Energy Band Theory and Electrical Properties of Matter

Valence band is-

The reverse of conductivity is-

Which of the following arrangements is correct on the basis of conductivity of materials?

The conduction band and valence band in semiconductors are separated by energy gap of-

The laptop PC's modern electronic watches and calculators use the following for display:

If the lattice constant of this semiconductor is decreased, then which of the following is correct?

Carbon, Silicon and Germanium atoms have four valence electrons each. Their valence and conduction bonds are separated by energy band gaps represented by ${\left(E_{\mathrm{g}}\right)}_{\mathrm{c}}, {\left(E_{\mathrm{g}}\right)}_{\mathrm{st}}$ and ${\left(E_{\mathrm{g}}\right)}_{\mathrm{Ge}}$, respectively. Which one of the following relationships is true on their case?

Value of forbidden energy gap for semiconductor is:

The energy band gap of gallium arsenide phosphate is $1.98 e\mathrm{V}$. Calculate the wavelength of electromagnetic radiation emitted (in Angstrom), when electrons and holes combine in this alloy semiconductor directly. (Take Planck's constant $\left(h\right)=6.62\times {10}^{-34 }\mathrm{J} \mathrm{s}$)

The forbidden gap in the energy bands of germanium at room temperature is about 

If the energy of a photon of sodium light $(\mathrm{\lambda }=589 \mathrm{n}\mathrm{m})$ is equal to the bandgap of a semiconductor, calculate the minimum energy required to create hole-electron pair. Take, $h=6.6\times {10}^{-34} \mathrm{J} \mathrm{s}, c=3\times {10}^8 \mathrm{m} {\mathrm{s}}^{-1}$.

Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?

When the electrical conductivity of a semi-conductor is due to the breaking of its covalent bonds, then the semiconductor is said to be

The forbidden energy band gap in conductors semiconductor and insulators are $E_{g_1}, E_{g_2}$ and $E_{g_3}$ respectively. The relations among them is

A $p$-$n$ photodiode is made of a material with a band gap of $0.2 \mathrm{eV}$. The minimum frequency of the radiation that can be absorbed by the material is nearly:

Three photo diode $D_1, D_2$ and $D_3$ are made of semiconductors having a bandgap of $2 \mathrm{eV}, 2.5 \mathrm{eV}$  and $3 \mathrm{eV}$ respectively. Which one will be able to detect light of wavelength $4800 \mathrm{\AA }?$

In a conductor, the energy gap between conduction bands and valence bands is

While comparing a compound semiconductor with an elemental semiconductor, which of the following statement is not correct?

Which of the following is not a compound semiconductor?

Elemental semiconductors are :