An intrinsic semiconductor has `5 xx 10^(28)` atoms and the carrier concentration `

An intrinsic semiconductor has `5 xx 10^(28)` atoms and the carrier concentration `1.5 xx 10^(16)` .If it is doped by a pentavaIent impurity in the ratio `1:10^(6)` , then caIcuIate number density of hoIes as charge carriers.