In semiconductors at room temperature,

Assertion: If the temperature of a semiconductor is increased,then its resistance decreases.
Reason: The energy gap between the conduction band and the valence band is very small.

$\sigma_1$ and $\sigma_2$ are the electrical conductivities of $Ge$ and $Na$ respectively. If these substances are heated,then

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.

The expected energy of the electrons at absolute zero is called

The energy of a photon of sodium light $(\lambda = 589 nm)$ is equal to the band gap of a semiconductor material. Find the value of $E/kT$ at $300 K$.