Questions in semiconductor

Select	Question
	The valence of an impurity added to germanium crystal in order to convert it into a P-type semi conductor is
	In a semiconductor, the concentration of electrons is $8\times {{10}^{14}}/c{{m}^{3}}$and that of the holes is $5\times {{10}^{12}}c{{m}^{3}}.$ The semiconductor is
	In P-type semiconductor, there is
	The valence of the impurity atom that is to be added to germanium crystal so as to make it a N-type semiconductor, is
	Silicon is a semiconductor. If a small amount of As is added to it, then its electrical conductivity
	When the electrical conductivity of a semi- conductor is due to the breaking of its covalent bonds, then the semiconductor is said to be
	A piece of copper and the other of germanium are cooled from the room temperature to 80 K, then which of the following would be a correct statement
	To obtain P-type $Si$ semiconductor, we need to dope pure $Si$ with
	Electrical conductivity of a semiconductor
	Three semi-conductors are arranged in the increasing order of their energy gap as follows. The correct arrangement is