Note

If you cannot find what you are looking for. Please visit our sitemap

Sunday, 19 June 2016

FSc ICS MCAT ECAT Physics Second Year Chapter 18 Electronics Choice Multiple Question (MCQ) Notes

FSc ICS MCAT ECAT Physics Second Year Chapter 18 Electronics Multiple Choice Question (MCQ) Notes

Both Bold and Underlined option is correct

1. The gate, which performs the operation of inversion is called:
  • NOT gate
  • AND gate
  • OR gate
  • XOR gate

2. The gate, which changes the logic level to its opposite level is called:
  • NOR gate
  • AND gate
  • OR gate
  • NOT gate

3. If both the inputs given to a gate are 1, such that the output is 0 then it is:
  • NAND gate
  • NOR gate
  • XOR gate
  • All of these

4. If both the inputs given to a gate are 0 such that the output is 1 then it is:
  • NAND gate
  • NOR gate
  • XNOR gate
  • All of these

5. XNOR gate can be made by combining:
  • OR, NOR, NOT gate
  • OR, AND, NOT gate
  • OR, NAND, NAND gate
  • NOR, AND, NOT gate

6. Breakdown voltage is:
  • 25 V
  • 15 V
  • 35 V
  • 5 V

7. The value of reverse current for Ge is:
  • 1 micro Ampere
  • 1 milli Ampere
  • 1 Ampere
  • 1 Mega Ampere

8. Device used for conversion of D.C. to A.C. is:
  • Oscillator
  • Rectifier
  • Amplifier
  • None

9. p-n junction when reversed biased acts as a:
  • Capacitor
  • On switch
  • Off switch
  • None

10. Pulsating D.C. can be made smooth by using a circuit known as:
  • Filter
  • Tank
  • Accepter
  • All

11. A photodiode can switch its current on Or off in:
  • nano second
  • milli second
  • micro second
  • centi second

12. Photodiode is used in:
  • Automatic switch
  • Optical communication equipment
  • Light meters
  • All

13. Current gain of a transistor which has collector current of 10 mA and a base current of 40 micro Ampere is:
  • 25
  • 250
  • 2500
  • 25000

14. In case of common emitter amplifier, phase difference between input and output:
  • 0 degree
  • 120 degree
  • 180 degree
  • 90 degree

15. When transistor acts as OFF switch then voltage across collector and emitter is _____ Vcc.
  • Less than
  • Greater than
  • Equal to
  • None

16. The photovoltaic cell is always:
  • Forward biased
  • Reverse biased
  • No biasing is required
  • None

17. Under ideal conditions, the collector current is:
  • Equal to base current
  • Nearly equal to emitter current
  • Less than base current
  • Always zero


18. One use of a single p-n junction semiconductor in an electrical circuit is a:
  • Rectifier
  • Transistor
  • Battery
  • Diode

19. The output from a full wave rectifier is:
  • An AC voltage
  • A DC voltage
  • Zero
  • A pulsating unidirectional voltage

20. When n-type semiconductor is heated:
  • Number of electrons increases while holes decreases
  • Number of holes increases while electrons decreases
  • Holes and electrons remains same
  • Holes and electrons increases equally

21. Zener diode is used for:
  • Rectification
  • Amplification
  • Stabilization
  • Modulation

22. In a semi-conducting diode, the reverse biased current is due to drift of free electrons and holes caused by:
  • Thermal excitations only
  • Impurity atoms only
  • Both first and second
  • Neither first nor second

23. In the reverse biased p-n junction, the current is of the order of:
  • Ampere
  • Milliampere
  • Microampere
  • Nanoampere

24. To measure light intensity we use:
  • LED with forward bias
  • LED with reverse bias
  • Photodiode with reverse bias
  • Photodiode with forward bias

25. On increasing the reverse bias to a large value in a p-n junction diode current:
  • Increases slowly
  • Remains fixed
  • Suddenly increases
  • Decreases slowly

26. Rectifier is used to convert:
  • Electrical energy to mechanical energy
  • Heat energy into electrical energy
  • High voltage into low voltage
  • AC into DC

27. In an n-p-n transistor p-type crystal acts as:
  • Emitter only
  • Base only
  • Collector only
  • Either emitter or collector

28. The emitter base junction in the transistor is:
  • Forward biased
  • Reverse biased
  • Either forward or reverse biased
  • Neither forward nor reverse biased

29. The current gain of common-base transistor amplifier is:
  • Less than one
  • More than one
  • Equal to one
  • Zero

30. In common-base transistor amplifier. the phase difference between output voltage and input voltage is:
  • Zero
  • 180 degree
  • 90 degree
  • 45 degree

31. For a common base transistor amplifier the numerical value is least for:
  • Voltage gain
  • Power gain
  • Resistance gain
  • Current gain

32. The base of the transistor is made thin and is doped with least impurity atoms, because:
  • About 95% charge carriers may cross
  • !00% charge carriers may cross
  • the transistor may be saved from high currents
  • None of these

33. A logic gate is an electronic circuit which:
  • Makes logic decisions
  • Allow electron flow only in one direction
  • Allows hole flow only in one direction
  • Alternates between 0 an 1 value


34. Digital circuits can be made by respective use of:
  • AND gates
  • OR gates
  • NOT gates
  • NAND gates

35. Which logic function has the output low only when inputs are high?
  • OR
  • NOR
  • AND
  • NAND

36. In a half wave rectifier the rms value of AC component of the waves:
  • Zero
  • Equal to DC value
  • More than DC value
  • Less than DC value

37. A PN junction has a thickness of the order of:
  • 10(-12) m
  • 10(-6) m
  • 1 mm
  • 1 cm

38. A hole in a p-type semi-conductor is:
  • A donor level
  • An excess electron
  • Missing electron
  • A missing atom

39. If PN junction is forward biased its resistance is:
  • Zero
  • Infinity
  • A few ohm
  • A few kilo ohms

40. A part of transistor which is heavily doped to produce large number of majority carriers is:
  • Emitter
  • Base
  • Collector
  • May be any one

41. How is emitter base junction in the transistor biased?
  • Forward
  • Reverse
  • May be forward or reverse
  • None

42. The potential barrier of silicon diode is:
  • 0.3 V
  • 0.5 V
  • 0.7 V
  • 0.9 V

43. If collector current is 10 mA and base current of 10 microA. What is the current gain of transistor?
  • 250
  • 500
  • 1000
  • None of these

44. An op-amplifier can be used as:
  • Inverting amplifier
  • Night switch
  • Comparator
  • All

45. The output of two input OR gate is zero only when:
  • Both are one
  • Both are zero
  • Either input is 1
  • None

46. The semi-conductor used for fast counting in electronic circuit is:
  • Photodiode
  • LED
  • Photovoltaic cell
  • Solar cell

47. For normal transistor operation Ie is given by:
  • Ie = Ic
  • Ie = Ic + Ib
  • Ie = Ib
  • None

48. The value of open loop gain value for the amplifier is:
  • Zero
  • Infinity
  • Very high
  • Very low

49. The gate will recognized the voltage as 1 if the applied voltage to gate is:
  • 1.5 V
  • 0.5 V
  • 3.5 V
  • 0.7 V

50. In the depletion region of an unbiased PN junction diode there are:
  • Only electrons
  • Only holes
  • Both holes and electrons
  • Ions

51. In a transistor, the conventional current flows from base to emitter. The transistor is:
  • NPN
  • PNP
  • FET
  • None of these

52. In full wave rectifier with input frequency 50 Hz the ripple in the output is mainly of frequency:
  • 25 Hz
  • 50 Hz
  • 100 Hz
  • Zero

53. What is the voltage gain in a common emitter amplifier where input resistance is 3 ohm and load resistance 24 ohm, β = 0.6?
  • 8.4
  • 4.8
  • 2.4
  • 480

54. How many NAND gates are used to form AND gate?
  • 1
  • 2
  • 3
  • 4

55. Photodiode operates when it is:
  • Forward biased
  • Reverse biased
  • Unbiased
  • None

56. The open loop gain of  op-amp is of the order of:
  • 10(3)
  • 10(4)
  • 10(5)
  • 10(6)

57. In  a forward biased p-n junction diode, current inside the junction diode is due to drift of:
  • Free electrons
  • Both types of majority carriers
  • Both types of minority carriers
  • Donor atoms

58. A p-n junction diode cannot be used for:
  • Rectification
  • Amplification
  • Obtaining light radiation
  • Detecting light intensity

59. In a semiconductor diode, p-side is earthed and to n-side is applied a potential of -2 volt; the diode shall:
  • Conduct
  • Not conduct
  • Conduct partially
  • Break down

60. In the symbol for a transistor, the arrow head points in the direction of flow of:
  • Holes 
  • Electrons
  • Majority carriers
  • Minority carriers

61. The current gain of common-emitter transistor amplifier is:
  • Less than one
  • More than one
  • Equal to one
  • Zero

62. In a common-emitter transistor amplifier, the phase difference between output voltage input voltage is:
  • Zero
  • 180 degree
  • 90 degree
  • 45 degree

63. The emitter of a transistor is doped the heaviest because it:
  • Acts as a supplier of charge carriers
  • Dissipates maximum power
  • has a large resistance
  • has a small resistance

64. At room temperature, potential difference develops across the depletion region in case of silicon:
  • 0.3 V
  • 0.7 V
  • 0.8 V
  • 0.9 V

65. Width of depletion region is:
  • 10(-8) m
  • 10(-7) m
  • 10(-6) m
  • 10(-4) m

66. In photovoltaic cell current is _______ proportional to intensity of light.
  • Directly
  • Inversely
  • Both first and second
  • None

67. Silicon transistors are preferred because:
  • High operating temperature
  • Low leakage current
  • Suited to high frequency circuits
  • All

68. If Rc = 10 kΩ , rie = 1kΩ β = 50 then gain of common emitter amplifier:
  • 500
  • 50
  • 5
  • None

69. If R1 = 10 Ωk and R2 = 100kΩ then gain of inverting amplifier is:
  • 10
  • -10
  • 100
  • None

70. Electronic circuits which implement various logic operations are called:
  • Logic gates
  • Boolean algebra
  • Amplifier gain
  • None

Written by: Asad Hussain

2 comments: