The unit cell dimensions of a cubic lattice (edges a, b, c and the angles between them, α, β, γ) are : 

1. a = b = c, $\mathrm{\alpha }= \mathrm{\beta }= \mathrm{\gamma }= 90°$

2. a = b $\ne$c, $\mathrm{\alpha }= \mathrm{\beta }= \mathrm{\gamma }= 90°$

3. a = b = c, $\mathrm{\alpha }= \mathrm{\gamma }= 90°,$ $\mathrm{\beta }\ne 90°$

4. a $\ne$b $\ne$c, $\mathrm{\alpha }= \mathrm{\beta }= 90°,$ $\mathrm{\gamma }\ne 90°$

Copper metal has a face-centered cubic structure with the unit cell length equal to 0.361 nm. Picturing copper ions in contact along the face diagonal. The apparent radius of a copper ion is-

(A) 0.128                                         

(B) 1.42

(C) 3.22                                           

(D) 4.22

Choose the correct matching sequence from the possibilities given

A compound alloy of gold and copper crystallizes in a cube lattice in which the gold atoms occupy the lattice points at the corners of a cube and the copper atoms occupy the centres of each of the cube faces. The formula of this compound is-

(1) AuCu                                                   

(2) $AuC{u}_2$

(3) $AuC{u}_3$                                                 

(4) None of these 

1. a, b                                         

2. b, c

3. a, b, c                                     

4. a, c

Among the following types of voids, which one is the largest void-

(1) Triangular system                             

(2) Tetragonal system

(3) Monoclinic system                             

(4) Octahedral

Bragg’s equation is-

(1) $n\lambda =2\theta \sin \theta$                               

(2) $n\lambda =2d\sin \theta$

(3) $2n\lambda =d\sin \theta$                               

(4) $\lambda =\left(2d/n\right)\sin \theta$

The n of a cubic unit cell is 4. The type of cell as-

(1) Body centred                               

(2) Face centred

(3) Primitive                                     

(4) None of these

Close packing is maximum in the crystal which is-

(1) Simple cube                               

(2) bcc

(3) fcc                                             

(4) None

In a face centred cubic arrangement of metallic atoms, what is the relative ratio of the sizes of tetrahedral and octahedral voids ?

(1) 0.543                                   

(2) 0.732

(3) 0.414                                   

(4) 0.637