DEPARTMENT OF ELECTRONICS AND COMMUNICATION

COURSE: BASIC ELECTRONICS (MCQ)

COURSE CODE: EC1001-1

UNIT-1
1. The voltage at which forward current through the diode starts increasing rapidly is called as
a) Cut in voltage b) Breakdown voltage c) Saturation voltage d) Cut off voltage
2. Smaller the ripple factor, the output will have higher components of
a) DC b) AC c) spike d) pulse
3. The efficiency of full wave rectifier is about
a) 81.2 b) 0.46 c) 1.21 d) 40.6
4. In a bipolar junction transistor the collector current is controlled by
a) Base current b) Collector voltage c) Collector resistance d) None
5. If a 2 mV input signal produces a 2V output signal, what is the voltage gain?
a) 1000 b) 0.004 c) 100 d) 0.001
6. Total emitter current in BJT is
a) IB + IC b) IC + ICBO c) IC+ IE d) IB – IC
7. Which is not a MOSFET terminal?

a) Base b) Drain c) Source d) Gate

8. When the p-n junction diode is forward biased, it offers

a) low resistance b) high resistance c) low voltage d) high voltage
9. Zener diode is mainly used as
a) Voltage regulator b) Comparator c) Oscillator d) Amplifier
10. The efficiency of half wave rectifier is about
a) 81.2% b) 46 % c) 1.21% d) 40.6 %
11. What is the collector current for a C-E configuration with a beta of 100 and a base current of
30 μA?
a) 3 mA b) 3μA c) 30 μA d) 30 mA
12. In a CE amplifier circuit, the output signal generates a phase shift of
a) 1800 b) 900 c) 00 d) 2700
13. For a BJT, the following statement is true
a) IE = IC b) IB = IC c) IB = IE d) IB = αIE
14. Which transistor element is used in CMOS logic?

a) MOSFET b) JFET c) BJT d) Diode

15. When the p-n junction diode is reverse biased, it offers

a) high resistance b) low resistance c) low voltage d) high voltage
16. Higher the ripple factor, the output will have higher components of
a) AC b) DC c) spike d) pulse
17. The r.m.s value of load current in a full wave rectifier is
a) 0.707 Im b) 0.5π c) 0.5 Im d) 0.3183 Im
18. The signal voltage gain of an amplifier, AV, is defined as __________.
𝑉𝑜𝑢𝑡 𝑉𝑖𝑛 𝑉𝐵𝐸
a) 𝐴𝑉 = b) AV = IC * RC c) 𝐴𝑉 = d) 𝐴𝑉 =
𝑉𝑖𝑛 𝑉𝑜𝑢𝑡 𝑉𝐶𝐶

19. A transistor has a beta of 200 and a base current of 40 μA in CE configuration. Then the
collector current is
a) 8 mA b) 8μA c) 80 μA d) 80 mA
20. The amount of ripples present at the output of half wave rectifier is
a) 1.21 b) 0.81 c) 0.46 d) 0.50
21. Higher the ripple factor, the output will have smaller components of
a) DC b) AC c) spike d) pulse
22. When forward biased, a p-n junction diode
a) Conducts current b) Blocks current c) has high resistance d) low voltage
23. A transistor has a beta of 200 and a base current of 40 μA in CE configuration. Then the
emitter current is
a) 8.04 mA b) 80μA c) 80.04 μA d) 80 mA
24. BJT is made to work as an amplifier when it is operated in ...... region

a) Active b) Cut off c) Saturation d) Inverted mode

25. A transistor has IB = 0.08 mA and IE = 9.60 mA. The value of β is

a) 119 b) 129 c) 960 d) 100

26. The enhancement type MOSFET works only with _______.

a) large positive gate voltage b) large negative gate voltage

c) large positive source voltage d) large negative drain voltage

27. The amount of ripples present at the output of a full wave rectifier is
a) 48% b) 81% c) 42% d) 52%
28. The r.m.s value of load current in a half wave rectifier is
a) 0.5 Im b) 0.5π c) 0.707 Im d) 0.3183 Im
29. Zener diode regulates output voltage only when it is connected in
a) Reverse bias b) Forward bias c) Short d) Open
30. A transistor has IB = 0.06 mA and IE = 9.00 mA. The value of β is

a) 149 b) 129 c) 960 d) 100

31. In CE configuration of BJT, output characteristics is plotted by taking

a) VCE verses IC for constant IB b) VCE verses IC for constant IE

c) VCE verses IC for constant VCB d) VCE verse IE for constant IC

32. A highly stable biasing network used in CE-RC coupled amplifier is

a) Voltage divider biasing circuit b) Collector feedback bias circuit

c) Base bias circuit d) Emitter bias circuit

33. The MOSFET stands for

a) Metal oxide semiconductor FET b) Metal oxide surface FET

c) Metal oxidized selenium FET d) Metal of surface FET

34. A silicon diode is connected in series to a dc supply of 2 volts and resistance of 13 Ω, the
current in the circuit is
a) 0.10A b) 0.55 A c) 0.45 A d) 1.5A
35. The DC load current of a half wave rectifier is
a) Im/π b) 2Im/π c) 2Idc/π d) 1.414/π
36. A sinusoidal voltage of peak value 40V is applied to a half wave rectifier with RL = 800 Ω and
Rf = 8 Ω. The peak value of the current is
a) 49.5 mA b) 4.95 mA c) 0.495 mA d) 4.95 A
37. A transistor has IB = 0.06 mA and IE = 9.00 mA. The value of α is

a) 0.99 b) 9.9 c) 990 d) 100

38. When the transistor operates as an amplifier, the operating point is located

a) In the center of active region b) In the cut-off region

c) In the Saturation region d) In the Ohmic region

39. When BJT operates as a switch, it is operated alternately in _____________

a) Cut-off and Saturation region b) Active and cut-off region

c) Saturation and active region d) Active and saturation region

40. MOSFET has greatest application in digital circuit due to

a) Low power consumption b) Less noise

c) Small amount of space it takes on a chip d) None

41. A silicon diode is connected in series to a dc supply of 5 Volts and resistance of 1.5 kΩ, the
current in the circuit is
a) 2.86 mA b) 3.86 mA c) 0.38 mA d) 1.5mA
42. Average DC load voltage of a full wave Bridge rectifier is
a) 2Vm/π b) 2Im/π c) Im/0.707 d) Im/0.5
43. What is the state of an ideal diode in the region of non-conduction?
a) Open circuit b) Short circuit c) Unpredictable d) Undefined
44. A transistor has IB = 0.08 mA and IE = 9.60 mA. The value of α is

a) 0.99 b) 9.9 c) 990 d) 100

45. The collector to base current gain β in terms of α is defined as

𝛼
a)
1−𝛼

𝛼
b)
1+𝛼

𝛽
c)
1+𝛼

𝛽
d)
1+𝛽

46. The collector to emitter current gain α in terms of β is defined as

𝛽
a)
1+𝛽

𝛼
b)
1−𝛼

𝛽
c)
1+𝛼

𝛼
d)
1+𝛼

47. A germanium diode is connected in series to a dc supply of 4volts and resistance of 2 kΩ, the
current in the circuit is
a) 1.85 mA b) 1.45mA c) 0.185 mA d) 18.5 mA
48. What is the resistance of an ideal diode in the region of conduction?
a) 0 Ω b) 5 kΩ c) Unpredictable d) Infinity
49. A zener diode of 10V is connected to a supply of 20V through a series resistance of 200

ohms. With no load, current through the zener is

a) 50 mA b) 500 mA c) 5 A d) 400 mA
50. The leakage current in a transistor is due to:
a) Minority charge carriers b) Majority charge carriers
c) Zener effect d) Breakdown
51. A bipolar junction transistor is a
a) Current controlled device b) Voltage controlled device
c) Resistance controlled device d) Junction controlled device

52. The range of collector to emitter current gain α is

a) 0.96 to 0.99 b) 20 to 200 c) 0.76 to 0.96 d) 0.50 to 1

53. A germanium diode is connected in series to a dc supply of 7.5 volts and resistance of 1.3
kΩ, the current in the circuit is
a) 5.53 mA b) 5.53 A c) 5.35 mA d) 1.53 mA
54. A Zener diode is a heavily doped semiconductor device that is designed to operate in
a) Reverse direction b) Forward direction c) Both forward and reverse d) None
55. The range of collector to base current gain β is

a) 20 to 200 b) 20 to 100 c) 50 to 100 d) 10 to 50

56. The value of β for a silicon transistor given the collector current as 1 mA and base current as
25 µA is

a) 40 b) 4 c) 400 d) 4000

57. The value of α for a silicon transistor, given the collector current as 1 mA and base current
as 25 µA is

a) 0.9756 b) 0.9276 c) 0.9376 d) 0.9176

58. A silicon and a germanium diodes are connected in series to a dc supply of 8 volts and
resistance of 2.5 kΩ, the current in the circuit is
a) 2.8 mA b) 28 mA c) 0.28 mA d) 2.8 A
59. In the breakdown region, zener diode behaves like a source of
a) Constant voltage b) Constant current c) Constant resistance d) Constant power
60. A resistance is connected in series with zener diode in a voltage regulator to
a) Protect the zener b) Properly reverse bias the zener
c) Properly forward bias the zener d) switch off the zener
61. The value of β for a silicon transistor given the collector current as 1 mA and base current as
10 µA is

a) 100 b) 10 c) 0.1 d) 1000

62. The value of α for a silicon transistor, given the collector current as 1 mA and base current
as 10 µA is

a) 0.9900 b) 0.9276 c) 0.9376 d) 0.9176

63. In CE-RC coupled amplifier, an emitter bypass capacitor is connected in parallel with emitter
resistance RE to

a) To provide a low reactance path to the amplified ac signal

b) Increase the noise in the circuit

c) To support the resistance RE

d) To block the dc voltage

64. In which one of the following rectifiers the efficiency is low?

a) Half-wave b) Full-wave c) Bridge d) None of these

65. Ripple factor for a full wave bridge rectifier with capacitor filter is

𝟏 1 1 1
a) b) c) d)
𝟒√𝟑𝒇𝑪𝑹𝑳 2√3𝑓𝐶𝑅𝐿 2𝑓𝐶𝑅𝐿 4𝑓𝐶𝑅𝐿

66. If an emitter current is changed by 4mA, the collector current changes by 3.5mA. The value
of β will be:

a) 7 b) 0.875 c) 0.5 d) 3.5

67. Which of the following statement is correct?

a) Rectification efficiency of a half wave rectifier is equal to that of the Full wave rectifier

b) All of the given options

c) Rectification efficiency of a half wave rectifier is lower than that of the Full wave rectifier
d) Rectification efficiency of a half wave rectifier is higher than that of the Full wave rectifier

68. A MOSFET is a

a) Current controlled device

b) Voltage controlled device
c) Resistance controlled device
d) Junction controlled device
69. In a Full wave bridge rectifier, the number of diodes conducting at a time during one half cycle
of the input signal is

a) 2 b) 4 c) 3 d) 1

70. The doping level in a zener diode is …………… that of a PN diode.

a) the same as

b) less than

c) more than

d) none of the above

71. A MOSFET has…………………………….. terminals.

a) two b) five c) four d) three

72. The number of depletion layers in a transistor is …………

a) four b) three c) one d) two

73. The base of a transistor is ………….. doped

a) heavily
b) moderately
c) lightly
d) none of the above

74. The emitter of a transistor is ………………… doped

a) lightly
 b) heavily
c) moderately
d) none of the above

75. The value of α of a transistor is ……….

a) more than 1
b) less than 1
c) 1
d) none of the above

76. The value of β for a transistor is generally ………………..

a) 1
b) less than 1
c) between 20 and 500
d) above 500

77. If the value of α is 0.9, then value of β is ………..

a) 9
b) 0.9
c) 900
d) 90

78. In a transistor, signal is transferred from a …………… circuit

a) high resistance to low resistance

b) low resistance to high resistance
c) high resistance to high resistance
d) low resistance to low resistance

79. With the E-MOSFET, when gate input voltage is zero, drain current is …..

a) at saturation
b) zero
c) IDSS
 d) widening the channel

80. MOSFET has a thin layer of silicon dioxide, which act as:

a) Resistance
b) Inductor
c) Semiconductor
d) Capacitor

UNIT-II
1. Which of the following electrical characteristics is not exhibited by an ideal op-amp?
a) Infinite output resistance b) Infinite bandwidth

c) Infinite voltage gain d) Infinite slew rate

2. An integrator circuit using an Op Amp has ……………….in its feedback path

a) Capacitor b) Resistor c) inductor d) Diode

3. The representation 555 for IC 555 timer is mainly because

a) It has a series of three 5𝑘 𝛺 resistors in the internal circuitry

b) It has voltage levels of 5V in the internal circuitry

c) It has five Op Amp comparators internally

d) None of these

4. IC 555 timer working as a free running oscillator is a

a) DC to AC converter b) AC to DC converter

d) DC to DC converter d) DC to DC inverter

5. In Colpitts’ oscillator, the components used in the feedback network are

a) 2C and 1L b) 2L and 1C c) 2R and 2C d) 2L and 2C

6. With a resistance value of R=1kΩ in a feedback network of RC oscillator, frequency of
oscillations generated is 5 kHz. The value of the capacitor C is

a) 0.0129 𝜇𝐹 b) 0.129 𝜇𝐹 c) 0.0219 𝜇𝐹 d) 129 𝜇𝐹

𝐴
7. Gain with negative feedback is given by 𝐴𝑓 = 1+𝐴𝛽. The feedback factor is

a) 𝛽 b) A c) Af d) None

8. An amplifier has an open loop voltage gain of 1000. If 10% negative voltage series feedback is
used, then the closed loop gain is

a) 9.9 b) 99.9 c) 0.9 d) 990

9. Find the output voltage of an ideal op-amp if V1 and V2 are the two input voltages
a) 𝑉0 = 𝐴( 𝑉1 − 𝑉2 ) b) 𝑉0 = 𝑉1 − 𝑉2 c) 𝑉0 = 𝐴( 𝑉1 + 𝑉2 ) d) 𝑉0 = 𝑉1 × 𝑉2

10. A differentiator circuit using an Op Amp has ……………….in its feedback path

a) Resistor b) Capacitor c) Inductor d) Diode

11. The voltage levels fixed at one of the terminals of two comparators in the internal circuitry of

IC 555 timer are

1 2
a) 𝑉 & 𝑉
3 𝑐𝑐 3 𝑐𝑐

2
b) 𝑉𝑐𝑐 & 5 𝑉𝑐𝑐

1 2
c) 𝑉 & 𝑉
5 𝑐𝑐 5 𝑐𝑐

2
d) 0𝑉 & 𝑉𝑐𝑐
5

12. A sine wave of 0.5 V peak voltage is applied as an input to an inverting amplifier with R1 = 10
kΩ and Rf = 50 kΩ The output voltage Vo is

a) -2.5 V peak b) 5.2 V peak c) -10 V peak d) -2.5 V peak-peak

13. In Hartley oscillator, the components used in the feedback network are
a) 2L and 1C b) 2L and 2C c) 2R and 2C d) 1L and 2C

14. For an amplifier with negative feedback, the closed loop gain is given by

𝐴
a) 𝐴𝑓 = 1+𝐴𝛽

𝐴
b) 𝐴𝑓 = 1−𝐴𝛽

𝐴
c) 𝐴𝑓 = 1−𝛽

𝐴
d) 𝐴𝑓 = 1−𝑉𝛽

15. In a practical oscillator circuit, to start oscillations, the loop gain Aβ must be

a) Greater than 1 b) Equal to 1 c) Less than 1 d) Not equal to 1

16. An amplifier has an open loop voltage gain of 2000. If 40% negative voltage series feedback
is used, then the closed loop gain is

a) 2.49 b) 24.9 c) 0.249 d) 249

17. The output voltage obtained for an ideal op-amp is by

a) Amplifying the difference between the two input voltages
b) Amplifying individual input voltages
c) Amplifying products of two input voltage
d) None of the mentioned

18. The output voltage 𝑉0 of an Op Amp integrator is given by

1 𝑡 1 𝑡
a) 𝑉0 = − 𝑅 ∫0 𝑉𝑖𝑛 𝑑𝑡 b) 𝑉0 = − 𝐶 ∫0 𝑉𝑖𝑛 𝑑𝑡
𝐶
1 𝑓 𝑓

1 𝑡 1 𝑡
c) 𝑉0 = − 𝑅 ∫−∞ 𝑉𝑖𝑛 𝑑𝑡 d) 𝑉0 = − 𝑅 ∫0 𝑉𝑖𝑛 𝑑𝑡
𝐶
1 𝑓 𝐶
𝑓 1

19. The outputs of two comparators are connected to a ………………… in the internal circuitry
of IC 555 timer

a) S-R Flip Flop b) D-type Flip Flop c) J-K Flip Flop d) T-Type Flip Flop
20. A sine wave of 0.5 V peak voltage is applied as an input to a non- inverting amplifier with R1
= 10 kΩ and Rf = 50 kΩ The output voltage Vo is

a) 3 V peak b) 2.5 V peak c) -3 V peak d) 3 V peak-peak

21. In an amplifier, positive feedback leads to

a) Oscillations b) Amplification c) Breakdown d) None of these

22. For an amplifier with positive feedback, the closed loop gain is given by

𝐴
a) 𝐴𝑓 = 1−𝐴𝛽

𝐴
b) 𝐴𝑓 = 1+𝐴𝛽

𝐴
c) 𝐴𝑓 = 1−𝛽

𝐴
d) 𝐴𝑓 = 1−𝑉𝛽

23. What is an oscillator?

a) A rectifier b) A generator c) An amplifier with positive feedback d) An amplifier with

positive feedback

24. An amplifier has an open loop voltage gain of 100,000. If the negative voltage series feedback
factor is 0.01, then the closed loop gain is

a) 99.9 b) 9.9 c) 0.9 d) 990

25. Which is not the ideal characteristic of an op-amp?

a) Input Resistance is zero
b) Output impedance is zero
c) Bandwidth is infinity
d) Open loop voltage gain is infinity
26. The output voltage 𝑉0 of an Op Amp differentiator is given by

𝑑𝑉𝑖𝑛 1 𝑡
a) 𝑉0 = −𝑅𝑓 𝐶 b) 𝑉0 = − 𝐶 ∫0 𝑉𝑖𝑛 𝑑𝑡
𝑑𝑡 𝑓
 1 𝑑𝑉𝑖𝑛 1 𝑡
c) 𝑉0 = − 𝑅 d) 𝑉0 = − 𝑅 ∫0 𝑉𝑖𝑛 𝑑𝑡
𝑓𝐶 𝑑𝑡 𝑓

27. The charging time or ON time of the capacitor in Astable mode of operation using IC 555 timer
is

a) 𝑇𝑂𝑁 = 0.693(𝑅1 + 𝑅2 )𝐶 b) 𝑇𝑂𝑁 = 0.693(𝑅2 )𝐶

c) 𝑇𝑂𝑁 = 0.693(𝑅1 )𝐶 d)𝑇𝑂𝑁 = 0.693(𝐹)𝐶

28. A sine wave of 0.5 V peak voltage is applied as an input to a non- inverting amplifier with R1
= 12 kΩ and Rf = 24 kΩ The output voltage Vo is

a) 1.5 V peak b) -2.5 V peak c) 10 V peak d) -5 V peak

29. In an amplifier with positive feedback, open loop gain A is 20 with feedback factor 𝛽 as 0.04.
Then the gain of the amplifier with feedback is

a) 100 b) 50 c) 200 d) Infinity

30. The feedback factor of Colpitt’s oscillator is given by

𝐶
a) 𝛽 = 𝐶2
1

𝐶
b) 𝛽 = 𝐶1
2

𝐴
c) 𝛽 = 𝐴
𝑓

𝐴𝑓
d) 𝛽 = 𝐴

31. Which of the following is not the advantages of negative feedback amplifier?

a) Unstable gain b) Higher input impedance c) Reduction in noise d) Lower output impedance

32. An amplifier has an open loop voltage gain of 10,000. If the negative voltage series feedback
factor is 0.01, then the closed loop gain is

a) 99 b) 9.9 c) 0.9 d) 990

33. Which factor determines the output voltage of an op-amp?
a) Both positive and negative saturation voltage b) Negative saturation
c) Positive saturation d) Supply voltage

34. The output voltage swing of a comparator for an applied input voltage depends on

a) Dual power supply voltages b) Regulated power supply voltages

c) AC signals applied at the terminals of the Op Amp d) DC signals applied at the terminals
of the Op Amp

35. The two Op Amps used in the internal circuit of IC 555 timer function as

a) Comparators b) voltage followers c) Differentiators d) Amplifiers

36. A sine wave of 0.5 V peak voltage is applied as an input to an inverting amplifier with R1 = 12
kΩ and Rf = 24 kΩ The output voltage Vo is

a) -1.0 V peak b) -2.5 V peak c) -1 V peak-peak d) -5 V peak

37. In an amplifier with negative feedback, open loop gain A is 20 with feedback factor 𝛽 as 0.04.
Then the gain of the amplifier with feedback is

a) 11.11 b) 100 c) 200 d) Infinity

38. The feedback factor of Hartley oscillator is given by

𝐿1
a) 𝛽 = 𝐿2

𝐿
b) 𝛽 = 𝐿2
1

𝐴
c) 𝛽 =
𝐴𝑓

𝐴𝑓
d) 𝛽 = 𝐴

39. Which among the following parameters acts as an initiator for the operation of an oscillator
in the absence of input signal?

a) Noise voltage b) Noise power c) Noise current d) Noise temperature

40. In which type of oscillator circuit capacitor split representation can be seen in tank circuit?

a) Colpitts b) RC phase shift c) Hartley d) Weinbridge

41. A non-inverting closed loop op amp circuit generally has a gain factor
a) Greater than one b) Less than one c) Zero d) Equal to one

42. An inverting amplifier using Op Amp with 𝑅1 𝑎𝑛𝑑 𝑅𝑓 as the resistors provide an output
voltage equal to one of them as

𝑅
a) 𝑉0 = − (𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
b) 𝑉0 = − (1 + 𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
c)𝑉0 = (1 + 𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
d) 𝑉0 = (𝑅𝑓 ) 𝑉𝑖𝑛
1

43. The duty cycle ‘D’ of IC 555 timer in astable mode in terms of its time period is defined by

𝑇𝑂𝑁 𝑇 𝑇
a) 𝑇 b) 𝑇 𝑂𝑁 c) d) None
𝑂𝑁 +𝑇𝑂𝐹𝐹 𝑂𝐹𝐹 𝑇𝑂𝐹𝐹

44. A sine wave of 0.5 V peak voltage is applied as an input to a non- inverting amplifier with R1
= 6 kΩ and Rf = 24 kΩ The output voltage Vo is

a) 2.5 V peak b) -2.5 V peak c) 10 V peak d) 2.5 V peak-peak

45. In an RC phase shift oscillator, the resistances in the feedback network are 4.7 kΩ and capacitor
values are C = 0.47µF. The frequency of oscillations is

a) 29.413 Hz b) 294.13 Hz c) 2941.3 Hz d) None of these

46. Negative feedback amplifier

a) Reduces gain b) Increases gain c) Increases noise d) Reduces phase shift

47. The tank circuit of a Colpitt’s oscillator has L= 5 mH with C1 = 22.22 nF and C2 = 2.22 nF.
The feedback factor β is
a) 0.1 b) 0.001 c) 0.01 d) 1

48. In which type of oscillator circuit inductor split representation can be seen in tank circuit?

a) Hartley b) RC phase shift c) Colpitts d) Wein bridge

49. An ideal OP-AMP has following characteristics

a) Ri = infinity, A = infinity, Ro = infinity

b) Ri = 0, A=infinity Ro = zero
c) Ri = infinity, A = 0, Ro = infinity

d) Ri = 0, A = infinity, Ro = infinity

50. A non-inverting amplifier using Op Amp with R1 and Rf as the resistors provide an output
voltage equal to one of them as

𝑅
a) 𝑉0 = (1 + 𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
b) 𝑉0 = − (𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
c) 𝑉0 = − (1 + 𝑅𝑓 ) 𝑉𝑖𝑛
1

𝑅
d) 𝑉0 = (𝑅𝑓 ) 𝑉𝑖𝑛
1

51. The duty cycle ‘D’ of IC 555 timer in astable mode in terms of resistors used in the external
circuit is defined by

𝑅1 +𝑅2
a) 𝑅1 +2𝑅2

𝑅1 +2𝑅2
b)
𝑅1 +𝑅2

𝑅1 −𝑅2
c) 𝑅1 −2𝑅2

𝑅1 +𝑅2
d) 𝑅1 −2𝑅2

52. A non-inverting Op-Amp has a gain of 61 with R1 = 1 kΩ. The resistor in the feedback path
must have a value of
a) 60 kΩ b) 59 kΩ c) 61 kΩ d) 62 kΩ

53. An RC network in an RC phase shift oscillator has C = 0.1 µF. The frequency of oscillations
is 1 kHz. The value of R used in the feedback network is

a) 650 Ω b) 500 Ω c) 600 Ω d) 1 kΩ

54. RC phase shift oscillator is a

a) Low frequency oscillator b) High frequency oscillator

c) Stable frequency oscillator d) Relaxation oscillator
55. In a Hartley oscillator, if L1 = 5 mH, L2 = 10 mH and C = 0.01µF, the value of the feedback
factor β is

a) 0.5 b) 0.05 c) 50 d) 500

56. The frequency of oscillations generated by RC phase shift oscillator is

1 1 1 1
a) 2𝜋√6𝑅𝐶 b) 2𝜋𝑅𝐶 c) 2𝜋√6𝑅𝐶 d) 2𝜋6𝑅𝐶

57. For an Op-Amp having differential gain Ad and Common mode gain Ac, CMRR is
a) Ad/Ac b) Ad + Ac c) 1+ (Ad/Ac) d) Ac/Ad

58 A voltage follower using Op Amp is also known as

a) Buffer amplifier b) Non inverting amplifier c) Inverting amplifier d) Switch

59. The pin number 7 in IC 555 timer is assigned as

a) Discharge pin b) Threshold pin c) output pin d) None of these

60. A non-inverting Op-Amp has a gain of 61 with R1 = 2 kΩ. The resistor in the feedback path
must have a value of

a) 120 kΩ b) 121 kΩ c) 61 kΩ d) 62 kΩ

61. An RC network in an RC phase shift oscillator has C = 0.2 µF. The frequency of oscillations
is 1 kHz. The value of R used in the feedback network is

a) 325 Ω b) 500 Ω c) 600 Ω d) 1 kΩ

62. Hartley oscillator is a

a) High frequency oscillator b) Stable frequency oscillator

c) Low frequency oscillator d) Relaxation oscillator
63. In a Hartley oscillator, if L1 = 7 mH, L2 = 10 mH and C = 0.01µF, the value of the feedback
factor β is

a) 0.7 b) 0.07 c) 70 d) 700

64. The frequency of oscillations generated by Colpitts oscillator is

1 1 1 1
a) 2𝜋 b) 2𝜋 c) 2𝜋√𝐿𝐶 d) 2𝜋𝐿𝐶
√𝐿𝐶𝑒𝑞 √𝐿𝑒𝑞 𝐶

65. A simple application of an Op-Amp that can be used to generate a gain of unity is
a) Voltage follower b) Differentiator c) Integrator d) Comparartor

66. Op Amp Comparator is a circuit whose output voltage switches between

a) +𝑉𝑠𝑎𝑡 , −𝑉𝑠𝑎𝑡 b) +𝑉𝑖𝑛 , −𝑉𝑖𝑛 c) +𝑉𝑜 , −𝑉𝑜 d) None

67. The discharge pin in IC 555 timer is connected to ----------------- of the transistor.

a) Collector terminal b) Emitter terminal c) Base terminal d) None of these

68. An inverting Op-Amp has a gain of - 61 with R1 = 1 kΩ. The resistor in the feedback path
must have a value of

a) 61 kΩ b) 59 kΩ c) 60 kΩ d) 62 kΩ

69. The components in the feedback network of LC oscillators are

a) L & C components b) R & C components c) Only L Component d) None of these

70. What is an angle of phase shift for each designed RC network in the Phase Shift Oscillator
circuit?

a) 600 b) 450 c) 300 d) 900

71. In a Hartley oscillator, if L1 = 2 mH, L2 = 8 mH and C = 0.01µF, the value of the feedback
factor β is
a) 0.25 b) 0.025 c) 250 d) 25

72. The frequency of oscillations generated by Hartley oscillator is

1 1 1 1
a) 2𝜋 b) c) 2𝜋√𝐿𝐶 d) 2𝜋𝐿𝐶
√𝐿𝑒𝑞 𝐶 2𝜋√𝐿𝐶𝑒𝑞

73. For an ideal op-amp, which of the following is false?

a) The current from output terminal is zero

b) The current into the input terminals is zero

c) The differential voltage between the input terminals is zero
d) The output resistance is zero

74. With reference to the output voltage of an inverting Op Amp summer 𝑉0 =

𝑅 𝑅 𝑅
− (𝑅𝑓 𝑉1 + 𝑅𝑓 𝑉2 + 𝑅𝑓 𝑉3 ), if 𝑅𝑓 = 𝑅1 = 𝑅2 = 𝑅3 = 𝑅, then
1 2 3

a) 𝑉0 = −(𝑉1 + 𝑉2 + 𝑉3 )

b) 𝑉0 = −𝑉1 + 𝑉2 + 𝑉3

c) 𝑉0 = 𝑉1 + 𝑉2 + 𝑉3

d) None of these

75. The duty cycle D in astable mode using IC 555 is obtained using

a) External resistors b) Internally connected resistors

c) Comparators d) RS Flip flop

76. An inverting Op-Amp has a gain of - 61 with R1 = 1 kΩ. The resistor in the feedback path
must have a value of

a) 162kΩ b) 82 kΩ c) 182 kΩ d) 62 kΩ

77. In an RC-Phase shift oscillator, the components used in the feedback network are

a) 3R and 3C b) 1R and 1C c) 4R and 4C d) 2R and 2L

𝐴
78. Gain with negative feedback is given by 𝐴𝑓 = 1−𝐴𝛽. The feedback factor is
a) 𝛽 b) A c) Af d) None

79. In a Colpitts oscillator, if C1 = 100 pF, C2 = 60 pF and L = 0.422 H, the value of the feedback
factor β is

a) 0.6 b) 0.06 c) 60 d) 600

80. The criterion that determines mathematical condition to generate sustained oscillations is
a) Barkhausen b) Shockley c) Pinch off d) Threshold

UNIT-III

1. The unit used for measuring Message or information is

(a) bits per second (b) Hertz (c) Ohms (d) meter per second
2. The initial mobile communication systems for public safety in United states used the following
modulation technique,
a) Amplitude modulation
b) Frequency modulation
c) Phase modulation
d) Time based modulation
3. Actuators are used to
a) Make a mechanical movement
b) Sense an object
c) Activate a chemical
d) All of the above
4. The function of a sensor is to ________
a) Detect events within specified environment
b) Separate physical parameters
c) Only Track the data
d) None
5. Fibre optic cable is a ------------ type of channel.

(a) Wired channel (b) Free space channel (c) Radio channel (d) Wireless channel
6. The mechanism of using the same frequency band within a geographical area in a Cellular or
mobile communication system is referred to as,

a) Frequency reuse
b) Efficiency
c) Reliability
d) Bandwidth coordination
7. A microcontroller at-least should consist of:
a) CPU, RAM, ROM, I/O ports and timers
b) RAM, ROM, I/O ports and timers
c) CPU, RAM, I/O ports and timers
d) CPU, ROM, I/O ports and timers

8. Which of the following is true about microprocessors?

a) It contains ALU, CU, and registers
b) It has an internal memory
c) It has interfacing circuits
d) It uses Harvard architecture
9. ------- converts the information into signal suitable to be transmitted over the communication
medium.
(b) Transmitter (b) Transmission line (c) Receiver (d) Channel
10. Which of the following is not an example of a Small-Scale Embedded Systems?
a) Cell Phone
b) Electronic Barbie doll
c) Simple Calculator
d) Electronic Toy Car

10. In a communication system, the noise can be generated at the

(a) transmitter, channel, receiver (b) channel, receiver

(c) transmitter, channel (d) only in the channel

11. A fixed station in a mobile radio system used for radio communication with the mobile stations
is

a) Base station b) Cellular station c) Switching center d) Public switching station

12. Which of the following is true about optocouplers?

a) Optocoupler can be used in both input and output circuitry
b) Optocoupler acts as an input device only
c) Optocoupler acts as an output device only
d) None of these
13. Which of the following is example for the input subsystem of an embedded system?
a) Optocoupler
b) LED
c) Seven Segment
d) None of these
14. Best example for natural noise is

(a) Rain (b) Traffic noise (c) Industrial noise (d) Sound pollution

15. The radio channel used for transmission of information from a base station to a mobile station
is called,

a) Forward channel
b) Reverse channel
c) Control channel
d) Mobile channel

16. Which one of the following offers external chips for memory and peripheral interface circuits?
a) Microprocessor
b) Microcontroller
c) Embedded system
d) Peripheral System
17. Best example for man-made noise is
(a) Traffic noise (b) Rain (c) Radiations from sun, stars (d) Reflections from
earth
18. The process of transferring a mobile station from one base station to another base station is
called
a) Hand-off
b) Channel efficiency
c) Frequency reuse
d) Frequency Division Duplexing

19. The speech signal frequency range is

(a) 300 Hz to 3.4 kHz (b) 20 Hz to 20 kHz (c) 30 to 34 kHz (d) 10 to 10 kHz
20. In a cellular radio system, the _________________ connects the cellular base stations and
mobile stations to the Public Switched Telephone Networks.

a) Mobile Switching Center (MSO)

b) Base station’(BS)
c) Forward Control Channel (FCC)
d) Time Division Multiple Access (TDMA)
21. ASIC stands for?

a) Application Specific Integrated Circuit

b) Avionics Subsystem Interface Contractor
c) Aviation Security Identification Card
d)Application-Specific introduction code

22. The audio frequency range is

(a) 20 Hz to 20 kHz (b) 30 to 34 kHz (c) 300 Hz to 3.4 kHz (d) 10 to 10 kHz
23. Which of the following is true about Embedded System?
a) All of them
b) An embedded system usually performs a specialized operation and does the same repeatedly
c) It must have a memory, as its software usually embeds in ROM
d) It must have connected peripherals to connect input and output devices.
24. The loss in the transmission is minimum for the following type of wire
(a) Fiber optic cable (b) Coaxial cable (c) Flat cable (d) Copper wire
25. The following frequency band is utilized in cellular or mobile communication system,
 a) Radio frequency
b) Audio frequency
c) Audible frequency
d) Unlicensed frequency
26. On which component modulation is performed?

a) Transmitter
b) Signal
c) Jammer
d) None of the above

27. What kind of modulation is used in television for sound signal?

a) Amplitude modulation
b) Frequency modulation
c) Phase modulation
d) Both a and b

28. What is modulated signal?

a) It is the product of modulating signal and carrier signal

b) It is the product of modulating signal and information signal
c) It is an input signal
d) None of the above

29. A microprocessor with 8-bit can process ______ bits of data at a time.

a) 4
b) 8
c) 12
d) 16

30. What is the primary difference between a microcontroller and a microprocessor?

a) Microcontrollers have higher clock speeds than microprocessors.

b) Microcontrollers have built-in memory and peripherals.
c) Microprocessors have built-in ADCs and DACs.
d) Microprocessors are smaller in size.