Solid state practice · Mixed difficulty

An element has bcc structure having unit cells $12.08 \times {10^{23}}$. The number of atoms in these cells is :

Which among the following will show anisotropy?

Assertion: Ferromagnetic compound is more attracted in magnetic field.

Reason: Because all electron are aligned in same direction.

Which of the following statements is not correct about hexagonal close packing?

The metal surfaces are excellent reflectors because of absorption and re-emission of light by :

If a crystal lattice of a compound, each corner of a cube is enjoyed by sodium, each edge of a cube has oxygen and centre of a cube is enjoyed by tungsten $(W)$, then give its formula

The radius of the $\mathrm{N}{\mathrm{a}^ + }$ is 95 pm and that of $\mathrm{C}{\mathrm{l}^ - }$ ion is 181 pm. Predict the co-ordination number of $\mathrm{N}{\mathrm{a}^ + }$:

A certain gas diffuses from two different vessels $A$ and $B$. The vessel $A$ has a circular orifice while vessel $B$ has square orifice of length equal to the radius of the orifice of vessel $A$. The ratio of the rates of diffusion of the gas from vessel $A$ to vessel $B$ assuming same temperature and pressure is:

The fraction of the total volume occupied by the atoms present in bcc unit cell is

At zero kelvin, most of the ionic crystals possess.

In a face centred cubic cell, an atom at the face centre is shared by :

The ratio of closed packed atoms to tetrahedral holes in cubic close packing is:

If Nacl is doped with $10^{-3} \,{~mol}_{\%} \,{GaCI}_3$, what is the concentration of the cation vacancies?

Which of the following statements is/are not true?

Given below are two statements.
Statement I: $\mathrm{O}_2, \mathrm{Cu}^{2+}$, and $\mathrm{Fe}^{3+}$ are weakly attracted by magnetic field and are magnetized in the same direction as magnetic field.
Statement II: $\mathrm{NaCl}$ and $\mathrm{H}_2 \mathrm{O}$ are weakly magnetized in opposite direction to magnetic field.
In the light of the above statements, choose the most appropriate answer from the options given below.

An example of a substance possessing giant covalent structure is

Solid $\mathrm{C}{\mathrm{O}_2}$ is an example of :

In ${A^ + }{B^ - }$ ionic compound, radii of ${A^ + }$ and ${B^ - }$ ions are 180 pm and 187 pm respectively. The crystal structure of this compound will be

A substance AB crystallizes in cubic
closest packing (C.C.P.) with B occupying
half the tetrahedral voids. One litre of
the crystal is doped with 1 mole atoms of
C some of which replace the B atoms
and remaining occupy few interstitial
voids without affecting the dimensions of
cubic crystal lattice. If density of crystal
before doping is 4.8 gm/millilitre and
density after doping is 4.795 gm /ml then
calculate % of C added with replace B
atoms.
(Given : Atomic weight : A, B
and C : 40, 30, 15)

The ratio of number of atoms present in a simple cubic, body centered cubic and face centered cubic structure are, respectively.

Which kind of defect is shown by the given crystal?
${K^ + }C{l^ - }{K^ + }C{l^ - }{K^ + }C{l^ - }$
$C{l^ - }{ \Box }\,C{l^ - }{K^ + }{ \Box }\,{K^ + }$
${K^ + }C{l^ - }\,{ \Box }\,C{l^ - }{K^ + }C{l^ - }$
$C{l^ - }{K^ + }C{l^ - }{K^ + }{ \Box }{K^ + }$

Of the elements $\mathrm{Sr},\mathrm{Zr},\mathrm{Mo},\mathrm{Cd}\,\mathrm{ and}\;\mathrm{ Sb},$ all of which are in $V$ period, the paramagnetics are:

$\mathrm{LiF}$ is a/an :

Piezoelectric substance of the following is

Which of the following is a covalent solid

The ionic radii of ${\mathrm{A}^\mathrm{ + }}\,\mathrm{and}\,{\mathrm{B}^\mathrm{ - }}$ ions are $0.98 \times {10^{ - 10}}m\,\mathrm{and}\,\,1.81 \times {10^{ - 10}}m.$ The coordination number of each ion in $AB$ is

Solids are characterised by their properties :

The vacant space in the bcc unit cell is

The correct statement in the following is

Liquid crystals are best used in: