MH SET 2013: 17 February, Paper II, Electronic Science
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Electronic Science
Paper II
Time Allowed : 75 Minutes] [Maximum Marks : 100
Note : This Paper contains Fifty (50) multiple choice questions. Each question
carries Two (2) marks. Attempt All questions.
1. For a reverse biased diode there 3. Channel is established during the
is : fabrication process itself of the
following MOSFET :
(A) No current at all
(A) Depletion mode MOSFET
(B) Very small current due to
(B) Enhancement mode MOSFET
minority carriers
(C) n-Channel enhancement
(C) A large current MOSFET
(D) Some current due to majority (D) p-channel enhancement
MOSFET
carriers
4. The capacitor filter is characterized
2. The gain of a certain amplifier
by :
decreases by 8 dB when the
(A) Poor voltage regulation and
frequency is reduced from 1 kHz to high peak current capability
10 Hz. The roll-off is : (B) Poor voltage regulation and low
(A) –8 dB/decade peak current capability
(C) Good voltage regulation and
(B) –4 dB/decade
high peak current capability
(C) –4 dB/octave
(D) Good voltage regulation and
(D) –8 dB/octave low peak current capability
1 [P.T.O.
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5. Substitutional impurities that 7. If a network contains B branches
and N nodes, then the number of
replaces the silicon in a silica
mesh current equations would
polyhedron are called as :
be :
(A) Network modifier (A) B – N – 1
(B) Interstitial impurities (B) B – (N – 1)
(C) N – (B – 1)
(C) Network formers
(D) (B + N) – 1
(D) Non-bridging oxygen ion
8. Laplace transform of t is :
producers
(A) 1/s
6. Superposition theorem is (B) s
not applicable to networks 1
(C)
s2
containing :
(D) s 2
(A) Non-linear elements 9. z-transform of δ(n) is :
(A) 1
(B) Dependent voltage sources
(B) zk
(C) Dependent current sources
(C) z–k
(D) Transformers (D) k
2
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10. Which of the statement is correct for 12. Current output of a Zener diode
1
? based voltage regulator :
s2
(A) This has two zeros at origin of (A) is limited by Zener current
s-plane
(B) can be augmented with the help
(B) This has two poles at origin of
of Darlington pair
s-plane
(C) is limited by load
(C) This has complex conjugate
poles on imaginary axis of (D) can not be changed
s-plane 13. The main advantages of a
(D) This has two poles at infinity differential amplifier over single
of s-plane
stage amplifier are :
11. An input of a.c. frequency f is fed
(A) Stability and low noise
to a half wave rectifier. The main
component frequency in the ripple (B) Stability and greater
will be : amplification
(A) f (C) CMRR is low and gain is
(B) 2f higher
(C) f/2 (D) CMRR is high and gain is
(D) ∞ (Infinity) higher
3 [P.T.O.
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14. For an op-amp based integrator, a 16. The maximum number of
feedback capacitor is 1 µF and the
input resistance is 100 kΩ. The input 3-input gates in a 16 pin IC will
voltage is V1(t). Then the output
be :
is :
t (A) 2
(A) − ∫ V1 dt
0
(B) 3
t
(B) − 10 ∫ V1 dt
0
(C) 4
t
1
10 ∫0 1
(C) − V dt
(D) 5
t
(D) ∫ V1dt 17. Which one of the following is an
0
15. The output of a noisy level detector example of a counter with a
is fluctuating with + 0.5 volts. An
truncated modulus ?
Schmitt trigger is to be used for the
triggering. The upper level and
(A) Modulus 8
lower level for trigger must be
separated by at least :
(B) Modulus 32
(A) 0.5 V
(B) 1 V (C) Modulus 16
(C) between 0.5 and 1 V
(D) Modulus 14
(D) between 0 and 0.5 V
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18. The group of bits 10110101 is 20. The 74LS83A is an example of a
4-bit parallel adder. To expand this
serially shifted (right most bit first)
device to an 8-bit adder, you
into 8-bit parallel output shift
must :
register with an initial state of
(A) Use four adders with inter-
11100100. After two clock pulses, the connections
register contains : (B) Use two adders and connect the
sum outputs of one to the bit
(A) 01011110
inputs of the other
(B) 10110101
(C) Use eight adders with inter-
(C) 01111001 connections
(D) Use two adders with carry
(D) 00101101
output of one connected to the
19. A 32-bit data word consists carry input of the other
of : 21. A digital multimeter is an example
of an embedded system for :
(A) 2 bytes
(A) Data communication
(B) 4 nibbles
(B) Monitoring
(C) 4 bytes
(C) Control
(D) 3 bytes and 1 nibble (D) Data processing
5 [P.T.O.
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24. In case of 8051 microcontrollers,
22. Which port of 8051 is ‘true
what will be the value of ‘Program
bidirectional’ ?
Counter (PC)’ after a proper power
(A) Port 0 on reset ?
(A) FFFFH
(B) Port 1
(B) 0007H
(C) Port 2
(C) Random Value
(D) Port 3
(D) 0000H
23. Which is the addressing mode 25. For the 8051 microcontroller, name
the register which acts as
for the instruction MOV A,
the ‘Receive’ and ‘Transmit’
@ RO ?
buffer in serial communication
(A) Direct operation :
(A) SCON
(B) Indirect
(B) PCON
(C) Immediate
(C) SBUF
(D) Indexed
(D) Accumulator
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26. What will be the output of the
28. Setting up of baud rate is a must
following C program module ?
main( ) for :
{
(A) mathematical expression
int i, j;
evaluation
for(i=0; i < =10, i++)
{ j = 5 * i; (B) parallel port operations
j++;
(C) sound generation
}
print ("%d %d", i, j); (D) serial port operations
(A) 10 51
29. Dummy variables are used
(B) 11 50
(C) 10 50 to :
(D) 11 51
(A) restrict their scope within a
27. What of the following header file
function
must be included in a C code while
drawing some diagrams on the
(B) allow transfer of values between
screen ?
(A) stdio.h the functions
(B) graphics.h
(C) expand list of variables
(C) math.h
(D) string.h (D) fix the constants
7 [P.T.O.
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30. The evaluation of the following 32. A transmission line with z0 =100 Ω
is connected to a load of 400 Ω
integer expression :
through another transmission line
((5+3/2) +7/4)/3
of length λ/8 and characteristic
result into : impedance of 200 Ω. The reflection
coefficient is :
(A) 2
(A) 1
(B) 0
(B) i
(C) 1
(C) –i
(D) 3
(D) –1
31. It is observed that for a load, the
33. In a rectangular waveguide with
voltage first minimum occurs at a
dimensions 4 cm × 1 cm, condition
distance of λ/8 from the load. If
for single lowest possible
|ρ|=1, the reflection coefficient
mode transmission is satisfied
is :
for :
(A) 1
(A) λ = 0.5 cm
(B) i
(B) λ = 4 cm
(C) –i
(C) λ = 1 cm
(D) 1+i
(D) λ = 6 cm
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34. Measured beam solid angle for an 36. Assume that a binary PCM singal,
with polar NRZ signalling, is passed
antenna is π. The gain turns out to
through a communication system
be 3. The efficiency factor for
with a raised cosine roll-off filtering
antenna is : characteristics and the the roll factor
is 0.25. The bit rate of the PCM
(A) 0.5
signal is 64 k bits/sec. The absolute
(B) 0.75 bandwidth of the filtered PCM
signal is ....................kHz.
(C) 0.8
(A) 10
(D) 0.9
(B) 20
35. In microwave tunnel diodes :
(C) 30
(A) p is lightly doped but n is highly (D) 40
doped 37. .............of the following is often called
as linear modulation.
(B) p and n are lightly doped
(A) AM
(C) p and n are heavily doped
(B) FM
(D) p is heavily doped by n is lightly
(C) PM
doped (D) FSK
9 [P.T.O.
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38. ................is an example of a feedback 40. The power level in dBm for
a signal level of the 10 mW
FM dimodulator.
is :
(A) Slope detector
(A) 10 dBm
(B) Envelope detector (B) 20 dBm
(C) 1 dBm
(C) Linearity discriminator
(D) 1/10 dBm
(D) Phase lock loop
41. Which of the following is not a
39. For 16-PSK and a transmission desired characteristics of a power
system with a 10 kHz bandwidth, the electronic switching device ?
(A) zero conduction and switching
maximum bit rate is :
losses
(A) 16,000 bps
(B) instant turn-on and turn-off
(B) 10,000 bps times
(C) high leakage current
(C) 40,000 bps
(D) ability to withstand current
(D) 20,000 bps
overloads
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42. A typical uninterruptible 44. The reason for use of optical
power supply system would fibers in communication system
require : is :
(A) DC to DC converter (A) High attenuation
(B) Inverter (B) Low flexibility
(C) Chopper (C) High noise
(D) Commutator (D) High bandwidth
43. A stepper motor is basically known
45. Which device among the following
for :
will have highest sensitivity ?
(A) High holding torque
(A) Photodiode
(B) High speed operation
(B) Phototransistor
(C) Synchronous control
(C) APD
(D) AC drive
(D) LDR
11 [P.T.O.
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46. A LVDT has : 48. A causal discrete time system is
stable if the poles of the transfer
(A) One primary coil and one
function lie :
secondary coil
(A) within the unit circle
(B) Two primary coils and two (B) on the unit circle
secondary coils (C) out side the unit circle
(D) any where over the circle
(C) One primary coil and two
49. Feedback control systems are
secondary coils
(A) Low pass filters
(D) Two primary coils and one
(B) High pass filters
secondary coil
(C) Band pass filters
47. An increase in pH value above 7.0
(D) Band reject filters
indicates : 50. A microphone is classified as a
............transducer
(A) increasing basicity
(A) Thermal
(B) decreasing basicity
(B) Magnetic
(C) increasing alkalinity
(C) Acoustical
(D) decreasing alkalinity (D) Optical
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ROUGH WORK
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ROUGH WORK
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Source: Savitribai Phule Pune University. Question paper published by Savitribai Phule Pune University.