Solid State

Work function,  ${?}_0=6.63\times 10^{-19}J$

Threshold wavelength ${\lambda }_0=?$

Using ; ${?}_0=\frac{hc}{{\lambda }_0}$

${\lambda }_0=\frac{hc}{{?}_0}$

= 300 × 109 m = 300 nm

1.38 Kindly consider the following

17. Option (ii) Quartz glass (SiO₂) is correct since quartz glass (SiO₂)is amorphous in nature as there is no long range ordered arrangement of the constituent particles being present in it and hence it is an amorphous solid.

Ferromagnetism: The substances that are strongly attracted by a magnetic field are called ferromagnetic substances can be permanently magnetised even in the absence of a magnetic field. Some examples of ferromagnetic substances are iron, cobalt, nickel, gadolinium, and CrO₂. In solid state, the meta

1.49 NaCl is doped with 10⁻³ mol % of SrCl₂

100 moles of NaCl are doped with 0.001 moles of SrCl₂

1.48 It is given that aluminum crystallises in a cubic closed packed structure.
Its metallic radius is 125 pm.

For cubic close-packed structure

a=2√2r=2√2×125=354 pm

Here, a is the edge length of the unit cell and r is the atomic radius.

(ii) Volume of one unit cell = a³ =(354 pm)³=4.4×10⁻²³cm³(1 pm=10⁻¹

Schottky defect: Schottky defect is basically a vacancy defect shown by ionic solids. In this defect, an equal number of cations and anions are missing to maintain electrical neutrality. It decreases the density of a substance. Significant number of Schottky defects is present in ionic solids. For e

1.47 The energy gap between the valence band and conduction band in an insulator is very large while in a conductor, the energy gap is very small or there is overlapping between valence band and conduction band.
(ii) In a conductor, the valence band is practically filled or there is overlapping betw

1.45 For fcc unit cell, a=2√2?.

Here, a is the edge length and r is the atomic radius (0.144 nm).

a = 2√2 ×0.144 = 0.407 nm

Hence, the length of a side of a cell is 0.407 nm.

1.44 Ge is group 14 element and In is group 13 element. Hence an electron deficient hole is created and therefore, it is p–type.
2. B is group 13 elements and Si is group 14 elements, there will be a free electron. Hence, it is n-type