JAMB - Physics (2009 - No. 35)
When a pentavalent impurity is added to a pure semiconductor, it becomes?
a p-type semiconductor
an n-type semiconductor
an insulator
an intrinsic semi-conductor
Paliwanag
When a pentavalent (5 outer electron)atom is added to a pure semiconductor, there is an extra electrons which does not take part in the covalent bonding resulting in an n-type semiconductor.