The diffraction of barium with X-radiation of wavelength 2.29Å gives a first – order reflection at 30°. What is the distance between the diffracted planes.

(1) 3.29 Å

(2) 4.39 Å

(3) 2.29 Å

(4) 6.29 Å

When an electron in an excited Mo atom falls from L to the K shell, an X-ray is emitted. These X-rays are diffracted at angle of $7{.75}^o$ by planes with a separation of 2.64Å. What is the difference in energy between K-shell and L-shell in Mo assuming a first-order diffraction. $(\sin 7{.75}^o=0.1349)$

(1) 36.88 $\times {10}^{-15}J$

(2) $27.88\times {10}^{-16}J$

(3) 63.88 $\times {10}^{-17}J$

(4) $64.88\times {10}^{-16}J$

Which is the incorrect statement?

(1) _{${\mathrm{Fe}}_{0.95}\mathrm{O}$} has non-stoichiometric metal deficiency defect

(2) Density decreases in case of crystals with Schottky's defect

(3) NaCI(s) is insulator, silicon is semiconductor, silver is conductor, quartz is piezoelectric crystal

(4) Frenkel defect is favoured in those ionic compounds in which sizes of cation and anions are almost equal

In calcium fluoride, having the fluorite structure, the coordination numbers for calcium ion (Ca²⁺) and fluoride ion (F^-) are

(1) 4 and 2                   

(2) 6 and 6

(3) 8 and 4                   

(4) 4 and 8

Lithium has a bcc structure. Its density is 530 kg m^-3 and its atomic mass is 6.94 gmol^-1.

The edge length of a unit cell of lithium metal is -

(N_A=6.02 x10²³ mol^-1)

1. 352 pm

2. 527 pm

3. 264 pm

4. 154 pm

The ionic radii of A⁺ and B^- ions are 0.98 x 10^-10 m and 1.81 x10^-10 m.  The coordination

number of each ion in AB is.

1. 4

2. 8

3. 2

4. 6

The correct statement regarding defects in the crystalline solid is

1. Schottky defects have no effect on the density of crystalline solids

2. Frenkel defects decreases the density of crystalline solids

3. Frenkel defcct is a dislocation defect

4. Frenkel defect is found in halides of alkaline metals

The vacant space in bcc lattice cell is ;

1. 26%

2. 48%

3. 23%

4. 32%

if a is the length of the side of a cube, the distance between the body centered atom and

one corner atom in the cube will be :-

1. $\frac{2}{\sqrt{3}}a$

2. $\frac{4}{\sqrt{3}}a$

3. $\frac{\sqrt{3}}{4}a$

4. $\frac{\sqrt{3}}{2}a$

Copper crystallises in a face-centred cubic lattice with a unit cell length of 361 pm. What

is the radius of copper atom in pm?

1. 128

2. 157

3. 181

4. 108