Which of the following is true about the value of refractive index of quartz glass?
(A) Same in all directions
(B) Different in different directions
(C) Cannot be measured
(D) Always zero
Which of the following statements is not true about the hexagonal close packing?
(A) The coordination number is 12.
(B) It has 74% packing efficiency.
(C) Tetrahedral voids of the second layer are covered by the spheres of the third layer.
(D) In this arrangement spheres of the fourth layer are exactly aligned with those of the first layer.
Which stoichiometric defect does not change the density of the crystal?
(A) Frenkel defect
(B) Schottky defect
(C) Interstitial defect
(D) F-centres
A compound is formed by two elements M and N. The element N forms ccp lattice and atoms of M occupy two atoms an Mercury 1/3rd of tetrahedral voids. What is the formula of the compound?
(A) \(MN_2\)
(B) \(M_2\)\(N_3\)
(C) \(M_3\)\(N_2\)
(D) \(M_2\)\(N_2\)
Graphite cannot be classified as __________.
(A) Conducting solid
(B) Network solid
(C) Covalent solid
(D) Ionic solid
Silver crystallises in f.c.c. Lattice. It edge length of the unit cells is 4.07 × \(10^{–8}\) cm density and ism 10.5g \(cm^{–3}\). Calculate the atomic mass of silver.
(A) 144 g/mol
(B) 125 g/mol
(C) 106.6 g/mol
(D) 213 g/mol
Solid A is very hard electrical insulator in solid as well as in molten state and melts at an extremely high temperature. What type of solid is it?
(A) Ionic solid
(B) Molecular solid
(C) Covalent solid
(D) Metallic solid
The correct order of the packing efficiency in different types of unit cells is ________.
(A) fcc < bcc < simple cubic
(B) fcc > bcc > simple cubic
(C) fcc < bcc > simple cubic
(D) bcc < fcc = simple cubic
The sharp melting point of crystalline solids is due to ___________.
(A) a regular arrangement of constituent particles observed over a short distance in the crystal lattice.
(B) a regular arrangement of constituent particles observed over a long distance in the crystal lattice.
(C) same arrangement of constituent particles in different directions.
(D) different arrangements of constituent particles in different directions.
The total number of tetrahedral voids in the face centred unit cell is _____.
(A) 6
(B) 8
(C) 10
(D) 12
Which of the following conditions favours the existence of a substance in the solid state?
(A) High temperature
(B) Low temperature
(C) High thermal energy
(D) Weak cohesive forces
Which of the following is a network solid?
(A) (solid)
(B)
(C) Diamond
(D) (ice)
Which of the following is an amorphous solid?
(A) Graphite (G)
(B) Quartz glass (SiO2)
(C) Chrome alum
(D) Silicon carbide (SiC)
Which of the following is not true about the ionic solids?
(A) Bigger ions form the close packed structure.
(B) Smaller ions occupy either the tetrahedral or the octahedral voids depending upon their size.
(C) Occupation of all the voids is not necessary.
(D) The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids.
Which of the following statements is not true about amorphous solids?
(A) On heating they may become crystalline at certain temperature.
(B) They may become crystalline on keeping for long time.
(C) Amorphous solids can be moulded by heating.
(D) They are anisotropic in nature.