The process of adding impurities to the pure semiconductor is called 
(1) Drouping       

(2) Drooping

(3) Doping           

(4) None of these

The energy band gap is maximum in

(1) Metals               

(2) Superconductors

(3) Insulators         

(4) Semiconductors

To obtain electrons as majority charge carriers in a semiconductor, the impurity mixed is 
(1) Monovalent         

(2) Divalent

(3) Trivalent               

(4) Pentavalent

Which is the correct relation for the forbidden energy gap in the conductor, semiconductor, and insulator

(1) $∆{\mathrm{Eg}}_{\mathrm{c}}<∆{\mathrm{Eg}}_{\mathrm{insulator}}<∆{\mathrm{Eg}}_{sc}$

(2) $∆{\mathrm{Eg}}_{\mathrm{c}}<∆{\mathrm{Eg}}_{\mathrm{sc}}<∆{\mathrm{Eg}}_{\mathrm{insulator}}$

(3) $∆∆{\mathrm{Eg}}_{\mathrm{sc}}<∆{\mathrm{Eg}}_{\mathrm{insulator}}<{\mathrm{Eg}}_{\mathrm{c}}$

(4) $∆{\mathrm{Eg}}_{\mathrm{sc}}<∆Ec<∆{\mathrm{Eg}}_{\mathrm{insulator}}$

To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behave like

(1) A conductor

(2) A P-type semiconductor

(3) An N-type semiconductor

(4) An insulator

If ${\mathrm{n}}_{\mathrm{e}}$ and ${\mathrm{n}}_{\mathrm{h}}$ are the number of electrons and holes in a semiconductor heavily doped with phosphorus, then

(1) ${\mathrm{n}}_{\mathrm{e}}$>> ${\mathrm{n}}_{\mathrm{h}}$               

(2)  ${\mathrm{n}}_{\mathrm{e}}$<< ${\mathrm{n}}_{\mathrm{h}}$  

(3) ${\mathrm{n}}_{\mathrm{e}}$$\le$${\mathrm{n}}_{\mathrm{h}}$                 

(4) ${\mathrm{n}}_{\mathrm{e}}$ = ${\mathrm{n}}_{\mathrm{h}}$  

At room temperature, a P-type semiconductor has

(1) Large number of holes and few electrons

(2) Large number of free electrons and few holes

(3) Equal number of free electrons and holes

(4) No electrons or holes

For germanium crystal, the forbidden energy gap in joules is

(1) $1.12\times {10}^{-19}$        

(2) $1.76\times {10}^{-19}$

(3)  $1.6\times {10}^{-19}$         

(4) Zero

A pure semiconductor behaves slightly as a conductor at

(1) Room temperature             

(2) Low temperature

(3) High temperature               

(4) Both (b) and (c)