ELEX-031217

10. A long cylindrical solenoid with 200 turns/cm carries a current of 4.0 amps. The diameter of the solenoid is 0.4 cm and the length is 8.0 cm and the mass of the moon is 7.35E22 kg. What is the magnetic field inside the solenoid?

0.1005 T

13. In the series circuit shown in figure, for series resonance, the value of the coupling coefficient, k will be

0.25

16. You have an unlimited supply of 1W, 100 ohm resistors. You need to get a 100 ohm, 10W resistor. This can be done most cheaply by means of series parallel matrix of

4x4

12. Determine how long a battery will last whose rating is 100Ah; 24 Volts and will run a 300W electronic equipment and 60W light.

6.67 hrs

30. A coil is supplied with 200V and takes a current of 2A at 45˚ lagging. The Q of the coil is

1

55. How many electrons are there in the fourth orbit of a copper atom?

1

50. A certain class A power amplifier has a V =12V and I=1A. The power output is

12 W

90. An ac series circuit is composed of a resistance of 20Ω, inductive reactance of 40Ω, and a capacitive reactance of 15Ω. If a current of 1 A is flowing, what is the applied voltage?

32V

44. In a common emitter amplifier with voltage divider bias, Rin(base)=68 kilo ohms, R1=33kilo ohms, and R2= 15 kilo ohms. The total input resistance is

8.95 kΩ

57. In figure, Veb=0.6V, β=99, then Vc and Ic are

9.3V and 1.98 mA respectively

28. In two phase generators, the electrical displacement between the two phase or windings is _ electrical degrees.

90

45. At what frequency will an inductor of 5mH have the same reactance as a capacitor of 0.1 uF?

7.12 kHz

74. A wattmeter shows 57W of VA power in a circuit. The resistance is known to be 50Ω, and the true power is known to be 40W. what is the absolute value impedance?

74Ω

9. The vi characteristic of a FET is shown in figure. In which region is the device biased for a small signal amplification.

BC

84. Which of the following is not a characteristic of UJT?

Bilateral conduction

21. The transistor of following figure in Si diode with a base current of 40 and I=0, if V=6V, R=2k and beta = 90, I=20 then R=

IDK

2. Which is the following units can represent magnetic flux density?

Gauss or Tesla = (Wb/m^2)

92. What happens to photoconductive material when light strikes on it?

The conductivity of the material increases

97. The stat of SR latch when both signals are '1'

Not allowed

78. Which of the following is not a main CMOS technology?

Quad-well process

23. The result of rust in electrical (wire) connection is

Resistance

95. Which of these is not a required condition for a balanced system?

Source voltages are 120˚ out of phase with each other

81. Synchronous circuits that are synchronized to a specific __ signal.

clock

65. An emitter follower is equivalent to

common collector amplifier

72. An SCS can be turned off by any of the following except

completely interrupt anode current

87. A linear circuit is one whose parameters

do not change with voltage and current

4. A positive electric pole

has a fewer electrons than a negative pole

8. A dc electromagnet

has constant polarity

54. An IGBT is generally used in

high voltage applications

51. The input impedance of an amplifier ___ when negative current feedback is applied

increases

69. When the collector resistor in a common emitter amplifier is increased in value the voltage gain

increases

35. What is the purpose of the bypass capacitor in a common emitter amplifier?

increases the voltage gain

85. When the net reactance in a series coil capacitor circuit is zero at frequency f, the nature of its reactance of frequency 2f is

inductive

47. What is the disadvantage of impedance matching?

it gives distorted output

82. Which of the following is a way of decreasing mutual inductance?

moving the coils apart

41. When the number of free electrons is increased in doped semiconductor, it becomes a/an ___ semiconductor.

n type

66. When a differential amplifier is operated single ended

one input is grounded, and a signal is applied to the other

59. The ratio of W/VA in an ac circuit means

power factor

71. What is usually employed at the output stage of an amplifier?

push-pull amplifiers

60. If the angle of incident of a light ray is greater than the critical angle, the light be

reflection

1. If a certain circuit has a current that is lagging the voltage by 45°, then it displays

resistance and inductive reactance

39. The capacitors are considered ___ in the dc equivalent circuit of a transistor amplifier.

short

6. When a charge builds up without flow of current, the charge is said to be:

static

18. In a series connected string of holiday ornamental bulbs, if one gets shorted out, which of these is most likely?

the current in the string will go up

89. Photoconductive effect means

the increased conductivity of an illuminated semiconductor junction

73. The operating point is generally located at ___ of dc load line in class A operation

the middle

79. What determines the magnitude of electric current?

the rate at which electrons pass a given point

48. The damping factor of an active filter determines

the response characteristic

37. VL = VC in a series RLC circuit when

the value of the impedance is minimum

33. In order to have more voltage gain from a transistor amplifier the transistor used should have

thin base

49. Delta to wye or wye to delta transformation technique is applied to a ___ network.

three-terminal

40. A small signal amplifier

uses only a small portion of its load line

32. A device that can characterize active devices such as transistors and amplifiers using S parameters, as long as they are operating in their linear mode of operation.

vector network analyzer

36. Emitter follower is a ____ circuit

voltage feedback

42. An OTA is basically

voltage-to-controlled amplifier

14. There are three resistors in parallel, with values of 22 ohms, 27 ohms and 33 ohms. A 12V battery is connected across this combination. What is the current drawn by the 33ohm resistor

0.37A

52. The output of a certain two supply class B push pull amplifier has a Vcc of 20V. If the load resistance is 50 ohms, the value of Ic(sat)is

0.4 A

67. The collector voltage of a Class B push pull amplifier with Vcc=40 Volts swings down to a minimum of 4 volts. The total power dissipation in both the transistors is 36 watts. Compute the total dc power input.

122.85W

61. How many coulombs are delivered by a storage battery in 24 hours if it is supplying current at the rate of 3A

2.592 x 10^5 C

24. Two inductors, each of 100 uH, are in series. The coefficient of coupling is 0.40. The net inductance, if the coil fields reinforce each other, is:

280 uH

3. A silicone diode has a maximum allowable junction temperature of 150°C. Find the maximum allowable power dissipation at 25°C ambient temperature if the diodes thermal resistance is 0.4°C/mW.

313 m/W

26. The resistor of 51 ohm an inductor of 22 uH and a capacitance of 150 pF are in parallel. The frequency is 1 MHz. What is the complex impedance, R +jX?

46.2 + j14.9

7. When a factor of a junction transistor is 0.98, the factor would be equivalent to __ value of transistor's beta.

49

76. What does HDL stands for

Hardware Description Language

77. For a P channel enhancement type MOSFET, determine the drain current if K = 0.278 x 10(neg)3 A/V2, VGS= (neg)4v, VP=(neg)2V, voltage equivalent at 27˚ C = 26mV

ID = 1.112mA

64. To measure power supply voltage being used by a circuit, a voltmeter

Is placed in parallel with the circuit that works from the supply.

96. What is the reason why a common collector is used for impedance matching?

Its input impedance is very high

68. A device that displays a representation of the signal level in audio equipment

VU meter

34. Which of the following will not cause a major error in an ohmmeter reading?

a small change in the resistance to be measured

17. if a transistor is operated in such a way that output current flows for 160 of the input signal, then it is ___ operation

class C

53. What is the purpose of capacitors in a transistor amplifier?

couple or bypass a.c component

100. The charging of a capacitor through a resistance obeys

exponential law

5. The power factor of a certain circuit in which the voltage lags behind the current is 80%. To increase the power to 100%, it is necessary to add _____ to the circuit.

inductance

15. Electron flow assumes charges flow from

negative to positive

43. As applied to a series RLC circuit, bandwidth means

the frequency range for maximum power transfer

11.In the circuit of the figure the function resistor R and diode D are

to limit the current and protect LED against reverse breakdown voltage

83. The state of JK latch when all signals are '1'

toggle

58. A ___ is like two parallel SCRs having a common gate and connected opposite directions.

triac

99. The input resistance of a common base amplifier is

very low

91. In an emitter follower, we employ ... negative current feedback

100%

93. The gain of an amplifier without feedback is 50 whereas with negative voltage feedback, it falls to 25. If due to ageing, the amplifier gain falls to 40, find the percentage reduction in stage gain with negative feedback.

11.2 %

38. The output and the input voltages of an emitter follower have a phase difference of

0 degree

22. A degree of phase represents:

1/360 cycle.

25. What is the halfpower bandwidth of a parallel resonant circuit which has a resonant frequency of 3.6 MHz and Q of 218?

16.5 kHz

94. What is the maximum permissible number ... in the third orbit?

18

80. What is the minimum fan out of TTL?

2

86. An advantage of rheostat over a potentiometer is that

A rheostat can handle more current

70. An XOR gate produces an output only when its two inputs are

Different

31. To amplify dc signals, multistage amplifier uses what coupling?

Direct

20. The maximum voltage output from a voltage divider:

Is equal to the supply voltage.

88. Which of the following does not have a rail to rail output?

PPL

98. Which of the following is NOT one of the three distinct regions in the characteristics curve of a diode?

Saturation region

62. In an RLC series circuit, the circuit frequency is above the resonant frequency, then

XC > XL

19. Series resonance occurs when

XL = XC (At resonance, Z=R)

27. What are the two possible breakdown mechanisms in pn junction diodes?

Zener and avalanche effects

63. What is the principal characteristic of a Zener diode?

a constant voltage under conditions of varying current

29. Varactor diodes are commonly used

as a voltage-controlled capacitance

46. The lowest frequency passed by a low pass filter is

dependent on critical frequency

56. In a phototransistor, base current is

directly proportional to the light

75. The output signal of a CE amplifier is always

out of phase with the input signal (180˚)