

b. Most electrons are free

c. Both a and b

d. None of these

73: Metals can exist in ….state only because there are forces of attraction acting between atoms when they are brought close to each other

a. Solid

b. Liquid

c. Plasma

d. All of above

74: Vander Waal bonding is …….of all bonding

a. Strongest

b. Weakest

c. Energetic

d. All of above

75: The cohesive energy of ionic crystals is mainly due to

a. Electrostatic repulsion

b. Gravitational attraction

c. Magnetic attraction

d. Electrostatic attraction

76: Carbon in the form of diamond, CCl_4,CH₄ etc. exhibit……covalent bonding

a. Sp³—tetrahedral

b. sp²—tetrahedral

c. sp³-covalent

d. All of these

77: Covalently bonded atoms often produce a configuration that behaves like an

a. Electric dipole

b. Magnetic dipole

c. Both a & b

d. None of these

78: An atom without its valence electrons is called

a. Metal

b. Crystal

c. Ion-core

d. None of these

79: The longitudinal stiffness C is defined as

a. $\mathbf{a\alpha}$

b. $\alpha\beta$

c. $b\alpha$

d. None of these

80: $v_s=\sqrt{\frac{C}{\rho}}$ is constant for given lattice and has the dimensions of

a. Mass

b. Time

c. Volume

d. Velocity

81: Under what condition, dispersion effect is negligible and medium behaves like a homogeneous continuous?

a. $v_p=v_g{\neq v}_s$

b. $v_p\neq v_g{\neq v}_s$

c. $\mathbf{v}\mathbf{p}=\mathbf{v}\mathbf{g}{=\mathbf{v}}_\mathbf{s}$

d. All of these

82: The ratio of amplitude at K=0, for the acoustical branch is

a. $\frac{U}{V}=0$

b. $\frac{\mathbf{U}}{\mathbf{V}}=\mathbf{1}$

c. $\frac{U}{V}=-1$

d. $\frac{U}{V}=\infty$

83: At the zone boundary, the frequency of acoustical branch depends upon

a. Lower mass(M₁)

b. higher mass(M₂)

c. Both

d. None of these

84: If the crystal structure is unstable, then will be

a. Imaginary, negative

b. Imaginary, positive

c. Negative, imaginary

d. Positive, imaginary

86: The number of vector N is … operator

a. Parity

b. Projection

c. Identity

d. Hermitian

87: The action of $a\ on\ |n>$ generates a new state $|n-1>$ with eigen value

a. n

b. n-1

c. √n

d. √n-1

88: The action of $a\ on\ |n>$ generates a new state |n+1〉 with eigen value

a. n

b. n+1

c. √

d. √n+1

89: The Dulong-Petit law fails near room temperature (300 K) for manu light elements because their Debye temperature is:

a. >>300 K

b. ~300 K

c. <<300 K

d. 0 K

90: According to Dulong-Petit law, the specific heat of a solid

a. Proportional to temperature

d. Doesn’t depends on temperature

c. Depends on square of temperature

d. Inversely proportional to temperature

91: The specific heat due to free electrons in metal varies as

a. $\mathbf{C}_\mathbf{V}\propto\mathbf{T}$

b. $C_V\propto T^2$

c. $C_V=constant$

d. $C_V\propto\frac{1}{T}$

92: The lattice specific heat at constant volume C_V of a solid at lower temperature depends on temperature T as

a. $C_V\propto T$

b. $C_V\propto T^2$

c. $\mathbf{C}_\mathbf{V}\propto\mathbf{T}^\mathbf{3}$

d. $C_V\propto\frac{1}{T}$

93: The equation $C_V=3R$ denotes the

a. Einstein’s law

b. Dulong-Petit law

c. Debye law

d. None of these

94: The magnitude of group velocity $v_g$ is defined as

a. $|\mathbf{\nabla}_\mathbf{k}\mathbf{\omega}|$

b. $\nabla_k\omega$

c. ${-2\nabla}_k\omega$

d. ${-\nabla}_k\omega$

95: Einstein’s temperature $\theta_E$ is defined as

a. $\frac{\mathbf{h}\mathbf{v}\mathbf{E}}{\mathbf{k}\mathbf{B}\mathbf{T}}$

b. $\frac{v_E}{k_B}$

c. $\frac{\mathbf{h}}{\mathbf{k}_\mathbf{B}}$

d. $\frac{\mathbf{h}\mathbf{v}\mathbf{E}}{\mathbf{k}\mathbf{B}}$

96: The Einstein’s model explains the observed specific heat of solid at temperature

a. Low

b. Normal

c. High

d. All of these

97: Cuttoff wave vector K_D is defined as

a. $\frac{\mathbf{\omega}_\mathbf{D}}{\mathbf{v}}$

b. $\frac{v}{\omega_D}$

c. $\frac{hv}{\omega_D}$

d. None of these

99: At ordinary temperature, contribution of electronic heat capacity to the heat capacity of solids is

a. Small

b. Infinite

c. Large

d. None of these

100: In Einstein theory of specific heat of solids, the atoms in solid are assumed as

a. Coupled oscillator

b. Independent oscillator

c. Damped oscillator

d. None of above

101: Lattice vibrations are

a. Longitudinal

b. Transverse

c. Both a and b

d. None of these

102: The momentum of phonon is

a. $\hbar\mathbf{k}^\rightarrow$

b. $\hbar w$

c. Zero

d. None of these

103: Energy of elastic waves is always

a. Zero

b. Continuous

c. Quantized

d. Cannot be predicted

104: According to Einstein model, as temperature approaches to zero, lattice contribution to heat capacity of solid approaches to

a. Infinity

b. Zero

c. Any value

d. Constant large value

105: The assumption that the atoms in a lattice are coupled together is taken into account for variation of heat capacity of solid by

a. Dulong and Petit

b. Einstein

c. Debye

d. All of above

106: For what value of k stationary waves are set up in one dimensional lattice?

a. $\mathbf{k}=\mathbf{\pi}/\mathbf{a}$

b. $k=2\pi/a$

c. $k\rightarrow0$

d. $k=4\pi/a$

107: The quantum energy associated with an elastic wave is called

a. Photon

b. Neutron

c. Phonon

d. All of above

108: The concept of quantized lattice vibrations helps to explain a number of properties of solids such as………near absolute zero

a. Volume of solid

b. Pressure of solid

c. Heat capacity

d. All of above

109: The velocity with which the wave crests and troughs travel through a medium is called

a. Group velocity

b. Phase velocity

c. Uniform velocity

d. Average velocity

110: A phonon is emitted or absorbed in ………. scattering of photon by crystal

a. Elastic

b. Inelastic

c. Both a and b

d. None of above

111: Dulong and Petit law fails at

a. Low temperature

b. High temperature

c. Both a and b

d. None of these

112: In the long wavelength limit, for mono-atomic linear lattice, phase velocity is……. group velocity

a. Less than

b. Greater than

c. Equal to

d. Not known

113: The frequency range between top of acoustic branch and bottom of optical branch is

a. Allowed

b. Forbidden

c. Band gap

d. Nil

114: Theoretical strength is about ………times to average real strength of a material

a. 1

b. 10

c. 100

d. 1000

115: Following is not the 2-dimensional imperfection

a. Twin boundary

b. Dislocation

c. Surface

d. Grain boundary

116: Figure out the odd one in the following

a. Frenkel defect

b. Tilt boundary

c. Twist boundary

d. Stacking fault

117: Thermodynamically stable defects

a. Point defects

b. Line defects

c. Surface defects

d. Volume defects

118: Taylor dislocation cannot move by the following way

a. Slip

b. Climb

c. Cross-slip

d. All of these

119: Conservative movement of dislocations

a. Slip

b. Climb

c. Both a and b

d. None

120: Burgers vector changes with

a. Kind of dislocation

b. Length of dislocation

c. Both kind and length of dislocation

d. None of these

121: Requirement for cross-slip movement of dislocation

A. Preferred slip plane

b. Preferred slip direction

c. No preferred slip planes

d. No Preferred slip direction

122: Beneficial property of foreign particles

a. Reduces density

b. Act as stress raisers

c. Obstructs dislocation motion

d. None of these

123: Each of the following solids shows the Frenkel defect except

a. ZnS

b. AgBr

c. AgI

d. KCl

124: A normal lattice site from where the atom or ion is missing, is known as

a. Schottky defect

b. Frenkel defect

c. Line defect

d. All of these

125: An atom located at a position that is not normal lattice site is called

a. Schottky defect

b. Frenkel defect

c. Exciton

d. Polaron

126: Quantized electron-hole pair is called

a. Exciton

b. Polaron

c. Colour centre

d. None of above

127: Diffusion constant depends upon

a. Nature of diffusing species

b. The Temperature

c. The medium in which it is diffusing

d. All of these

128: The band gap of ionic crystals is about 6eV which is equivalent to energy of a photon of wavelength

a. 2000A⁰

b. 1000A⁰

c. 3000A⁰

d. 5000A⁰

129: The process of diffusion is governed by

a. Diffusion coefficient

b. Einstein equation

c. Fick’s law

d. None of these

130: Atomic diffusion may take place by interstitial diffusion and

a. Dissociative diffusion

b. Ring diffusion

c. Vacancy diffusion

d. All

131: Ionic conductivity in alkali halides, like diffusion is explained in terms of migration of……

a. Negative

b. Positive

c. Both a and b

d. None of these

132: The fundamental mechanism by which atoms move through the crystal depends on

a. Crystal structure

b. Atomic size

c. Extent of defect in crystals

d. All

MCQ's with Answers

1: FCC lattice is the reciprocal lattice of the

2: The pure rotational symmetry which is not possible in crystalline solid is

3: The distance between the adjacent atomic planes in CaCO3 is 0.2nm. The smallest Bragg scattering for 0.03nm X-ray is

4: The number of two-dimensional lattices are

5: The structure factors for (010) and (200) reflections respectively, in face centred cubic lattice are

6: Packing fraction of an FCC lattice is

7: The number of lattice points in a primitive cell is

9: The volume of primitive cell of the FCC reciprocal lattice is

11: The De-Broglie wavelength associated with an electron of mass m and accelerated by a potential V is

12: Crystal structure consists of

13: Packing density is maximum for

14: Packing fraction is minimum for

15: Primitive cell has

16: Packing density of Diamond crystal is

17: NaCl crystal has……. structure

18: Miller Indices of a plane having intercepts 2,2, are

19: Number of atoms per unit cell in lattice are

20: Coordination number of fcc lattice is

21: Packing density of bcc lattice is

22: Cubic crystal is defined by

23: A crystal cannot have …………fold symmetry

24: A polyhedral block which fill whole of space by action of some suitable translation operation is called

25: The process in which solid grows is the key whether a solid is

26: Regular and periodic arrangement of atoms /molecules/ions in solid is due to tendency of them to settle down in state of

27: Rectangular primitive lattice is invariant under

28: Tetragonal lattice has………. Fold symmetry

29: A solid showing neither rectangular nor granular is known as

30: Inversion is ………symmetry

31: The vacant interstitial space between the close packed atoms is called

32: The maximum energy that X-ray photon can have cannot exceed maximum energy of

33: The shortest wavelength that is present in X-rays produced at an accelerating potential of 50kV is

34: Mosley plotted a graph between atomic number of elements and square root of frequencies of characteristic X-rays, which was

35:When X-rays are passed through a material , the intensity of transmitted beam is ……….that of incident beam

36: Bragg’s equation is a consequence of

37: A crystal lattice may be considered as an assembly of various different sets of equidistant………..planes

38: The 1st Brillion zone of a bcc lattice is a twelve faced solid called rhombic

41: Reciprocal of a reciprocal lattice is …………..lattice

42: Volume of a unit cell of reciprocal lattice is inversely proportional to that of corresponding

43: The 1st Brillion zone of a fcc lattice is a fourteen faced solid called truncated

44: The atomic scattering factor is a measure of ………..an atom in scattering X-rays

45: The Powder method is the most convenient method for obtaining diffraction data and is readily applicable to all

46: Neutron diffraction differs from X-ray diffraction in sense of that X-rays are scattered by electron clouds whereas neutrons are scattered by

47: Except of ………….all the metals are solid

48: Non-metals are

49: In diamond, bonding occurs in geometry

50: The ratio of ionic radii is denoted by

51: The compressibility K is defined as

52: The stiffness constant S’ s has the dimensions of

53: The compliance constant C’ s has the dimensions of

55: The ionic radius of Al+3 is

56: Both O-2 and Mg+2 has 10 electrons, but they don’t have the same

58: The Leonard-Jones potential is a function of

59: As the separation distance decreases below equilibrium, then the potential energy becomes

60: Cohesive energy is generally expressed in

61: The attractive and repulsive forces are balance each other when

62: Equilibrium density r0 of solid noble gases is

63: Equilibrium cohesive energy µ(ro) of solid noble gases is

64: The Madelung constant M is defined as

65: The value of Madelung constant is

67: Madelung constant for one dimensional ionic crystal is

69: NaCl is a ……….molecule

70: The lowest melting point is found in crystalline solid having……bonds

71: Which statement is correct?

72: In metallic bonds

73: Metals can exist in ….state only because there are forces of attraction acting between atoms when they are brought close to each other

74: Vander Waal bonding is …….of all bonding

75: The cohesive energy of ionic crystals is mainly due to

76: Carbon in the form of diamond, CCl4, CH4 etc. exhibit……covalent bonding

77: Covalently bonded atoms often produce a configuration that behaves like an

78: An atom without its valence electrons is called

79: The longitudinal stiffness C is defined as

81: Under what condition, dispersion effect is negligible and medium behaves like a homogeneous continuous?

82: The ratio of amplitude at K=0, for the acoustical branch is

83: At the zone boundary, the frequency of acoustical branch depends upon

84: If the crystal structure is unstable, then will be

86: The number of vector N is … operator

89: The Dulong-Petit law fails near room temperature (300 K) for manu light elements because their Debye temperature is:

90: According to Dulong-Petit law, the specific heat of a solid

91: The specific heat due to free electrons in metal varies as

3: The distance between the adjacent atomic planes in CaCO₃ is 0.2nm. The smallest Bragg scattering for 0.03nm X-ray is

**20: Coordination number of f_cc lattice is**

38: The 1^st Brillion zone of a bcc lattice is a twelve faced solid called rhombic

**43: The 1^st Brillion zone of a f_cc lattice is a fourteen faced solid called truncated**

55: The ionic radius of Al⁺³ is

56: Both O^-2 and Mg⁺² has 10 electrons, but they don’t have the same

62: Equilibrium density r₀ of solid noble gases is

63: Equilibrium cohesive energy µ(r_o) of solid noble gases is

76: Carbon in the form of diamond, CCl_4,CH₄ etc. exhibit……covalent bonding

92: The lattice specific heat at constant volume C_V of a solid at lower temperature depends on temperature T as

97: Cuttoff wave vector K_D is defined as