Semiconductor Electronics-Materials, Devices and Simple Circuits Mock Test – Class 12 Physics

1. A transistor has . The corresponding value of is closest to:

2. A common-emitter amplifier is biased at a proper operating point before applying the signal. The main reason is to:

3. The emitter of a bipolar junction transistor is usually heavily doped because its main role is to:

4. A semiconductor region has an electric field directed from left to right. The drift directions of electrons and holes are:

5. In a donor-doped semiconductor, the positive donor ions are called fixed ions because they:

6. A barrier potential of corresponds to an energy of for one electron because:

7. A practical circuit uses a bridge rectifier, capacitor filter, and Zener regulator before feeding a digital logic circuit. The most suitable purpose of this arrangement is:

8. A semiconductor sample has resistivity at one temperature and after heating. By what factor does its conductivity change?

9. The pair that contains two common elemental semiconductors is:

10. Study the table for transistor structure.

The row that is not suitable is:

11. Use the circuit description below.

The final output is:

12. Study the reverse-bias observations.

The row that is not suitable is:

13. A device system needs output only when both input conditions are satisfied. The suitable gate is:

14. For an intrinsic semiconductor, the conductivity relation may be written as:

15. The formation of allowed energy bands in a solid is closely connected with:

16. In another switching system, a warning light should turn on if either sensor or sensor detects a fault. The suitable logic gate is:

17. A diode terminal list mentions anode and cathode. In the usual - diode naming convention:

18. In the depletion region of a - junction, the charge on the -side close to the junction is mainly due to:

19. A full-wave bridge rectifier is supplied from a secondary with . Each conducting silicon diode drops . A capacitor charges approximately to the peak load voltage. The approximate capacitor voltage is:

20. A two-input logic gate has output only for and . Its Boolean expression is:

21. A transistor has , , and . If , the active-region estimate gives , but saturation current allowed by the load is:

22. A heavily doped - junction generally undergoes Zener breakdown at relatively low reverse voltage because:

23. In the - characteristic of a - junction diode, the usual graph is plotted with:

24. A pure semiconductor has thermally generated electron-hole pairs per cubic metre. The total number of mobile charge carriers per cubic metre is:

25. A diode in a circuit is intended to block current from a source. The anode is connected to , and the cathode is connected to . This arrangement blocks current mainly because:

26. A solar cell usually operates without external bias because:

27. A two-input gate is followed by a gate. The resulting combination behaves as:

28. Use the graph description below.

The most suitable interpretation is:

29. A graph is described for a reverse-biased diode.

The nearly flat part of the graph represents:

30. A common-emitter amplifier has voltage gain . If the input signal is peak, the output signal is:

31. An emits photons of energy . Taking , the approximate wavelength is:

32. A full-wave rectifier is supplied by an source of frequency . The frequency of the ripple pulses in the output is:

33. Read the circuit situation below.

What makes the load current unidirectional?

34. The depletion layer in an unbiased - junction remains stable mainly because:

35. A Boolean circuit has . For , , and , the output is:

36. A diode under reverse bias suddenly carries a very large current when the reverse voltage is made high enough. The most suitable description is:

37. A transistor switch has , load , and negligible . If the transistor is saturated, the collector current is:

38. A Zener regulator has , , , and . The Zener current is:

39. A silicon crystal contains one impurity atom for roughly every host atoms, and its conductivity changes noticeably. This is possible because:

40. Study the truth table.

The logic gate represented is:

41. A material has , is doped with phosphorus, and then joined with a boron-doped region to form a junction. The most suitable sequence of ideas is:

42. The depletion region opposes further majority-carrier diffusion mainly because:

43. In a pure silicon crystal, each silicon atom forms covalent bonds with neighbouring silicon atoms. This bonding is important because it:

44. A diode symbol is used in a circuit diagram. The terminal connected to the -type side is called the:

45. A diode has -side at and -side at . The diode is:

46. In a common-emitter configuration, the output is usually taken between:

47. A transistor amplifier receives a sinusoidal input, but the output waveform has flattened tops. The most likely reason is:

48. A light-emitting diode works mainly because:

49. A table compares discrete-component circuits and integrated circuits.

The row that is not suitable is:

50. Consider the following statements about reverse bias.
I. The -side is connected to the negative terminal.
II. The depletion region widens.
III. The reverse current before breakdown is mainly due to majority carriers.
The valid statements are: