Exam Details
| Subject | electronics and communication engineering | |
| Paper | ||
| Exam / Course | ||
| Department | ||
| Organization | indian space research organisation | |
| Position | ||
| Exam Date | 2009 | |
| City, State | , |
Question Paper
1. If a counter having 10 FFs is initially at what count will it hold after 2060 pulses?
000 000 1100
000 0011100
000 0011000
000 000 1110
2. A memory system of size 16 K bytes is required to be designed using memory chips which have 12 address lines and 4 data lines each. Then the number of such chips required to design the memory system is
a)2
b)4
c)8
16
3. Consider the following program for 8085 XRAA LXIB,0007H LOOP: DCXB JNZLOOP The loop will be executed 8 times 7 times once infinite times
4 A certain JK FF has tpd=12 ns. The largest MOD counter that can be constructed from such FFs and still operate up to 10 MHz is 16 256 8 128
5 Convolution of with impulse function is equal to
6 The purpose of a Cassegrain feed in a parabolic reflector antenna is to Achieve higher antenna gain Reduce the antenna size Reduce the beamwidth Ease of locating the feed at convenient point
..
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L <".f
7 A transfer function has pole-zero plot as
1m h·
shown in the figure. Given that the steady
state function gain is the transfer function will be given by .
I I I
Re
5(s b)
S2 S2 5
10(s
8 The im edance of a series RLC circuit is R2 +XZ (XL +Xc
9 The advantage of1C/4 QPSK compared to conventional QPSK is n/4 QPSK requires less bandwidth compared to conventional QPSK n/4 QPSK produces lower envelope variation compared to conventional QPSK n/4 QPSK receiver design is simple compared to conventional QPSK There is no advantage
10 A moving coil iron ammeter may be compensated for frequency errors by Series inductance Shunt resistance Series resistor Shunt capacitor
11 Find the value ofVo in the figure.
112V b) V 0V V
12 What is the approximate skin depth in copper at 100 MHz? 0.1 micron 10 microns 10 mm 100 mm
13 While designing a low noise amplifier, what is the importance of the noise resistance ofa transistor? It gives the effective impedance offered by the input with respect to noise current It defines the criterion for conjugate matching of input impedance It tells us the resistance that same amount of noise at room temperature It teUs how rapidly the noise figure increases as we move away from the optimum source impedance
... Unattenuated radiation field at the surface of the earth of a monopole will exist if the earth surface is Lossy dielectric Perfect insulator Perfectly conducting None of these
15 Given that
A3
Evaluate 11A-101
Null matrix Identity matrix
-41 None of the above
16 lim x log sin(x) is a)0 Y2 c)1 d)2
17 A 12 bit ADC is operating with a 1 J.l.S clock period and the total conversion time is seen to be 14 J.l.S. The ADC must be of Flash type Counting type Integrating type Successive Approximation type
18 Which of the following types of devices is not field programmable? FPGA ASIC CPLD d)PLD
19 Which is the correct order of different process steps for a typical FPGA design? Functional simulation, Synthesis, Place Route, Timing Verification Functional simulation, Timing Verification, Synthesis, Place Route Timing Verification, Synthesis, Functional simulation, Place Route Synthesis, Functional simulation, Timing Verification, Place Route
20 The theoretical dividing line between Reduced Instruction Set computing (RISC) microprocessor and Complex Instructions Set Computing (CISC) microprocessor is Instruction execution rate to be one instruction per clock cycle Number of address and data lines N umber of pins in the chip None of the above
21 In a pulsed radar, the peak radar transmitter power is increased by a factor of81 keeping aU other radar parameters unchanged. The maximum range capability of the radar increases by a factor of a)81 b)9 c)27 d)3
22 A radar transmitter has a PRF of 1500 PPS and a pulse width of 1 micro second. Its duty cycle is 0.0075 0.015 0.0015 0.00075
23 Which ofthe following technology results in least power dissipation?
CMOS EeL TTL NMOS
24 A power MOSFET is a .
Current controlled device Frequency controlled device
Voltage controlled device None of the above
25 The advantage ofdifferential PSK (DPSK) over coherent PSK is DPSK requires less bandwidth compared coherent PSK DPSK receiver design is simple compared to coherent PSK DPSK Bit Error rate is lower than coherent PSK For same bandwidth, DPSK bit rate is higher compared to coherent PSK
26 An ideal current meter should have Zero resistance Finite resistance Infinite resistance Very large resistance 27 For the network shown in the figure is the input and is the output. The transfer
function
Vies)
ofthe network is
C
RCs 2 +LCs
Cs
RCs 2 +LCs
R L
t Viet) 1 J c
C LCs 2 +RCs Cs LCs2 +RCs+1
28 The length of a lossy shorted stub is 1/32 Iv. What,will be the nature ofits input impedance? A low inductive reactance in series with a low resistance A low capacitive reactance in shunt with a high resistance A high capacitive reactance in series with a low resistance A high inductive reactance in series with a low resistance
29 Refer to the circuit in the figure. Which of the following statements is NOT true about 2000hrn this circuit?
It is a low pass filter b) It has a finite attenuation at infinite
frequency
Its phase shift varies monotonically with It has one pole and one zero
the frequency
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30 Which ofthe following is thecorrect continuity equation:
V_J=Op b)
V-J aE
V-J
at
2
31 are the roots of the equation x x 1 O. Then a3n is
32 A point moving in the complex plane satisfies the following relation Z2 Z*2 where stands for the complex conjugate of z. The difference of the distances ofthe moving point from -and is
33 The greatest negative numberwhich can be stored in a computer that has 8-bit word length and uses complement arithmetic is -256 -255 -128 -127
34 Which of the following ADCs uses over sampling in its operation Sigma -delta ADC Counter ramp convertor Successive Approximation Register ADC Flash Convertor
35 A mealy state machine's output depends on State and outputs Inputs State State and inputs
36 The of the T-FF is given by =TQ =TQ =TQ =TQ+QT
37 Percentage modulation of an AM wave having a power content of 8 KW at carrier frequency and 2 KW in each of its side bands is b)70 c)100%
38 Approximateequivalentnoisetemperature(deg.K)ofanamplifierwithanoisefactorof1.04 is 301.6 11.6 278.4 5.8
39 A differential amplifier is used in the input stage of Op-Amps to achieve very high
open -loop gain bandwidth slew rate CMRR
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13
ELECTRONICS AND COMMUNICATION ENGINEERING
40 Which two-port parameters are best suited for analyzing a series-shunt feedback circuit?
Z-Parameters H-Parameters V-Parameters S-Parameters
41 S t=O
L
20V
For the circuit shown in the figure, the switch is closed at t=O. After some time when the current in the inductor was 6A, the rate of change of current through the inductor was 4AJsec. The value ofthe inductor is
0.5 H 1.5 H 1.0 H Indeterminate
42 120K Q
40KQ
L
1V
Va
80KQd
2V
120KQ
3V
In the circuit shown in the above figure, the value of output Vo is -9V -6V
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ELECTRONICS AND COMMUNICATION ENGINEERING
43 The characteristics equation of a closed loop control system is given as S2 4s 16 . The resonant frequency in radian/sec of the system is a)2 2f3 4 2..fi 44 Which point in the Smith
N.B. --Reference Zo is son
Chart is labeled with the
WRONG impedance?
lO+jlO 50+j50 200-j200 25-j50
45 Ifa line is terminated in an open circuit, the VSWR is 00 b)O c)l
46 Unit of relative permeability is Henry/meter Henry Henry-meter It is dimensionless
47 [tan2x] standsfor greatest integerfunction) continuous at x 0 limit does not exist as x tend to 0 1 not derivable at x 0
48 Number of real values of ib)l/n I1n is None the above
49 A 5 bit DAC has a current output. For a digital input of 10100, an output current of 10 rnA is produced. What will be the output current for a digital input of 11101?
14.5 mA 10 mA 100 mA Not possible to calculate
50 The ethernet protoa) CSMAfCA col uses SCPC CSMAfCD Slotted ALOHA
51 A micro controller differsfrom a microprocessor in terms of I/O interfaces and instruction decoding Memory configuration and I/O interfaces Data bus width and clock speed Memory configuration and instruction decoding
52 An 8-bit microcontroller has an external RAM with the memory map from 8000H to 9FFFH. The number of bytes this RAM can store is 8193 8192 8191 8000
53 An audio frequency of 15 KHz is frequency modulated with a deviation of75 KHz. The resulting bandwidth is 180 KHz 150 KHz 210 KHz 240 KHz
54 A lkW carrier is Amplitude Modulated to a depth of 60%. The total power in the modulated carrier is a)1kW b)1.06 kW c)1.6 kW d)1.18 kW
55 3Q
The YZI parameter of the network shown in the given figure will be
.
10 OF 13
56 An inductance of 1 H is realized using air core with 100 turns. What will be the induCtance if the number of turns are doubled? 1H 0.5 H c)2 H None of these
57 An inductor of inductance 0.1 carrying current of6 Amps will store energy of
6 Joules 36 Joules 1.8 Joules 3.6 Joules
58 Acoilhasselfresistanceof50andinductanceof1 The value of Q at 1 MHz frequency is 200 100 40 None of these
59 The closed loop transfer function of a unity feedback control system is
1 2. The closed loop transfer function will have poles at
±j . d)
60 The dominant mode of propagation in microstrip line in low frequency approximation is
TMll Quasi-TEM TEM TEol
61 Consider a transmission line of characteristic impedance 50 ohms and the line is terminated at one end by +j50 ohms, the VSWR produced in the transmission line will be zero infinity
62 The divergence of magnetic flux density is
j b)P c)0 OJ
63 A straight line and a circle of radius a are given. A chord is drawn at random to this circle parallel to th_e given line. Expected length of the chord is
a)2a b)na na/2 None of the above
64 There is a function such that 1 and and is positive for all values ofx.
Then,
forallx
foraUx
foraUx
None of the above
65 Interrupt latency is the time elapsed between: Occurrence ofan interrupt and its detection by the CPU Assedion ofan interrupt and the stal't of the associated ISR Assertion of an interrupt and the completion of the associated ISR Start and completion ofassociated ISR
66 Inverse Fourier transform of signal XQoo)=211:o(00) rco(ro rco(ro+4rc) 1+cos411:t rc(1-cos4rct) 2rc(1-cos4rct) 2rc(1+cos4rct)
67 Determine the discrete-time Fourier Transform for the signal
n=O
Zj(Zsin 2ro sin 00) -Zj(2sin Zro sin 00) 2(2cos 2ro -cos 00) -2(2cos 200 -cos 00)
68 Auto-correlation of a sinusoid is
69 A source produces 4 symbols with probabilities 112,114,118,118, For this source, a practical coding scheme has an average codeword length of2 bits/symbol. The efficiency of the code is a)1 c)112 d)114
70 When signal frequency is 2000 KHz and IF is 455 KHz, the image frequency could be 2910 KHz 1645 KHz 2455 KHz 2090 KHz
71 The Q of RLC tuned circuit with source voltage V in the figure is 100 at resonant
L
R
frequency of 100 KHz,
What is the voltage VL
/vN
across inductor at
resonance?
50V
100V
12 OF 13
72 A 5V reference is drawn from the circuit shown in the figure. Zener diode of 400mWand 5V with firing current of 5mA is used. The value of Rs is
50 ohms 500 ohms
73 Find the equivalent resistance R for the network shown in the figure.
R
s
10V
75 ohms 470 ohms 200
2000
2000 1000
200 ohms 101 ohms 220 ohms 100 ohms
The Voltage across last resistor is V. All resistors are unity. Then Vs is given by 13 V 8 V 4 V None of these
75 Natural frequency of a unity feedback control system of transfer function 10
is
s(s
0.5 rad/sec 3.16 rad/sec 4.6 rad/sec None of these
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76 Which ofthe following conditions will not guarantee a distortionless transmission line? G=O Very low frequency range (R» roL, G» roC) RIL= G/C. Very high frequency range (R« roL, G« roC).
77 For a line of characteristic impedance Zo terminated in a load ZRsuch thatZR> Zo, the Voltage Standing WaveRatio (VSWR) is given by ZR/Zo b)Zo c)ZR Zol ZR
78 The beamwidth ofa reflector antenna of diameter 70 cm at 30 GHz is 3.7 degree 0.5 degree 1.1 degree 1 degree
b)1 c) None of the above
80 A man with n keys wants to open a lock. He tries his keys at random. The expected number of attempts for his success is (keys are replaced after every attempt) nl2 n -In None of the above
000 000 1100
000 0011100
000 0011000
000 000 1110
2. A memory system of size 16 K bytes is required to be designed using memory chips which have 12 address lines and 4 data lines each. Then the number of such chips required to design the memory system is
a)2
b)4
c)8
16
3. Consider the following program for 8085 XRAA LXIB,0007H LOOP: DCXB JNZLOOP The loop will be executed 8 times 7 times once infinite times
4 A certain JK FF has tpd=12 ns. The largest MOD counter that can be constructed from such FFs and still operate up to 10 MHz is 16 256 8 128
5 Convolution of with impulse function is equal to
6 The purpose of a Cassegrain feed in a parabolic reflector antenna is to Achieve higher antenna gain Reduce the antenna size Reduce the beamwidth Ease of locating the feed at convenient point
..
INDIAN
2 OF 13
ELECTRONICS AND COMMUNICATION ENGINEERING
L <".f
7 A transfer function has pole-zero plot as
1m h·
shown in the figure. Given that the steady
state function gain is the transfer function will be given by .
I I I
Re
5(s b)
S2 S2 5
10(s
8 The im edance of a series RLC circuit is R2 +XZ (XL +Xc
9 The advantage of1C/4 QPSK compared to conventional QPSK is n/4 QPSK requires less bandwidth compared to conventional QPSK n/4 QPSK produces lower envelope variation compared to conventional QPSK n/4 QPSK receiver design is simple compared to conventional QPSK There is no advantage
10 A moving coil iron ammeter may be compensated for frequency errors by Series inductance Shunt resistance Series resistor Shunt capacitor
11 Find the value ofVo in the figure.
112V b) V 0V V
12 What is the approximate skin depth in copper at 100 MHz? 0.1 micron 10 microns 10 mm 100 mm
13 While designing a low noise amplifier, what is the importance of the noise resistance ofa transistor? It gives the effective impedance offered by the input with respect to noise current It defines the criterion for conjugate matching of input impedance It tells us the resistance that same amount of noise at room temperature It teUs how rapidly the noise figure increases as we move away from the optimum source impedance
... Unattenuated radiation field at the surface of the earth of a monopole will exist if the earth surface is Lossy dielectric Perfect insulator Perfectly conducting None of these
15 Given that
A3
Evaluate 11A-101
Null matrix Identity matrix
-41 None of the above
16 lim x log sin(x) is a)0 Y2 c)1 d)2
17 A 12 bit ADC is operating with a 1 J.l.S clock period and the total conversion time is seen to be 14 J.l.S. The ADC must be of Flash type Counting type Integrating type Successive Approximation type
18 Which of the following types of devices is not field programmable? FPGA ASIC CPLD d)PLD
19 Which is the correct order of different process steps for a typical FPGA design? Functional simulation, Synthesis, Place Route, Timing Verification Functional simulation, Timing Verification, Synthesis, Place Route Timing Verification, Synthesis, Functional simulation, Place Route Synthesis, Functional simulation, Timing Verification, Place Route
20 The theoretical dividing line between Reduced Instruction Set computing (RISC) microprocessor and Complex Instructions Set Computing (CISC) microprocessor is Instruction execution rate to be one instruction per clock cycle Number of address and data lines N umber of pins in the chip None of the above
21 In a pulsed radar, the peak radar transmitter power is increased by a factor of81 keeping aU other radar parameters unchanged. The maximum range capability of the radar increases by a factor of a)81 b)9 c)27 d)3
22 A radar transmitter has a PRF of 1500 PPS and a pulse width of 1 micro second. Its duty cycle is 0.0075 0.015 0.0015 0.00075
23 Which ofthe following technology results in least power dissipation?
CMOS EeL TTL NMOS
24 A power MOSFET is a .
Current controlled device Frequency controlled device
Voltage controlled device None of the above
25 The advantage ofdifferential PSK (DPSK) over coherent PSK is DPSK requires less bandwidth compared coherent PSK DPSK receiver design is simple compared to coherent PSK DPSK Bit Error rate is lower than coherent PSK For same bandwidth, DPSK bit rate is higher compared to coherent PSK
26 An ideal current meter should have Zero resistance Finite resistance Infinite resistance Very large resistance 27 For the network shown in the figure is the input and is the output. The transfer
function
Vies)
ofthe network is
C
RCs 2 +LCs
Cs
RCs 2 +LCs
R L
t Viet) 1 J c
C LCs 2 +RCs Cs LCs2 +RCs+1
28 The length of a lossy shorted stub is 1/32 Iv. What,will be the nature ofits input impedance? A low inductive reactance in series with a low resistance A low capacitive reactance in shunt with a high resistance A high capacitive reactance in series with a low resistance A high inductive reactance in series with a low resistance
29 Refer to the circuit in the figure. Which of the following statements is NOT true about 2000hrn this circuit?
It is a low pass filter b) It has a finite attenuation at infinite
frequency
Its phase shift varies monotonically with It has one pole and one zero
the frequency
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6 OF 13
ELECTRONICS AND COMMUNICATION"ENGINEERING
30 Which ofthe following is thecorrect continuity equation:
V_J=Op b)
V-J aE
V-J
at
2
31 are the roots of the equation x x 1 O. Then a3n is
32 A point moving in the complex plane satisfies the following relation Z2 Z*2 where stands for the complex conjugate of z. The difference of the distances ofthe moving point from -and is
33 The greatest negative numberwhich can be stored in a computer that has 8-bit word length and uses complement arithmetic is -256 -255 -128 -127
34 Which of the following ADCs uses over sampling in its operation Sigma -delta ADC Counter ramp convertor Successive Approximation Register ADC Flash Convertor
35 A mealy state machine's output depends on State and outputs Inputs State State and inputs
36 The of the T-FF is given by =TQ =TQ =TQ =TQ+QT
37 Percentage modulation of an AM wave having a power content of 8 KW at carrier frequency and 2 KW in each of its side bands is b)70 c)100%
38 Approximateequivalentnoisetemperature(deg.K)ofanamplifierwithanoisefactorof1.04 is 301.6 11.6 278.4 5.8
39 A differential amplifier is used in the input stage of Op-Amps to achieve very high
open -loop gain bandwidth slew rate CMRR
INDIAN SPACE RESEARCH ORGANISATION
13
ELECTRONICS AND COMMUNICATION ENGINEERING
40 Which two-port parameters are best suited for analyzing a series-shunt feedback circuit?
Z-Parameters H-Parameters V-Parameters S-Parameters
41 S t=O
L
20V
For the circuit shown in the figure, the switch is closed at t=O. After some time when the current in the inductor was 6A, the rate of change of current through the inductor was 4AJsec. The value ofthe inductor is
0.5 H 1.5 H 1.0 H Indeterminate
42 120K Q
40KQ
L
1V
Va
80KQd
2V
120KQ
3V
In the circuit shown in the above figure, the value of output Vo is -9V -6V
Page:
OF 13
ELECTRONICS AND COMMUNICATION ENGINEERING
43 The characteristics equation of a closed loop control system is given as S2 4s 16 . The resonant frequency in radian/sec of the system is a)2 2f3 4 2..fi 44 Which point in the Smith
N.B. --Reference Zo is son
Chart is labeled with the
WRONG impedance?
lO+jlO 50+j50 200-j200 25-j50
45 Ifa line is terminated in an open circuit, the VSWR is 00 b)O c)l
46 Unit of relative permeability is Henry/meter Henry Henry-meter It is dimensionless
47 [tan2x] standsfor greatest integerfunction) continuous at x 0 limit does not exist as x tend to 0 1 not derivable at x 0
48 Number of real values of ib)l/n I1n is None the above
49 A 5 bit DAC has a current output. For a digital input of 10100, an output current of 10 rnA is produced. What will be the output current for a digital input of 11101?
14.5 mA 10 mA 100 mA Not possible to calculate
50 The ethernet protoa) CSMAfCA col uses SCPC CSMAfCD Slotted ALOHA
51 A micro controller differsfrom a microprocessor in terms of I/O interfaces and instruction decoding Memory configuration and I/O interfaces Data bus width and clock speed Memory configuration and instruction decoding
52 An 8-bit microcontroller has an external RAM with the memory map from 8000H to 9FFFH. The number of bytes this RAM can store is 8193 8192 8191 8000
53 An audio frequency of 15 KHz is frequency modulated with a deviation of75 KHz. The resulting bandwidth is 180 KHz 150 KHz 210 KHz 240 KHz
54 A lkW carrier is Amplitude Modulated to a depth of 60%. The total power in the modulated carrier is a)1kW b)1.06 kW c)1.6 kW d)1.18 kW
55 3Q
The YZI parameter of the network shown in the given figure will be
.
10 OF 13
56 An inductance of 1 H is realized using air core with 100 turns. What will be the induCtance if the number of turns are doubled? 1H 0.5 H c)2 H None of these
57 An inductor of inductance 0.1 carrying current of6 Amps will store energy of
6 Joules 36 Joules 1.8 Joules 3.6 Joules
58 Acoilhasselfresistanceof50andinductanceof1 The value of Q at 1 MHz frequency is 200 100 40 None of these
59 The closed loop transfer function of a unity feedback control system is
1 2. The closed loop transfer function will have poles at
±j . d)
60 The dominant mode of propagation in microstrip line in low frequency approximation is
TMll Quasi-TEM TEM TEol
61 Consider a transmission line of characteristic impedance 50 ohms and the line is terminated at one end by +j50 ohms, the VSWR produced in the transmission line will be zero infinity
62 The divergence of magnetic flux density is
j b)P c)0 OJ
63 A straight line and a circle of radius a are given. A chord is drawn at random to this circle parallel to th_e given line. Expected length of the chord is
a)2a b)na na/2 None of the above
64 There is a function such that 1 and and is positive for all values ofx.
Then,
forallx
foraUx
foraUx
None of the above
65 Interrupt latency is the time elapsed between: Occurrence ofan interrupt and its detection by the CPU Assedion ofan interrupt and the stal't of the associated ISR Assertion of an interrupt and the completion of the associated ISR Start and completion ofassociated ISR
66 Inverse Fourier transform of signal XQoo)=211:o(00) rco(ro rco(ro+4rc) 1+cos411:t rc(1-cos4rct) 2rc(1-cos4rct) 2rc(1+cos4rct)
67 Determine the discrete-time Fourier Transform for the signal
n=O
Zj(Zsin 2ro sin 00) -Zj(2sin Zro sin 00) 2(2cos 2ro -cos 00) -2(2cos 200 -cos 00)
68 Auto-correlation of a sinusoid is
69 A source produces 4 symbols with probabilities 112,114,118,118, For this source, a practical coding scheme has an average codeword length of2 bits/symbol. The efficiency of the code is a)1 c)112 d)114
70 When signal frequency is 2000 KHz and IF is 455 KHz, the image frequency could be 2910 KHz 1645 KHz 2455 KHz 2090 KHz
71 The Q of RLC tuned circuit with source voltage V in the figure is 100 at resonant
L
R
frequency of 100 KHz,
What is the voltage VL
/vN
across inductor at
resonance?
50V
100V
12 OF 13
72 A 5V reference is drawn from the circuit shown in the figure. Zener diode of 400mWand 5V with firing current of 5mA is used. The value of Rs is
50 ohms 500 ohms
73 Find the equivalent resistance R for the network shown in the figure.
R
s
10V
75 ohms 470 ohms 200
2000
2000 1000
200 ohms 101 ohms 220 ohms 100 ohms
The Voltage across last resistor is V. All resistors are unity. Then Vs is given by 13 V 8 V 4 V None of these
75 Natural frequency of a unity feedback control system of transfer function 10
is
s(s
0.5 rad/sec 3.16 rad/sec 4.6 rad/sec None of these
OF 13
ELECTRONICS AND COMMUNICATION ENGINEERING
76 Which ofthe following conditions will not guarantee a distortionless transmission line? G=O Very low frequency range (R» roL, G» roC) RIL= G/C. Very high frequency range (R« roL, G« roC).
77 For a line of characteristic impedance Zo terminated in a load ZRsuch thatZR> Zo, the Voltage Standing WaveRatio (VSWR) is given by ZR/Zo b)Zo c)ZR Zol ZR
78 The beamwidth ofa reflector antenna of diameter 70 cm at 30 GHz is 3.7 degree 0.5 degree 1.1 degree 1 degree
b)1 c) None of the above
80 A man with n keys wants to open a lock. He tries his keys at random. The expected number of attempts for his success is (keys are replaced after every attempt) nl2 n -In None of the above