In the energy band diagram of insulators,the band gap and the conduction band are respectively:

In a semiconducting material,the mobilities of electrons and holes are $\mu_e$ and $\mu_h$ respectively. Which of the following is true?

What is the maximum wavelength of electromagnetic radiation that can create an electron-hole pair in a material with a band gap of $0.7 \ eV$? (Planck's constant $h = 4.136 \times 10^{-15} \ eV \cdot s$, velocity of light $c = 3 \times 10^8 \ m/s$).

The energy gap of silicon is $1.1 \, eV$. At what wavelength will silicon stop absorbing photons? (in $\mathring A$)

When the temperature of a semiconductor is increased,its resistance and electric conductivity respectively.

$A$ solid which is not transparent to visible light and whose conductivity increases with temperature is formed by