MH SET 2011: 7 August, Paper II, Electronic Science
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AUG-38211/II
ELECTRONIC SCIENCE
Paper II
Time Allowed : 75 Minutes] [Maximum Marks : 100
Note : This Paper contains Fifty (50) multiple choice questions, each question
carrying Two (2) marks. Attempt All questions.
1. In a p-n junction, p-type region is 3. What is the function of SiO2 layer
heavily doped as a result : in MOSFET ?
(A) To provide high input
(A) depletion width extends in
resistance
n-type region
(B) To increase current concentra-
(B) depletion width extends in tion
p-type region (C) To provide high output resis-
(C) depletion width is unaffected tance
(D) To provide low output resis-
(D) depletion width reduces
tance
2. The diffusion process in a p-n
4. Compared to bipolar junction
junction device occurs due to : transistor, a JFET has :
(A) Ambient temperature (A) lower input impedance
(B) Applied voltage (B) higher input impedance and
high voltage gain
(C) Covalent bonds
(C) higher voltage gain
(D) Concentration gradient of
(D) high input impedance and low
charges voltage gain
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7. The Laplace transform of cosh ωt
5. Which of the following lithography
is :
techniques gives best resolution ?
s
(A)
s + ω2
2
(A) UV Lithography
s
(B)
s − ω2
2
(B) E-beam Lithography
ω
(C)
s + ω2
2
(C) X-ray Lithography
ω
(D)
(D) Laser Lithography s − D2
2
8. Show how many poles this network
6. Superposition theorem is valid only
has in its driving point
for : impedance ?
R = 5Ω
(A) linear circuits 1 2+
(B) non-linear circuits V1(s) L = 2(s) V2(s)
(C) both linear and non-linear 1 2–
circuits (A) Zero
(B) One at origin
(D) circuits containing current
(C) One at infinity
circuits
(D) One on jω axis
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9. How is z 22 related to
11. In a bridge rectifier the secondary
h-parameters ?
voltage is 100 V, what should be the
(A) z22 = h22
minimum PIV for each diode ?
1
(B) z22 = h
22
(A) 100 V
h21
(C) z22 = h
22
(B) 141.4 V
h21
(D) z22 = − h
22 (C) 200 V
10. The pole-zero pattern of a filter is
(D) 282.8 V
shown in figure. The filter is :
12. An amplifier has a voltage gain of
Jω
J2
AV = 40 and 10% of the output is
J1
fedback. The gain with feedback
σ
is :
–J1
J2 (A) 40
(B) 32
(A) low pass
(B) high pass (C) 16
(C) band pass
(D) 8
(D) all pass
3 [P.T.O.
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15. Slew rate of op-amp becomes
13. In a CE small signal amplifier, the
important :
resistor R E is bypassed by a
(A) at low frequency
capacitor CE. The input impedance
(B) at high frequency
of this configuration is :
(C) at low input voltage
(A) hfe
(D) at high input voltage
(B) R E 16. The main advantage of CMOS
is :
(C) hie + (1 + hfe)RE
(A) Low power, high device density
(D) (1 + hfe)RE
(B) High speed, high device density
14. When a large sine wave drives a
(C) Low power, low device density
Schmitt trigger, the output
(D) High speed, low device density
is a : 17. Y = ABC + ABC + 1, the output Y
will be :
(A) rectangular wave
(A) zero
(B) triangular wave
(B) AB
(C) rectified sine wave
(C) 1
(D) series of ramps (D) ABC
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18. A CMOS D latch is transparent, 20. An eightbit flash ADC is
implemented using :
when :
(A) 8 comparators
(A) EN = 0
(B) 16 comparators
(B) EN = 1
(C) 64 comparators
(C) EN = tristate (D) 256 comparators
(D) Independent of EN 21. The register used in variable port
addressing in 8086 is :
19. A 64 kB memory device will
(A) AX
have :
(B) BX
(A) 16 address lines and 8 data
(C) CX
lines
(D) DX
(B) 20 address lines and 4 data
22. Address within a segment of 8086
lines is called :
(C) 64 address lines and 8 data (A) effective address
lines (B) physical address
(C) segment address
(D) 16 address lines and 16 data
(D) base address
lines
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23. Which of the following I/O device 25. Preferred protocol for long distance
communication is :
provides memory and I/O compatible
(A) parallel
signal ?
(B) serial
(A) 8255
(C) error handling
(B) 8279 (D) digital
(C) 8253 26. ‘‘My salary was increased by 15% !’’
Select the statement which will
(D) 8155
exactly reproduce the line of text
24. After power up in 8051 the above.
first location of the stack variable (A) printf(‘‘\’’ My salary was
increased by 15/% \!\ ‘‘\n’’);
is :
(B) printf(‘‘My salary was increased
(A) 07H
by 15% !\ n’’);
(B) 08H (C) printf(‘‘My salary was increased
by 15 ‘%’ !\n’’);
(C) 09H
(D) printf(‘‘\’’ My salary was
(D) 04H
increased by 15%% ! “\n’’);
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27. int X = 2 * 3 + 4 * 5;
29. Which of the following is the correct
What value will X contain in the
way of declaring a float pointer ?
sample code above ?
(A) 22 (A) float ptr;
(B) 26
(B) float * ptr;
(C) 46
(C) * float ptr;
(D) 70
(D) float ptr*;
28. Array passed as an argument to a
function is interpreted as : 30. Which one of the following will
(A) Address of the array read a character from keyboard
and will store it in the variable
(B) Value of the first element of the
C ?
array
(C) Address of the first element of (A) C=getc( );
the array (B) getc(&c);
(D) Number of elements of the (C) C=getchar(stdin);
array
(D) C=getchar( );
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31. An electromagnetic wave in a 33. The characteristic impedance of a
medium with permittivity ∈ and transmission line is 100 Ω, which is
permeability µ travels with a terminated into a load of 900 Ω.
λ
A transformer is to be added for
speed : 4
matching the impedance. Its
(A) ∈µ
characteristic impedance should
1
(B) ∈µ be :
∈ (A) 500 Ω
(C)
µ
(B) 700 Ω
µ
(D)
∈ (C) 900 Ω
32. Poynting vector represents :
(D) 300 Ω
(A) direction of propagation of EM
34. Increase in number of directors in
waves
Yagi antenna :
(B) direction of displacement
(A) increases the bandwidth
current
(B) decreases the bandwidth
(C) polarization vector
(C) decreases the gain
(D) equipotential surface
(D) increases null points
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35. When a plane polarized wave is 37. If 10 speech channels are
multiplexed in a TDM-PCM
incident on a conducting surface, the
telephone system and the signals
magnetic field at the interface is :
are sampled at 8 kHz rate. Then
(A) zero separation time between two frames
will be :
(B) same as in the incident
(A) 12.5 µ sec.
wave
(B) 15.0 µ sec.
(C) double that of the incident
(C) 1.25 µ sec.
wave
(D) 125 µ sec.
1 (D) that of the incident
2 38. What makes optical fiber immune to
wave
EMI ?
36. The frequency bandwidth required
(A) They transmit signal as electric
is largest for : current rather than light
(A) amplitude modulation (B) It has plastic cover on it
(C) Because it uses glass or polymer
(B) frequency modulation
as propagation medium
(C) digital modulation
(D) They transmit signal as light
(D) FSK modulation rather than electric current
9 [P.T.O.
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39. Microwave link repeaters are
41. In the reverse direction the
typically 50 km apart :
characteristics of a thyristor
(A) because of atmospheric
resembles to characteristics of a :
attenuation
(B) because of earth’s curvature (A) transistor switch
(C) because of output power (B) p-n rectifier
limitation of transmitter
(C) negative resistance
(D) to ensure that the applied d.c.
voltage is not excessive (D) two transistor model
40. Figure of merit of digital 42. For a UJT R B1 = 6 kΩ, R B2 = 3 kΩ
communication system is primarily
the intrinsic stand-off ratio will
determined by :
be :
(A) SNR and probability Pe
(A) 0.55
(B) Bandwidth and signalling rate
rs (B) 0.33
(C) Error probability and signalling
(C) 0.66
rate
(D) 0.44
(D) SNR and bandwidth
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45. Total internal reflection occurs when
43. Stimulated emission is observed in
light travels from :
the case of a :
(A) denser to lighter medium
(A) Discharge tube
(B) lighter to denser with incident
angle > critical angle
(B) LED
(C) denser to lighter with incident
(C) Laser
angle < critical angle
(D) Sun (D) lighter to denser medium
46. Which of the following forms of
44. An illuminated solar cell operates on
temperature sensor produces a large
I-V plot with voltage along X-axis
change in its resistance with
in the : temperature but is very non-
linear ?
(A) 1st
(A) a thermistor
(B) 2nd (B) platinum resistance thermo-
meter
(C) 3rd
(C) p-n junction sensor
(D) 4th quadrant
(D) pyroelectric sensor
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47. How many significant figures are 49. A system is said to be stable if and
only if :
present in the number 10,450 ?
(A) all poles lie on the right half of
(A) three
s-plane
(B) four (B) all poles lie in the left half of
s-plane
(C) five
(C) all poles and zero lie on the right
(D) ten
half of s-plane
48. Which of the following equipments (D) some poles lie on the right half
is used to study the topography of of s-plane and some lie on the
left half of s-plane
the sample ?
50. The problem with PI controller is,
(A) X-ray Diffractometer
its response to transients is :
(B) Spectrophotometer (A) very fast
(B) having a dead zone
(C) Spectrum Analyser
(C) non-linear
(D) Scanning Electron Microscope
(D) Sluggish
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ROUGH WORK
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ROUGH WORK
14Official key not published for this paper.
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Source: Savitribai Phule Pune University. Question paper published by Savitribai Phule Pune University.