Are the $n$ -type and $p$ -type materials electrically neutral? Explain.

Name the charge carriers in the following at room temperature.

$\left(\mathrm{i}\right)$ conductors

Name the charge carriers in the following at room temperature.

$\left(\mathrm{ii}\right)$ intrinsic semiconductors

Name the charge carriers in the following at room temperature.

$\left(\mathrm{iii}\right)$ insulators. 

How does the resistance of a semiconductor change with rise of temperature ?