22. In a p − n junction ___ ?

21. The intrinsic semiconductor becomes an insulator at ___ ?

20. An alternating current can be converted into direct current by a ____ ?

19. In forward bias, the width of potential barrier in a p − n junction diode _____ ?

18. A depletion layer consists of ?

17. Which of the following when added acts as an impurity into silicon produced n-type semiconductor ?

16. In a junction diode, the holes are due to ?

15. A semi-conducting device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to almost zero. The device may be ?

14. The cause of the potential barrier in a p − n diode is ?

13. To obtain a p-type germanium semiconductor, it must be doped with ?

12. When arsenic is added as an impurity to silicon, the resulting material is ?

11. Which of the following, when added as an impurity, into the silicon, produces n-type semiconductor ?