The phenomenon in which polar crystals on heating produce electricity is called:-

1. Pyro-electricity.
2. Piezo-electricity.
3. Ferro-electricity.
4. Ferri-electricity.

Total volume of atoms present in a face centred cubic unit cell of a metal is -

(r is atomic radius)

1. 20/3 $\pi$r³

2. 24/3 $\pi$r³

3. 12/3 $\pi$r³

4. 16/3 $\pi$r³

Lithium borohydride (LiBH₄), crystallizes in an orthorhombic system with 4 molecules per unit cell. The unit cell dimensions are:- a = 6.81 Å , b = 4.43 Å, c = 7.17 Å. If the molar mass of LiBH₄ is 21.76 g mol^-1, then the density of the crystal is:-

1. 0.67 g cm^-3

2. 0.58 g cm^-3

3. 1.23 g cm^-3

4. None of the above.

A solid has a bcc structure. If the distance of closest approach between the two atoms is 1.73 Å, then the edge length of the cell is:

1. 200 pm

2. $\raisebox{1ex}{$\sqrt{3}$}\!\left/ \!\raisebox{-1ex}{$\sqrt{2}$}\right.$ pm

3. 142.2 pm

4. $\sqrt{\mathrm{2 }}$pm

The anions (A) form hexagonal closest packing and atoms (C) occupy only 2/3 of octahedral voids in it. The general formula of the compound is-
1. CA
2. CA₂
3. C₂A₃
4. C₃A₂

The mass of a unit cell of CsCl corresponds to:-
1. 8Cs⁺ and Cl^-
2. 1Cs⁺ and 6Cl^-
3. 1Cs⁺ and 1Cl^-
4. 4Cs⁺ and Cl^-

In a compound, atoms of element Y form ccp lattice, and those of element X occupy 2/3^rd of tetrahedral voids. The formula of the compound will be :-
1. X₃Y₄
2. X₄Y₃ 
3. X₂Y₃
4. X₂Y

The density of KCl is 1.9893 g cm^-3 and the length of a side unit cell is 6.29082 Å as determined by X-ray diffraction. The value of Avogadro’s number calculated from this data is:-

1. 6.017 x 10²³

2. 6.023 x 10²²

3. 7.03 x 10²³

4. 6.01 x 10¹⁹

TiO₂ is a well-known example of:

1. Triclinic system.

2. Tetragonal system.

3. Monoclinic system.

4. None of the above.

Oxygen atoms form fcc unit cells with 'A' atoms occupying all tetrahedral voids and 'B' atoms occupying all octahedral voids. If atoms are removed from two of the body diagonals then the formula of the resultant compound formed is: 

1. A₄B₄O₇

2. A₈B₆O₇

3. A₈B₈O₇

4. A₆B₈O₆