Question

$\left(i\right)$ What happens to the resistivity of semi-conductors with the increase of temperature?
$\left(ii\right)$ For a fuse, higher the current rating ________ is the fuse wire. (Thicker / Thinner)

Answer 1

$\left(i\right)$ The resistivity of semi-conductor decreases with the increase in temperature. It is because the charge carriers in the semiconductors increase flowing with more ease in semiconductors due to rise in temperature.
$\left(ii\right)$ For a fuse, higher the current rating thicker is the fuse wire. High current rating means the fuse has a lower resistance. The cross-sectional area (i.e. thickness) of the fuse wire must be higher.