Question

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

(a) ionic bonding

(b) covalent bonding

(c) van der-Waals' bonding

(d) metallic bonding

Answer 1

Correct Option (b) covalent bonding

Explanation:

Covalent bonding.

[they are simply semiconductors having 4th group]