Donor type impurity is found in 
(1) Trivalent elements       

(2) Pentavalent elements

(3) In both the above       

(4) None of these

The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the 

(1) Variation of scattering mechanism with temperature

(2) Crystal structure

(3) Variation of the number of charge carriers with temperature

(4) Type of bond

The charge on a hole is equal to the charge of

(1) Zero               

(2) Proton

(3) Neutron         

(4) Electron

Which of the following has negative temperature coefficient of resistance 
(1) Copper               

(2) Aluminium

(3) Iron                   

(4) Germanium

In semiconductors at a room temperature 

(1) The valence band is partially empty and the conduction band is partially filled

(2) The valence band is completely filled and the conduction band is partially filled

(3) The valence band is completely filled

(4) The conduction band is completely empty

Regarding a semiconductor which one of the following is wrong 

(1) There are no free electrons at room temperature

(2) There are no free electrons at 0 K

(3) The number of free electrons increases with rise of temperature

(4) The charge carriers are electrons and holes

Which of the following statements is true for an N-type semi-conductor 

(1) The donor level lies closely below the bottom of the conduction band

(2) The donor level lies closely above the top of the valence band

(3) The donor level lies at the halfway mark of the forbidden energy gap

(4) None of above

Choose the correct statement

(1) When we heat a semiconductor its resistance increases

(2) When we heat a semiconductor its resistance decreases

(3) When we cool a semiconductor to 0 K then it becomes super conductor

(4) Resistance of a semiconductor is independent of temperature

Intrinsic semiconductor is electrically neutral. Extrinsic semiconductor having large number of current carriers would be 

(1) Positively charged

(2) Negatively charged

(3) Positively charged or negatively charged depending upon the type of impurity that has been added

(4) Electrically neutral