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

1. At ordinary temperatures, the resistance of a metallic conductor generally increases when temperature rises mainly because:

2. A two-input gate has inputs and . Its output is:

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

The nearly flat part of the graph represents:

4. Avalanche breakdown is more commonly associated with:

5. A -only realization is preferred in a digital integrated circuit because:

6. A doped silicon bar has length , cross-sectional area , and conductivity . Its resistance is:

7. Consider the following statements about -type and -type semiconductors.
I. -type semiconductors are produced using donor impurities.
II. -type semiconductors are produced using acceptor impurities.
III. A doped semiconductor must be electrically charged overall.
The valid statements are:

8. A diode has its cathode at and its anode at . The bias condition is:

9. In a bridge rectifier, two diodes conduct in each half-cycle. If each conducting diode has a forward drop of , the total diode drop in the conducting path is:

10. A two-input gate has inputs and . Its output is:

11. In the band picture of an -type semiconductor, the donor level is usually located:

12. The reason and gates are called universal gates is that:

13. Use the graph description below.

The higher position of a curve for larger shows that:

14. A Zener regulator has , , and . The Zener must carry at least to regulate. The maximum load current for regulation is:

15. The statement “an intrinsic semiconductor conducts only by electrons” is incomplete because:

16. The base of a transistor is made thin and lightly doped mainly so that:

17. A comparison table for rectifiers is shown below.

The row that is not suitable is:

18. Study the truth table.

The logic gate represented is:

19. A common-emitter amplifier has . A small input signal causes to decrease by . The collector voltage change is:

20. A transistor has and . The base current is:

21. A student compares three Fermi-level positions.

The most suitable classification is:

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

23. A switching transistor has , load resistance , and negligible saturated collector-emitter voltage. The collector current in saturation is approximately:

24. A logic circuit gives . If , , and , then is:

25. Use the circuit description below.

The final output is:

26. A graph of resistance versus temperature is drawn for a semiconductor over a moderate temperature range. The expected qualitative shape is:

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

28. A half-wave rectifier uses a single diode with a load resistor. Its diode conducts during:

29. A claim says: “In the active region, the collector-base junction is reverse biased, so no carrier can cross into the collector.” The claim is:

30. In reverse bias, the effective barrier potential of a - junction:

31. The Boolean expression for a two-input gate is:

32. A bipolar junction transistor is called “bipolar” because its operation involves:

33. A transistor has two - junctions because:

34. Holes diffuse from the -side to the -side in a newly formed junction. The conventional current due to this hole diffusion is:

35. A semiconductor device has -- regions, an inward emitter arrow, emitter-base junction forward biased, and collector-base junction reverse biased. It is:

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

37. The truth table below belongs to which two-input gate?

38. Assertion: A semiconductor can become more conducting when some electrons receive enough thermal energy to cross the forbidden gap.
Reason: Electrons in the conduction band can take part in electrical conduction.

39. A two-input gate gives output only when both inputs are , and gives output for all other input combinations. The gate is:

40. In a - junction at equilibrium, diffusion and drift are both present. The net current is zero because:

41. A device system needs output only when neither input nor input is . The suitable gate is:

42. A full-wave rectifier is connected to an input of frequency . The time interval between successive output pulses is:

43. A transistor has and emitter current . The collector current and base current are:

44. A circuit designer wants an output only when a light sensor signal and an enable signal . The sensor output is from a photodiode circuit, and the final switching device is a transistor. The suitable logic relation and transistor state for are:

45. A semiconductor bar has electron concentration larger on the left side than on the right side, with no external electric field applied. The initial electron diffusion is mainly:

46. A silicon diode has a built-in barrier of about . If a forward bias of is applied, the effective barrier is approximately:

47. Electron-hole recombination in a semiconductor means that:

48. A transistor with is required to switch a collector current. The base current estimated from active-region gain is:

49. In a transistor configuration, the input is applied between the emitter and base, and the output is taken between the collector and base. The terminal common to both input and output circuits is the base. This configuration is:

50. A transistor has and . The values of and are closest to: