Zn convert it's melted state to its solid state, it has HCP structure, then number of nearest atom is : -
  •    6
  •    8
  •   12
  •   4

The term "amorphous solid" means -

  •  solids whose constituent particles are of irregular shapes and have short-range order

  •  solids that are isotropic in nature and melt over a range of temperature

  • pseudo solids or super cooled liquids that do not have definite heat of fusion

  • all of above

The physical characteristic of glass is different from solid-like quartz. The reason is-

  • In the glass, particles have short-range order, in quartz, the particles have long-range orders.

  • In the glass, particles have long-range order, in quartz, the particles have short-range orders.

  • In the glass, particles have short-range order, in quartz, the particles have both long-range and short-range orders.

  • In the glass, the particles have long-range order, in quartz, the particles have both long-range and short-range orders. 

 The pair having only molecular solids among the following is -

  •  Brass and SiC

  •  Ammonium phosphate (NH4)3PO4

  •  SiC and plastic 

  •  Tetra phosphorus decaoxide (P4O10) and I2

In a cubic close-packed structure, the coordination number of atoms is -

  •   12

  •   8

  •   1

  •   4

The number of lattice points in one unit cell of face-centred tetragonal lattice is  -

  • 4 

  • 12

  • 14 

  • 9

The similarity between metallic and ionic crystals is -

  • Both these crystal types are held by the electrostatic force of attraction.

  • Both these crystal types are held by the Van der Waal's forces of attraction.

  • Both these crystal types are held by  hydrogen bonding .

  • Both these crystal types are held by covalent bonding.

A cubic solid is made of two elements P and Q. Atoms of Q occupy the corners of the cube and P occupy the body centre. The formula of this compound and the coordination number of Q are respectively - 

  • PQ, 8

  • P2Q, 8

  • P2Q2, 8

  • PQ, 12

Niobium crystallizes in body-centred cubic structure. If the density is 8.55 g cm−3, the atomic radius of niobium(atomic mass 93 u) is -

  • 13.32 nm

  • 12.32 nm

  • 14.32 nm

  • 15.32 nm

If the radius of the octahedral void is r and the radius of the atoms in close packing is R, the relation between r and R would be -

  • r = 0.444R

  • r = 1.414R

  • r = 0.114R

  • r = 0.414R

Higher conductivity of p-type and n-type semiconductors is due to :

  • Increase in the number of positive holes and mobile electrons respectively  .

  • Increase in the number of electrons in both types of semiconductors.

  • Increase in the number of positive-holes in both types of semiconductors.

  • None of the above.

(i) Ge is doped with In

(ii) Si is doped with B. 

The semiconductors formed in the above cases are :

  • (i) n-type semiconductor  (ii) p-type semiconductor .

  • (i) p-type semiconductor  (ii) n-type semiconductor .

  • p-type semiconductor in both the cases.

  • n-type semiconductor in both the cases.

Aluminum crystallizes in a cubic close-packed structure. It's metallic radius is 125 pm. The number of unit cells in 1.00 cm3 of aluminum are : 

  • 2.27 x 1022

  • 354 x 1022

  • 4.54 x 1022

  • 127 x 1020

NaCl is doped with 10−3 mol % of SrCl2, the number of cation vacancies post doping would be -

  • 4.022 × 108

  • 5.022 × 1018

  • 6.022 × 1018

  • 7.022 × 108

In a body-centred cubic structure, the coordination number of atoms is

 

  •   12

  •   8

  •   1

  •   4

The relation between the atomic mass of unknown metal with density and the dimension of its unit cell is given by  :

(Given: All the cell edge lengths are equal)

  •  m = ρ a3NAZ

  •  m = ρ NA a3 Z

  • 3. m = Zρ NA a3

  •  m = Z NAa3 ρ

The correct statement among the following  is:

  • Semiconductors have a small energy gap between the valence band and the conduction band.

  • Conductors have overlapped valence band and conduction band.

  • Insulators have a large energy gap between the valence band and conduction band.

  • All of the above.

A defect that has an equal number of missing cations and anions is:

  • Schottky defect.

  • Frenkel defect.

  • Both (1) and (2)

  • None of the above.

The magnetic substances that have lesser magnetic moment than expected is known as -

  • Paramagnetic.

  • Ferrimagnetic.

  • Antiferromagnetic.

  • None of the above.

The number of tetrahedral and octahedral voids in hexagonal primitive unit cell are repectively:

  • 2, 1

  • 12, 6

  • 8, 4

  • 6, 12

Solids have a definite volume because of : 
  • Strong intermolecular forces.
  • Weak intermolecular forces.
  • Weak intramolecular forces.
  • All of the above.
The contribution (per unit cell) of an atom located at (i) corner and (ii) body-centre of a cubic unit cell respectively is :
  • 8 , 1
  • 1/8 , 1
  • 1/2 , 1/4
  • 1/4 , 1
Statement 1:  ZnS shows Frenkel defect.
Statement 2: AgBr shows Frenkel as well as Schottky defect.
  • Statement 1 is true , statement 2 is false.
  •  Statement 1 is false , statement 2 is true.
  • Both statements are true.
  • Both statements are false.
When a cation of higher valency is added as an impurity in an ionic solid, then : 
  • Vacancies are created .
  • Stoichiometry remains unaffected.
  • Excess of metal ions is created.
  • Both (2) and (3) 

A group 14 element is converted into n-type semiconductor by doping it with : 
 
  •  Boron 
  • Aluminium
  • Phosphorous
  • All of the above.
Substances used for making permanent magnets are :
 
  • Ferrimagnetic
  • Ferromagnetic
  • Antiferromagnetic 
  • Both (1) and (3) 
Liquids and gases are categorised as fluids because of :
  • Tendency to liquefy.
  • Free electrons.
  • Tendency to flow.
  • Strong forces of attraction.
Solids are incompressible because :
 
  • Distance between constituent particles is very less.
  • Forces of attraction between constituent particles are weak. 
  •  Distance between constituent particles is high.
  • They have low melting points.
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