3

1. Divergence of the three dimensional radial vector field is

A. 3

B.

C.

D.

2. If ),,( zyx is a scalar function, then

is

A. 1

B. 0

C. 3

D. -3

3. If )(sF is the Laplace transform of )(tf , then the Laplace transform of t

df0

)( is

equal to

A. )(1

sFs

s

B. )(1

sFs

C. )(ssF

D. dssF )(

4. Given a matrix

34

24, one of its eigen vectors is

A.

2

1

B.

2

3

C.

1

2

D.

3

4

4

5. If x and y satisfy the implicit function 0),( xy yxyxf , then x

y

d

dis given by

A.

xy

x

yx

y

ln

ln

B.

xx

y

yy

x

ln

ln

C. 2

2

x

y

y

x

D. xyx

yxy

ln

ln

6. The Newton Raphson method formula for finding the square root of a real number R

from the equation 02 Rx is

A. 2

1i

i

xx

B. 2

31

ii

xx

C.

iii

x

Rxx 3

2

11

D.

iii

x

Rxx

2

11

7. Determinant of a 5 × 5 orthogonal matrix can take values

A. 0

B. 1 C. 25

D. 5

8. The signal )(tx is described by otherwise 0 and ,11for 1)( x(t)ttx . The two

angular frequencies at which its Fourier transform becomes zero are

A. 5.0 , 5.1

B. 0 ,

C. , 2

D. 5.0 , 5.2

5

9. Which of the options correspond to derivative of the symmetric function shown below

A.

B.

C.

D.

10. The Laplace Transform of the function shown in the figure (sum of two delta functions)

is given by

A. sj cos2

B. sj sin2

C. Zero

D. scos2

11. The value of integral is

A.

B.

C.

D.

t -1

f(t)

1

6

12. If Laplace transform of is then Laplace transform of

is

A.

B.

C.

D.

13. If f(x) is a symmetric periodic function of x, then the Fourier series of the function f(x)

will be of the form

A.

B.

C.

D.

14. If ˆˆ ˆr xi yj zk

, then 2

( )rgrad e has the value

A. 2

2 rrre

B. 2

2 rre

C. 21

2

rre

D. 2rre

15. The complete solution of the differential equation 2

25 6 xd y dy

y edx dx

is:

A. 2

1 22

xx x e

y c e c e

B. 2 3

1 22

xx x e

y c e c e

C. 22

1 3

2

2

1

xxx e

ececy

D. 2

1 2( )2

xx e

y c c x e

7

16. The value of the contour integral

C z

z2

2

3, C is the unit circle (counterclockwise) is

A. 24πi

B. 0

C. 12πi

D. 6πi

17. The Laplace transform of t

tf3

)(

is

A. 3s

B. 33

C. 3

D. 3 s

18. The intensity pattern shown in the figure is the diffraction pattern for a N-slit array with

slit width b and slit seperation a . The values of N and b

aare

A. 2 and 3

B. 3 and 2

C. 4 and 3

D. 5 and 2

19. In the design of a single mode step index optical fiber close to upper cut off , the single

mode operation is NOT preserved if

A. radius as well as operating wavelength are halved

B. radius as well as operating wavelength are doubled

C. radius is doubled and operating wavelength is halved

D. radius is halved and operating wavelength is doubled

20. The work function of silver and sodium are 4.6 eV and 2.3 eV respectively. The ratio of

the slope of the stopping potential versus frequency plot for silver and sodium in a

photoelectric effect experiment is

A. 2

1

B. 2

C. 1

D. 2

8

21. The refractive index of glass is 1.5. The wavelength of light with frequency 1014

Hz in

glass is

A. m 2

B. m 3

C. m .54

D. m 1

22. The wave function of a quantum mechanical particle is given by

)(5

4)(

5

3)( 21 xxx

where )(1 x and )(2 x are eigenfunctions with eigenvalues -1 eV and -2 eV respectively.

The energy of the particle in the state )(x is

A. 5

11

B. 25

41

C. 25

36

D. 5

7

23. Unpolarized light of intensity I0 is incident on two ideal linear polarizers whose

transmission axes differ by 60 degrees. The intensity of the transmitted light is

A. 4

I0

B. 2

I0

C. 8

I0

D. 4

3I0

24. X rays are

A. Cathode rays and are made of electrons

B. Positive rays and made of positrons.

C. Neutral and made of photons.

D. Neutral and made of neutrons.

9

25. If λo is the de Broglie wavelength for a proton accelerated through a potential V, then the

de Broglie wavelength for an α particle accelerated through the same potential is

A. 22/o

B. o22

C. 2/o

D. 2/o

26. In C language, which of the following special symbols is allowed in a variable name?

A. * (asterisk)

B. _ (underscore)

C. | (pipeline)

D. – (hyphen)

27. In the C program given below, point out the error, if any, in the for loop

main()

int i=1;

for (;;)

printf(“%d”, i++);

if(i>10)

break;

A. The condition in the for loop is a must.

B. The two semicolons should be dropped.

C. The for loop should be replaced by a while loop.

D. No error.

28. In C language, which function is used to round off a value from 1.66 to 2.0?

A. floor(1.66)

B. roundup(1.66)

C. ceil(1.66)

D. rountdto(1.66)

10

29. What would be the output of the following C program, if the array begins at address

1200?

main()

int arr[ ] = 2,3,4,1,6;

printf(“%d%d”, arr, sizeof(arr));

A. 1201 5

B. 1200 1024

C. 1201 1024

D. 1200 10

30. If the sequence of operation – push (1), push (2), pop, push (1), push (2), pop, pop,

pop, push (2), pop are performed on a stack, the sequence of the popped out values are

A. 2 2 1 2 2

B. 2 1 1 2 2

C. 2 2 1 1 2

D. 2 1 2 2 2

31. Which of the following is a PNPN device and has two common gates ?

A. DIAC

B. SCR

C. BJT

D. TRIAC

32. A n-type semiconductor has Hall coefficient of 150 cm3/C and resistivity ρ = 0.05 Ω cm.

The electron mobility will be

A. 3000 cm2/V-s

B. 2560 cm2/V-s

C. 25.60 cm2/V-s

D. 2000 cm2/V-s

33. When temperature is increased from room temperature the resistivity of an intrinsic

semiconductor

A. decreases

B. increases

C. becomes zero

D. does not change

11

34. The diamond crystal structure is formed by

A. two interlaced bcc unit cells

B. three interlaced fcc unit cells

C. three interlaced bcc unit cells

D. two interlaced fcc unit cells

35. The longest wavelength that can be used to analyze the NaCl crystal planes of spacing

d = 2.82 Å in the first order is

A. 1.45 × 10-10

m

B. 2.82 × 10-10

m

C. 5.64 × 10-10

m

D. 4.64 × 10-10

m

36. If the Fermi energy is 3kT above the edge of the conduction band, then the probability of

finding an electron at the Fermi energy EF is

A. 1.0

B. 0.3

C. 0.7

D. 0.5

37. The density of impurity atoms that must be added to intrinsic silicon to convert it to

10-1

Ω m p-type silicon with hole mobility 0.05 m2/V is

A. 1.25 × 1017

/m3

B. 1.25 × 1021

/m3

C. 1.25 × 1021

/cm3

D. 1.25 × 1017

/cm3

38. In case of intrinsic semiconductors the Fermi level EF lies exactly in the center of the

forbidden energy gap Eg when

A. the effective mass of a hole is equal to the effective mass of the free electron

B. the effective mass of a hole is less than the effective mass of the free electron

C. the effective mass of a hole is greater than the effective mass of the free electron

D. the charge of a hole is equal to charge of an electron

39. In a typical Hall effect experiment, if a 1.6 mm thick sample of n-type germanium

with donor density 1021

/m3 is placed in a magnetic field of 5 weber/m

2, the Hall voltage

developed for a current density of 500 A/m2 is

A. 40 mV

B. 35 mV

C. 10 mV

D. 25 mV

12

40. When a p-n junction diode is forward biased

A. the depletion region is reduced and barrier height is increased

B. both the depletion region and barrier height are reduced

C. the depletion region is increased and barrier height is reduced

D. both the depletion region and barrier height are increased

41. In a p-n junction, the depletion layer consists of

A. immobile ions

B. protons

C. electrons

D. mobile ions

42. An ideal diode should have

A. zero resistance in forward bias as well as reverse bias

B. zero resistance in forward bias and an infinitely large resistance in reverse bias

C. infinitely large resistance in reverse bias

D. infinitely large resistance in forward as well as reverse bias

43. The minimum gate current which can turn an SCR on is called

A. holding current

B. trigger current

C. junction current

D. break over current

44. A UnijunctionTransistor (UJT) has

A. one emitter and two bases

B. two emitters and one base

C. one emitter and one base

D. two emitters and two bases

45. What are the bias conditions of the emitter-base and collector-base junctions

respectively for a BJT to operate as an amplifier?

A. Reverse; Forward

B. Reverse; Reverse

C. Forward; Reverse

D. Forward; Forward

13

46. To make a good non-rectifying contact between a metal and n-type semiconductor,

A. the semiconductor should be lightly doped

B. the work function of metal should be greater than the work function of

semiconductor

C. the work function of metal should be lower than the work function of

semiconductor

D. the metal should have a high Schottky barrier height

47. For an ideal JFET, when VDS is increased beyond the pinch off point, the drain current

A. remains constant

B. increases

C. decreases

D. first decreases and then increases

48. If the forward current–voltage characteristic of a p-n junction diode has a slope of 50

mA/V at a desired point then the approximate incremental resistance of the diode is

A. 20 Ω

B. 50 Ω

C. 10 Ω

D. 35 Ω

49. In an n-channel enhancement MOSFET, at a fixed drain voltage

A. the drain current has a finite value at zero gate voltage and it increases with

applied negative gate voltage.

B. the drain current is zero at zero gate voltage and it increases with the applied

positive gate voltage.

C. the drain current is maximum at zero gate voltage and it decreases with applied

negative gate voltage.

D. the drain current is maximum at zero gate voltage and it decreases with positive

gate voltage.

50. If a transistor has 97.0 then the value of β is

A. 32.33

B. 0

C. 1

D. 2.94

14

32V

6A 24Ω

8Ω I2 RL 14Ω

51. Consider the following statements associated with reciprocal two port networks:

1. Z12 = Z21 2. Y12 = Y21 3. h12 = h21 4. AD-BC =1

Which of the statements given above are correct ?

A. 1,2,3

B. 1,2,4

C. 1,3,4

D. 2,3,4

52. In an RLC circuit )6

5314sin(20)(

ttv and )

3

2314sin(10)(

tti . The power

factor of the circuit is

A. 0.5

B. 0.707

C. 1.0

D. 0.866

53. The value of R in the circuit when the current is zero in the branch AB is

A. 60 Ω

B. 20 Ω

C. 40 Ω

D. 30 Ω

54. If each branch of a delta circuit has an impedance Z3 , then each branch of the

equivalent Y circuit has an impedance

A. 3

Z

B. 3Z

C. 3 3Z

D. 3

Z

55. The current through RL for the network shown in the figure is

A. 6 A

B. 3 A

C. 4 A

D. 9 A

12 V

10Ω5Ω

5Ω

10Ω

20Ω

R

A B

10Ω

15

56. The inductance of a coil in which the current increases linearly from 0 to 0.2 A in a time

interval of 0.3 sec producing a voltage of 10 V is

A. 9 H

B. 10 H

C. 15 H

D. 1.5 H

57. The differential equation for the current in the circuit of the figure shown is

A. 2

22 2 ( ) sin( )

d i dii t t

dt dt

B. 2

22 2 ( ) cos( )

d i dii t t

dt dt

C. 2

22 2 ( ) cos( )

d i dii t t

dt dt

D. 2

22 2 ( ) sin( )

d i dii t t

dt dt

58. An inductor of 5 mH will have the same reactance as a capacitor of 0.1 μF at an

approximate frequency of

A. 10 kHz

B. 14 kHz

C. 7 kHz

D. 0.7 kHz

59. A coil having R = 120 Ω and L = 24 H is connected across a 12 V battery. The time

constant and the current after 0.2 second is

A. 5 sec, 100 mA

B. 0.5 sec, 63 mA

C. 0.2 sec, 63 mA

D. 0.2 sec, 100 mA

60. While drawing the Thevenin circuit, Vth equals the

A. short circuit terminal voltage

B. net voltage available in the circuit

C. EMF of battery nearest to these terminals

D. open circuit terminal voltage

sin t

2Ω

1F

2H

16

61. In the circuit shown in the figure, the value of load resistance RL which would extract

maximum power from the circuit is

A. 6.0 Ω

B. 5.4 Ω

C. 6.5 Ω D. 8.0 Ω

62. A certain current source has the values IS = 4 µA and RS = 1.2 MΩ. The values for an

equivalent voltage source are

A. 4.8 V, 1.2 MΩ

B. 4.8 V, 4.8 MΩ

C. 1 V, 1.2 MΩ

D. 4.8 µV, 1.2 MΩ

63. Find the current through the resistance R2 for the circuit shown in the figure.

A. 0 A

B. 1.5 A

C. 2.5 A

D. 5 A

64. A 12 V source has an internal resistance of 90 Ω. If a load resistance of 10 Ω is

connected to the voltage source, the load power is

A. 188 mW

B. 0 W

C. 44 W

D. 144 mW

65. A capacitor is charged by a constant current of 2 mA and results in a voltage increase of

12 V in a 10 sec interval. The value of capacitance is

A. 0.75 mF

B. 1.33 mF

C. 0.6 mF

D. 1.67 mF

66. In a transistor a change of 8.0 mA in the emitter current produces a change of 7.8 mA in

the collector current. What change in the base current is necessary to produce the same

change in the collector current?

A. 200 µA

B. 150 µA

C. 50 µA

D. 100 µA

RL

3Ω

36V 6Ω

4Ω

17

67. Resonance frequency of a parallel LC resonance circuit is

A. LC

1Hz

B. LC2

1Hz

C. LC Hz

D. LC

2Hz

68. A chopper has a supply voltage of 200 V dc, ON time of 30 ms and OFF time of 10 ms.

The duty cycle and average dc output voltage are

A. 0.50 and 100V

B. 0.50 and 150V

C. 0.75 and 150V

D. 0.75 and 100V

69. A negative feedback amplifier has an internal gain A=100 and feedback factor =0.1. Its

gain with feedback will be

A. 0.11

B. 9.09

C. 11.1

D. 109.9

70. An ideal current source is one whose internal resistance is

A. zero

B. very high

C. very low

D. Infinite

71. The figure shown below represents an op amp circuit. If R1 = infinity and R2 = 0, then

the circuit is

A. an inverting amplifier with ideal gain infinity

B. an inverting amplifier with Vo = 0

C. a non inverting amplifier with Vo = Vin

D. a non inverting amplifier with ideal gain infinity

18

72. A square wave input of 8V peak-to-peak magnitude and frequency 2 MHz is applied to

a voltage follower, which produces the triangular output as shown in the figure. What is

its slew rate?

A. 16 V/µs

B. 8 V/µs

C. 4 V/µs

D. 2 V/µs

73. A non-inverting op amp circuit shown in the figure has a series resistor R1 = 10 k and

a voltage gain of 20 dB. The value of the feedback resistor R2 is

A. 90 k

B. 76 k

C. 10 k

D. 100 k

74. In the circuit shown in the figure, the switch is initially closed for 0.5 minutes and then

opened. What is the input voltage if the output voltage is initially 0 and –5.4 V after the

switch is opened ?

A. 5.4 V

B. -5.4 V

C. 1.8 V

D. 2.7 V

75. A 230 V – 0 – 230 V input voltage is connected to a full wave rectifier as shown in the

figure. The value of Irms across the 1 kΩ load is

A. 325.5 mA

B. 207 mA

C. 115 mA

D. 230 mA

76. Given the op amp configuration in the figure, the value of Rf required to produce a

closed loop voltage gain of 100 is

A. 110 kΩ

B. 480 kΩ

C. 220 kΩ

D. 440 kΩ

V0

+2V

-2V

t

0.5 µs 0.5 µs

19

77. The maximum peak output voltage obtainable from a741 op-amp circuit with a 100 KHz

frequency (SR = 0.5V / µs) is

A. 0.79 V

B. 0.25 V

C. 0.95 V

D. 0.40 V

78. For a JFET with IDSS = 15mA and Vgs(off) = -5 V, the drain current for Vgs = -2V is

A. 58.8 mA

B. 29.4 mA

C. 9.6 mA

D. 5.4 mA

79. If (11X1Y)8 = (12C9)16, then the values of X and Y are

A. 3 and 1

B. 5 and 7

C. 7 and 5

D. 1 and 5

80. In an 8085 microprocessor, the numbers are represented in signed 2's complement form

as P = 11101101 and Q = 11100110. If Q is subtracted from P, the value obtained in

signed 2's complement form is

A. 100000111

B. 00000111

C. 11111001

D. 011111001

81. An analog voltage of 3.4 V is converted into a 8-bit digital form by an A/D converter

with the reference voltage of 5 V. The digital output is

A. 11110001

B. 10101110

C. 10011001

D. 10110111

82. A bistable multi-vibrator that functions as a voltage comparator with hysteresis is called

A. D Flip Flop

B. Schmitt Trigger

C. T Flip Flop

D. J-K Flip Flop

20

83. The Figure of Merit of a logic family is given by

A. Gain Bandwidth Product

B. (Propagation Delay Time) x (Power Dissipation)

C. (Fan Out) x (Propagation Delay time)

D. (Noise Margin) x (Power Dissipation)

84. The shift register shown in the figure is initially loaded with the bit pattern 1010.

Subsequently the shift register is clocked, and with each clock pulse the pattern gets

shifted by one bit position to the right. With each shift, the bit at the serial input is

pushed to the left most position (MSB). After how many pulses will the content of the

shift register become 1010 again?

A. 15

B. 3

C. 7

D. 11

85. The circuit shown below is functionally equivalent to which one of the following?

A. OR Gate

B. EX-NOR Gate

C. EX-OR Gate

D. NAND Gate

86. The circuit given below is that of a

A. Mod-5 Counter

B. Mod-7 Counter

C. Mod-8 Counter

D. Mod-10 Counter

87. The logic circuit realized by the circuit shown in the figure will be

A. A C

B. B C C. B C

D. A C

21

88. The octal form of the decimal number is

A. 231.42

B. 231.41

C. 231.40

D. None of the above

89. 10’s Compliment of the number 012398 is

A. 987601

B. 087602

C. 987602

D. 087601

90. The simplified form of the Boolean function ))(( BABA is

A. B

B. 1

C.

D. A

91. A logic circuit that gives a HIGH output for both inputs HIGH or both inputs LOW is

A. an Ex-NOR gate

B. an OR gate

C. an Ex-OR gate

D. a NAND date

92. For the Karnaugh map given below, the simplified Boolean function is

A.

B.

C.

D.

93. The 8-input XOR circuit shown has an output of Y = 1. Which input combination below

(ordered A – H) is correct?

A. 10111000

B. 11100111

C. 10111100

D. 00011101

22

94. Which of the following flags in 8086 microprocessor get affected by the instruction

CMP ?

A. Trap Flag

B. Carry Flag

C. Parity Flag

D. Sign Flag

95. Consider the following instructions executed in the 8086 microprocessor

PUSH AX; AX 40 H in it

PUSH BX; BX 18 H in it

POP AX;

POP G

The value stored in G will be

A. 28 H

B. 12 H

C. 40 H

D. 68 H

96. Which of the following instructions of an 8086 microprocessor uses the content of a CX

register as a counter?

A. LOOP

B. LOCK

C. LDA

D. CALL

97. In a 8086 microprocessor, if the content of the code segment register is 1FAB and the

content of the IP register is 10A1, then the effective memory address is

A. 1FBC0

B. 30AC

C. FDB5

D. 20B51

98. Which one of the following interrupts is both level and edge sensitive?

A. RST 7.5

B. RST 6.5

C. TRAP

D. INTR

23

99. Which one of the following modes is required for 8253 to generate a square wave?

A. MODE 1

B. MODE 3

C. MODE 2

D. MODE 4

100. The interface chip used for data transmission between 8086 and a 16-bit ADC is

A. 8251

B. 8253

C. 8255

D. 8259

101. The 8086 and 8253 run at 6 MHz and 1.5 MHz respectively. The number of T-states

required to generate a square wave of period 1 ms is

A. 1500 states

B. 3000 states

C. 6000 states

D. 1000 states

102. After the following instruction is executed in a 8086 microprocessor

LOAD X

MULT Y

STORE T1

LOAD Z

ADD Y

ADD T1

STORE R

A. R = X+XY+Z

B. R = X+Y+XZ

C. R = XY+Y+Z

D. R = XY+Y+XZ

103. To have multiprocessing capabilities of the 8086 microprocessor, the pin connect to the

ground is

A. MXMN / with logic 1

B. ALE

C. INTR

D. MXMN / with logic 0

24

104. By which of the following ways can a microprocessor come out of the HALT state?

A. When HOLD line is logical 1

B. When the interrupt occurs and the interrupt system has been enabled

C. When both A and B are true

D. When either A or B are true

105. In the instruction FADD, F stands for

A. Far

B. Floppy

C. File

D. Floating

106. What will be the contents of register AL after the following has been executed ?

MOV BL,8C

MOV AL, 7E

ADD AL,BL

A. 0A and carry flag is reset

B. 0A and carry flag is set

C. 6A and carry flag is set

D. 6A and carry flag is reset

107. READY pin of a microprocessor is used

A. to introduce wait states

B. to indicate microprocessor is ready to receive inputs

C. to indicate microprocessor is ready to receive outputs

D. to provide direct memory access

108. Pseudo instructions are basically

A. false instructions

B. instructions that are ignored by the microprocessor.

C. instructions that are treated like comments

D. assembler directives

109. A rectangular waveguide of internal dimensions cm 4a , cm 3b is to be operated in

the TE11 mode. The minimum operating frequency is

A. 6.0 GHz

B. 3.75 GHz

C. 5.0 GHz

D. 6.25 GHz

25

110. For a Hertz dipole antenna, the half power beam width in the E-Plane is

A. 360ο

B. 180ο

C. 45ο

D. 90ο

111. The electric field of a time harmonic plane EM wave travelling in a non-magnetic,

lossless dielectric medium has an amplitude of 1 V/m. If the relative dielectric constant

of the medium is 4, the magnitude of the time averaged Poynting vector is

A. 240

1

B. 60

1

C. 30

1

D. 120

1

112. A transmission line has a characteristic impedance of 50Ω and resistance of 1.0 Ω/m. If

the line is distortionless, the attenuation constant (in Np/m) is

A. 0.002

B. 5.0

C. 500

D. 0.014

113. The power radiated by a Hertzian dipole antenna fed by a peak current 0I is given

by

2200

3

dlIP . The radiation resistance of the antenna is approximately

A. 2

2790

dl

B.

dl280

C. 2

280

dl

D. 2

80

dl

26

=1

114. A monochromatic plane wave of wavelength m 600 with electric field amplitude 0E is

incident on an air dielectric interface as shown in the figure; iE

, rE

and tE

denote the

incident, reflected and transmitted waves. If the angle of transmission .deg30t , the

angle of incidence i and incident electric field iE

are given by

A. 60 deg., )](

23

10[

0

4

e)ˆˆ(2

zxtj

i zxE

E

B. 45 deg., )](

23

10[

0

4

e)ˆˆ(2

zxtj

i zxE

E

C. 60 deg., )](

23

10[

0

4

e)ˆˆ(2

zxtj

i zxE

E

D. 45 deg. , )](

23

10[

0

4

e)ˆˆ(2

zxtj

i zxE

E

115. An electromagnetic wave is to pass through an interface separating two media with

dielectric constants ε1 and ε2 respectively. If 1 24 , the wave will be totally reflected if

angle of incidence is

A. 0ᵒ

B. 45ᵒ

C. 60ᵒ

D. 30ᵒ

116. The magnitudes of the open circuit and short circuit input impedance of a transmission

line are 100 Ω and 25 Ω respectively. The characteristic impedance of the line is

A. 25 Ω

B. 75 Ω

C. 50 Ω

D. 100 Ω

117. If 0 0

5 3 5ˆ ˆcos sin

2H t z x t z y

is the field of a plane wave

propagating in free space is. The time average power flow density is

A. 100

o

B. 100

o

C. 50

o

D. 250 o

27

118. The amplitude of the magnetic field of a plane wave propagating in a medium

characterized by =0, =0 and =40 is 2A/m. The magnitude of the electric field will

be

A. 80 V/m

B. 120 V/m

C. 60 V/m

D. 20 V/m

119. For a plane wave propagating in a lossless medium, the wavelength is 0.25 m and the

frequency is 600 MHz. The permittivity of the medium will be

A. 6

B. 3

C. 2

D. 4

120. When a EM wave propagates in a lossy dielectric medium, as the conductivity increases

the phase constant

A. decreases

B. remains unchanged

C. zero

D. increases

121. The medium 1 and 2 have relative permittivities 1 and 2, respectively, then Brewster's

angle B for a wave travelling from medium 2 to medium 1 is

A. 2

1tan

B

B. 1

2tan

B

C. 21tan B

D. 212tan B

122. If the Coulomb force acting on a charge of 10 C is yx aaF ˆ4ˆ3

N, the magnitude of

the electric field is

A. 0.5 V/m

B. 10 V/m

C. 7 V/m

D. 1.2 V/m

28

123. A coaxial cable with characteristic impedance 50 is insulated with a dielectric, whose

relative permittivity is 1.0. The phase velocity of the waves on this coaxial cable at 10

GHz will be

A. 2.71010

cm/s

B. 3.61010

cm/s

C. 31010

cm/s

D. 1.91010

cm/s

124. A current distribution gives rise to the vector magnetic potential

Wb/mˆ4ˆˆ 22 kxyzjxyiyxA

. B

at (-1, 2, 5) is

A. 2 Wb/mˆ3ˆ40ˆ20 kji

B. 2 Wb/mˆ3ˆ40ˆ20 kji

C. 2 Wb/mˆ3ˆ40ˆ20 kji

D. 2 Wb/mˆ3ˆ40ˆ20 kji

125. A dipole produces an electric field intensity of 1mV/m at a distance of 2 km. The field

intensity at a distance of 4 Km will be

A. 0.5 mV/m

B. 1 mV/m

C. 0.75 mV/m

D. 0.25 mV/m

126. If binary PSK modulation is used for transmission the required minimum bandwidth is

9600 Hz. To reduce the transmission bandwidth to 4800 Hz, the scheme to be adopted

should be

A. Minimum Shift Keying

B. Quadrature Phase-Shift Keying

C. Amplitude Shift Keying

D. Binary Frequency Shift Keying

127. If the baud rate is 400 for a QPSK signal, the bit rate in bits per second is

A. 400

B. 100

C. 800

D. 1600

128. Quadrature amplitude modulation (QAM) is a combination of

A. ASK and PSK

B. ASK and FSK

C. PSK and FSK

D. PCM and PSK

29

129. In a PCM system, if we increase the quantization levels from 2 to 8, how does the

relative bandwidth requirement vary?

A. Gets doubled

B. Remains the same

C. Gets tripled

D. Becomes eight times

130. In a receiver the input signal is 100 µV, while the internal noise at the input is 10 µV.

With amplification the output signal is 2 V, while the output noise is 0.4 V. The noise

figure of receiver is

A. 1

B. 0.2

C. 0.5

D. 2

131. An AM signal is represented by V )102cos()500sin420()( 5tttx . The

modulation index is

A. 20

B. 4

C. 0.2

D. 10

132. Four voice signals, each limited to 4 kHz and sampled at Nyquist rate are converted into

binary PCM signal using 256 quantization levels. The bit transmission for the time-

division multiplexed signal will be

A. 256 kbps

B. 64 kbps

C. 8 kbps

D. 512 kbps

133. An antenna has directivity of 100 and operates at 150 MHz. The maximum effective

aperture is

A. 2m 50

B. 2cm 10

C. 2m 100

D. 2cm 1

30

134. What is the unmodulated carrier power when Pout= 50 W at 100% modulation and

internal loss of the modulator is 10 W?

A. 60 W

B. 100 W

C. 150 W

D. 40 W

135. In an AM signal, the peak antenna current is 12 A and the minimum current is 4 A. The

percent modulation is

A. 30%

B. 40%

C. 50%

D. 100%

136. A signal of maximum frequency of 10 KHz is sampled at Nyquist rate. The time interval

between the two successive samples is

A. 50 µs

B. 100 µs

C. 20 µs

D. 5 µs

137. For attenuation of high frequencies we should use

A. Series Capacitance

B. Inductors

C. Resistance

D. Shunt Capacitance

138. A 400W carrier is amplitude modulated with modulation index m=0.75. The total power

of AM wave is

A. 400W

B. 588W

C. 650W

D. 512W

139. Frequency shift keying is used mostly in

A. Telephony

B. Telegraphy

C. Satellite Communication

D. Radio Transmission

31

140. An FM signal represented by )]10sin(2102sin[ 2000)( 48 tttx is applied to a

antenna. Its transmitted power is

A. 40 kW

B. 20 kW

C. 80 kW

D. 10 kW

141. The reason for using non-uniform quantization in PCM system is that it

A. decreases quantization noise for low signal levels

B. simplifies the quantization process

C. leads to reduced transmission band width

D. increases the maximum signal to quantization noise ratio

142. Which of the following is necessarily associated with flat-top sampling

A. Aliasing effect

B. Aperture effect

C. Natural sampling

D. Instantaneous sampling

143. A pre-emphasis circuit provides extra noise immunity by

A. boosting the low frequencies

B. amplifying the higher audio frequencies

C. pre-amplifying the whole audio band

D. converting the phase modulation to FM

144. For a given date rate, the BW B0, of OOK or ASK signals and BW Bp of PSK signal are

related as

A. Bp = B0

B. Bp = 0.5B0

C. Bp = 2B0

D. Bp < B0

145. Voice frequency range in a telephone system is restricted to about

A. 0 to 4000 Hz

B. 0 to 3400 Hz

C. 300 to 3400 Hz

D. 100 to 3600 Hz

32

146. A digital meter has a 3½-digit display and an accuracy of ± (0.6+1). The measurement

accuracy for a 20 volt dc voltage will be

A. ± 1.1 %

B. ± 11.1 %

C. ± 2.2%

D. ± 22.2%

147. A 10 mA current is flowing through an 10%820 resistor. This current is measured

using a 25 mA range analog meter that has %2 accuracy on the full scale. The

percentage error in the calculated power is

A. ± 12 %

B. ± 5 %

C. ± 20 %

D. ± 10 %

148. A basic Q-meter circuit has 100 mV ac supply, R=5 and XL=XC=100 at resonance.

The Q factor of the coil is

A. 100

B. 200

C. 10

D. 20

149. A pulse waveform with a 10 ns rise time is applied to an oscilloscope that has an upper

cutoff frequency of 7 MHz, the displayed rise time will be

A. 51 ns

B. 21 ns

C. 70 ns

D. 60 ns

150. A permanent magnet movement coil instrument with 100 A FSD and a 1 k coil

resistance is to be used in an ammeter. What will be the shunt resistance for a FSD of

100 mA?

A. 10.01

B. 100.1

C. 0.1001

D. 1.001

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FOR ROUGH WORK

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FOR ROUGH WORK

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