The state of the energy gained by valence electrons when the temperature is raised or when an electric field is applied is called as:

This question has Statement $1$ and Statement $2$. Of the four choices given after the Statements,choose the one that best describes the two Statements.
Statement $1$ : $A$ pure semiconductor has a negative temperature coefficient of resistance.
Statement $2$ : On raising the temperature,more charge carriers are released into the conduction band.

At ordinary temperatures, the electrical conductivity of semiconductors in $S/m$ (or $mho/m$) is in the range:

When radiation with a wavelength shorter than $2480 \, nm$ is incident on a semiconductor,its conductivity increases. The bandgap of this semiconductor is ....... $eV$.

In semiconductors at room temperature,

How does an intrinsic semiconductor behave at $0 \ K$?