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MH SET 2013: 17 February, Paper III, Electronic Science

  • Date: 17 February 2013
  • Paper code: 17FEB_Electronic_Science_PIII
  • Language: Bilingual
  • 23 pages
MH SET 2013 question paper, 17 February 2013, Paper III, Electronic Science, page 1 of 23
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FEB - 38313/III
                           Electronic Science
                                     Paper III
Time Allowed : 2½ Hours]                           [Maximum Marks : 150
Note : This Paper contains Seventy five (75) multiple choice questions. Each
       question carries Two (2) marks. Attempt All questions.


1.   JFET is a :
                                              4.    Match the following and choose the
     (A) Current controlled device with
                                                    correct option from the codes given
         high I/P resistance
                                                    below :
     (B) Voltage controlled device with
         high I/P resistance                        Set I                        Set II
     (C) Current controlled current
                                              (a)   FET                (i)    Same crystal
         source (CCCS)
     (D) Voltage controlled voltage                                           structure as that
         source (VCVS)
                                                                              of the substrate
2.   An ideal voltage source should
     have :                                   (b)   Epitaxy            (ii)   VVR

     (A) Zero internal resistance
                                              (c)   Schmitt trigger    (iii) Interconnection
     (B) Infinite internal resistance
                                              (d)   Metallization      (iv)   Hysteresis
     (C) A small internal resistance
     (D) Large internal resistance                  Codes :
3.   When by-pass capacitor across the                        (a)     (b)        (c)       (d)
     emitter lead in CE-amplifier is
     disconnected, it causes :                       (A)      (ii)     (i)       (iv)      (iii)
     (A) Current gain to increase
                                                     (B)       (i)    (iii)      (ii)      (iv)
     (B) Voltage gain to increase
                                                     (C)      (iii)   (iv)       (i)       (ii)
     (C) Current gain to decrease
     (D) Voltage gain to decrease                    (D)      (iv)    (ii)       (iii)      (i)

                                          1                                               [P.T.O.
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FEB - 38313/III

5.   Astable     multivibrator    is   a       8.       The identical resistors are connected
     multivibrator with duty cycle equal
     to :                                               in the following topology, where

     (A) 50%                                            value of each resistor is 1 Ω. The

     (B) 100%                                           effective equivalent resistance
     (C) 30%
                                                        measured between Node B and Node
     (D) 33%
                                                        H is .....................
6.   Negative feedback in CE-amplifier
     is to :
                                                    A                 1Ω
     (A) Increase the voltage gain                                                        B
                                                                1Ω                             1Ω
     (B) Increase the current gain                                              1Ω
                                               1Ω                       D                 1Ω
     (C) Increase the power-band width                                                              C

     (D) Decrease power band width
                                                           1Ω
                                                                                      F
                                                    E                                               1Ω
7.   Important characteristics of an
                                                                                              1Ω
     emitter follower are :                              1Ω               1Ω
                                                                                     1Ω
     (A) High I/P impedance and high                                H                               G
            O/P impedance

     (B) High I/P impedance and low
            O/P impedance                               (A) 2/3 Ω

     (C) Low I/P impedance and low                      (B) 5/6 Ω
            O/P impedance
                                                        (C) 1/6 Ω
     (D) Low I/P impedance and high
                                                        (D) 1/3 Ω
            O/P impedance

                                           2
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FEB - 38313/III

                                                    10. A series RLC circuit has a current
9.      The circuit shown in the figure has             which lags the applied voltage by
                                                        30°. The inductor voltage maximum
        initial current iL(0 –) = 1A through            is twice the capacitor voltage
                                                        maximum, and
        the inductor and an initial voltage
                                                              VL = 10.0 sin 1000 t.

        Vc(0–) = – 1V across the capacitor.               Given that : R = 20 Ω, L and C are
                                                          respectively :
        For input V(t) = u(t), the Laplace                (A) L = 2.31 mH, C = 86.5 µF
                                                          (B) L = 23.1 mH, C = 86.5 µF
        transform of the current i(t) for
                                                          (C) L = 23.1 mH, C = 8.65 µF
        t > 0 is :                                        (D) L = 23.1 µH, C = 86.5 nF
                                                    11. Match List I and with List II and
                   1Ω      1H                           select the correct answer from the
                                                        codes given below :

                   i(t)                                     List I                    List II
                                      +
 V(t)                                      1F       (a)   Incidence matrix      (1)   Links
                                       –
                                                    (b)   Cutset matrix         (2)   Twigs

                                                    (c)   Tie set matrix        (3)   Nodes

                                                    (d)   Reduced incidence     (4)   Branch
                   s+2                                    matrix
        (A)    2
              s +s+1
                                                          Codes :

                   s−2                                    (A) (a)—(3), (b)—(1), (c)—(2),
        (B)                                                   (d)—(4)
              s2 + s + 1
                                                          (B) (a)—(3), (b)—(2), (c)—(1),
                   s−2                                        (d)—(3)
        (C)    2
              s + 2s + 1                                  (C) (a)—(1), (b)—(2), (c)—(3),
                                                              (d)—(4)
                    s
        (D)                                               (D) (a)—(2), (b)—(1), (c)—(3),
              s2 + s + 1
                                                              (d)—(4)

                                                3                                        [P.T.O.
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FEB - 38313/III

12. The Y-parameters of the two-port              13. The driving point impedance Z(s) of

                                                      a network has the pole-zero locations
      network shown in the following
                                                      as shown in the figure. If z(0) = 3,
      figure are Y 11 = Y 22 = 6 mho,
                                                      then z(s) is :
      Y12 = Y21 = 4 mho. The driving

                                                                           Im
      point admittance at port 2-2', if the
                                                                                s-plane
      source voltage is 100 V with an                       X              1


      impedance of 1 Ω is :
                                                     . .
                                                     –3          –1
                                                                                            Re


                 1I                                                              O-denotes zero
                 •   1
                                         •2                 X              1     X-denotes pole
            1Ω                      I2   +
  +               +
Vs                                       V2
  –              V1
                  –                      –
                 •                       •2
                 1

                                                                3(s + 3)
            1                                         (A)
      (A)       mho                                          2
          3.714                                             s + 2s + 3

                                                                2(s + 3)
      (B) 3.714 mho                                   (B)    2
                                                            s + 2s + 2

                                                                3(s − 3)
      (C) 0.3714 mho                                  (C)
                                                            s2 − 2 s − 2

               1                                                2(s − 3)
      (D)          mho                                (D)    2
            0.3714                                          s − 2s − 3


                                              4
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                                                           15. Match the following. Figures show
            14. For the circuit shown in figure, the           the conduction region for different
                                                               amplifiers for the input and choose
                                                               the correct answer from the codes
                                                               given below :
                 Thevenin’s equivalent impedance


                                                           (p)                            (1)   Class B
                 between the output terminals



                 is :
                                                           (q)                            (2)   Class C




                           –j4 Ω    j5 Ω   –j4 Ω
                                                           (r)                            (3)   Class AB
                                                   A
                         3Ω                                (s)                            (4)   Class A
                     ~             4Ω
             ° ∠0°
        11.350
4.83∠0−°1.13
48.3                                                             Codes :
                                   j6 Ω
                                                                   (A) (p)—(4), (q)—(2), (r)—(3), (s)—(1)
                                                   B
                                                                   (B) (p)—(1), (q)—(2), (r)—(4), (s)—(3)

                                                                   (C) (p)—(4), (q)—(3), (r)—(1), (s)—(2)
                 (A)
                                                                   (D) (p)—(4), (q)—(1), (r)—(2), (s)—(3)

                                                           16. Product of gain and bandwidth is
                 (B)
                                                                   constant when the roll-off is :

                 (C)                                               (A) – 10 dB/decade

                                                                   (B) – 20 dB/decade

                 (D)                                               (C) – 30 dB/decade

                                                                   (D) + 10 dB/decade
                                                       5                                           [P.T.O.
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FEB - 38313/III

17. In a two-stage amplifier one stage        19. A Gyrator is a circuit using OP
                                                  Amps, that simulates :
    has a lower critical frequency of
                                                  (A) Inductance property with the
    850 Hz and an upper critical
                                                         help of resistors and capacitors
    frequency of 100 kHz. The other has
                                                  (B) Resistance property with the
    correspondingly 1 kHz and 230 kHz                    help    of    inductance   and

    critical frequencies. The overall                    capacitors

                                                  (C) Capacitance property with the
    bandwidth is :
                                                         help    of    resistance   and
    (A) 99 kHz                                           inductances

    (B) 229.15 kHz                                (D) The circuit does not use any of
                                                         the components
    (C) 99.15 kHz
                                              20. The electrothermal filters are used

    (D) 229 kHz                                   in the :

                                                  (A) less than 1 Hz to audio
18. A varactor diode exhibits :
                                                         range
    (A) A variable capacitance that               (B) 50 Hz to 100 kHz range

        depends on reverse voltage                (C) 100 kHz to 1 MHz range

    (B) A variable resistance that                (D) 90 MHz to 100 MHz range

                                              21. The      principle    of   MODEMs
        depends on reverse voltage
                                                  is :
    (C) A variable capacitance that
                                                  (A) FSK
        depends on forward current
                                                  (B) PWM
    (D) A constant capacitance over a             (C) Phase adder
        range of reverse voltages                 (D) Automatic fine tuning
                                          6
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22. What is the meaning of RAM and             24. Consider the following series of
                                                   TTL :
     what is its primary role ?
                                                     (i)     74
     (A) Readily available memory, it is
                                                     (ii) 74H
          memory that can be reached by              (iii) 74L
          any sub-item within a computer             (iv) 74S
          and at any time                            Write them in increasing order of
                                                     power dissipation per gate :
     (B) Random access memory, it is
                                                       (A)        (iii)    (i)            (iv)       (ii)
          memory used for short term
                                                       (B)          (i)   (ii)            (iii)      (iv)
          temporary data storage within
                                                       (C)        (iv)     (i)            (ii)       (iii)
          the computer
                                                       (D)        (ii)    (iii)           (iv)       (i)
     (C) Random access memory, it is           25. Match List I with List II and select
          the first level of memory used           the answer using the codes given
                                                   below :
          by the computer in all of its
                                                           List I                            List II
          operations
                                               (a)   Schmitt trigger             (i)     Toggle switch
     (D) Resettable automatic memory,          (b)   J-K flip-flop               (ii)    Delay switch
          it is the memory that can be         (c)   D flip-flop                 (iii)   Race around
          used and then automatically                                                    condition
          reset, or cleared, after being       (d)   T flip-flop                 (iv)    Comparator and

          read from or written to                                                        square wave
                                                                                         generator
23. A BCD counter is a .................
                                                       Codes :
     (A) Binary counter                                           (a)     (b)             (c)        (d)

     (B) Full-modulus counter                          (A)        (iv)    (iii)           (ii)       (i)
                                                       (B)          (i)   (ii)            (iii)      (iv)
     (C) Decade counter
                                                       (C)        (ii)     (i)            (iv)       (iii)
     (D) Johnson counter                               (D)        (iii)    (i)            (iv)       (ii)

                                           7                                                      [P.T.O.
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26. A certain system contains two              Direction : Read the following paragraph

   identical circuits operating in
                                                   and answer the Question Nos. 27 and
   parallel. As long as both are
                                                   28 based on the same.
   operating properly, the outputs of

   both circuits are always the same.              ‘‘Many DACs use a BCD input code

   A failure in one of the circuits
                                                   where 4-bit code groups are used for
   produce differing outputs. One of the
                                                   each decimal digit. In one such
   following logic circuits is the
                                                   12-bit BCD digital to analog
   best alternative to detect the

   fault :                                         converter the full scale output


         Circuit A                                 is 9.99 V.’’
   (A)                     Failure
         Circuit B
                                               27. The percent resolution of above

         Circuit A
                                                   referred DAC will be :
   (B)                      Failure
         Circuit B
                                                   (A) 0.001%
         Circuit A

   (C)                      Failure
                                                   (B) 0.01%
         Circuit B


         Circuit A                                 (C) 0.1%
   (D)                       Failure
         Circuit B
                                                   (D) 1.0%


                                           8
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28. The step size of the above referred
                                                         Direction : Read the following paragraph
      DAC is :
                                                             regarding the 8085 assembly
      (A) 0.001 V
                                                             language program :
      (B) 0.01 V
                                                             ‘‘The main program is stored at
      (C) 0.1 V
                                                             (0100) H. The main program has
      (D) 1.0 V
                                                             called the subroutine at (0150)H,
29. Match List I (Logic family) with
                                                             when the microprocessor is executing
      List II (Typical fanout) and select
                                                             the    instruction    at   location
      the answer using the codes given
      below :                                                (0151)H. The program listing is as

      List I                       List II                   follows.’’

(a)   RTL                  (i)     > 50                      0100         LXI SP, 0400H

(b)   TTL                  (ii)    5                         0103         EI

(c)   ECL                  (iii)   10
                                                             0120         CALL 0150 H
(d)   CMOS                 (iv)    25
                                                             0130         HLT
        Codes :
                                                             0150         PUSH B
                (a)    (b)          (c)      (d)
                                                             0151         LXI B, 10 FFH
        (A)     (ii)   (iv)         (iii)     (i)

        (B)     (ii)   (iii)        (iv)      (i)            0154         MOV C, A

        (C)     (i)    (iv)         (ii)     (iii)           015E         POP B

        (D)    (iii)   (iv)            (i)   (ii)            015F         RET

                                                     9                                    [P.T.O.
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Direction : Answer the Question Nos.             33. In interfacing 16 keys and 8 relays
    30, 31 and 32 based on the above                 directly using 8255 IC with 8085
    Scenario.                                        microprocessor     the   minimum
30. Assuming that before CALL 0150 H,                number of pins of 8255 required
    the stack was not used, specify the              are :
    content of top two locations of the              (A) 4 inputs, 4 outputs, 8 outputs
    stack :
                                                     (B) 4 inputs, 8 outputs, 8 I/Os
    (A) 23H, 01H
                                                     (C) 8 I/O only
    (B) 23H, 00H
                                                     (D) 12 I/O only
    (C) FFH, 00H
                                                 34. By using 8279 IC with 8085
    (D) 00H, FFH                                     the following functions can be
31. Specify the stack locations where the            done :
    contents of register pair B are                  (A) Relay interfacing
    stored :
                                                     (B) stepper motor interfacing
    (A) 03FDH and 03FCH
                                                     (C) Display interfacing only (LCD/
    (B) 03FDH and 03FEH                                  LED)
    (C) 03FEH and 03FFH                              (D) Display (7 segment) interfacing
    (D) 03FBH and 03FCH                                  and keyboard interfacing

32. When the program was interrupted,            35. Timer ports of 8051 microcontroller
                                                     can be used for :
    what is the memory address stored
    on the stack ?                                   (A) Generation of waveforms
                                                     (B) Generation of PWM
    (A) FFFFH
                                                     (C) Measurement of time (ON, OFF
    (B) 015FH                                            and Freq.) of input signal with
    (C) 0154H                                            gate control
                                                     (D) As a counter and (B) and (C)
    (D) 0150H
                                                         above

                                            10
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36. Match the following and choose the
                                                      38. After execution of the following
    correct answer from the codes given
    below :                                               statement :

Ports of 8051                     Application             X = (int *) Malloc(100);
(i)     Port 0        (a)   I/O + control
                                                          (assume size of int as 2 bytes)
(ii)    Port 1        (b)   I/O + higher order
                                                          The following amount of memory for
                            address bus
                                                          execution will be allotted :
(iii)   Port 2        (c)   Low address & data
                            bus                           (A) 2 bytes
(iv)    Port 3        (d)   I/O port only
                                                          (B) 100 bytes
                      (e)   Timer port + Input
                            only                          (C) 200 bytes

        Codes :                                           (D) 4 bytes
        (A) (i)—(c), (ii)—(d), (iii)—(b),
                                                      39. The output of the following
            (iv)—(a)
                                                          program :
        (B) (i)—(d), (ii)—(b), (iii)—(a),
            (iv)—(e)                                          void main (void)
        (C) (i)—(e), (ii)—(a), (iii)—(b),
                                                          {
            (iv)—(c)
        (D) (i)—(a), (ii)—(b), (iii)—(c),                     unsigned char flag=0X00;
            (iv)—(d)
                                                              flag!=(1<< 7)
37. The structure variables can be
    passed to the function as a :                             printf("%d", flag);

        (A) Copy of the structure variable                (A) 0X00
        (B) Pointer to a structure variable
                                                          (B) 0X70
        (C) Both (A) and (B) depending on
            speed of operations required                  (C) 0X80

        (D) Both (A) and (B)                              (D) 0XFF

                                                 11                                      [P.T.O.
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40. Consider the following statement               42. What will be the output of the
    fprintf(outfile, "programming in C is              following program ?
    fun.\n");
                                                       #include <stdio.h>
    The ‘‘out file’’ in this statement is :
                                                       int abc(int u, int v)
    (A) name of a variable to be
        printed                                        {

    (B) file pointer previously declared                      int tmp;
        and defined by fopen
                                                           while (v !=0) {
    (C) identifier representing the file
                                                              tmp=u%v;
        name
    (D) pointer of the variable to be                         u=v;
        printed                                               v=tmp
41. (A) Assertion : Various objects can                       }
    be drawn on the computer screen
    with proper scale factors and colour                   return u;
    selection                                          }
    because :
                                                       int main(void)
    (R) Reason : Matching band rate
                                                       {
    is a must for connecting a mouse to
    serial port.                                              int result;
    (A) Both (A) and (R) are true                             result=abc(150, 35);
        statements and the reason is a
        correct explanation of assertion                      printf("result=%d", result);

    (B) Both (A) and (R) are true                      return 0;
        statements but the reason is not               }
        a correct explanation of
        assertion                                      (A) 35

    (C) The (A) is true but (R) is                     (B) 4
        false                                          (C) 10
    (D) The (A) is false but (R) is
                                                       (D) 5
        true

                                              12
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43. A uniformly charged sphere is                 Directions : Given the transmission line
                                                      below, obtain the following
    compressed slightly on opposite                   quantities, for Question Nos. 45, 46
    sides. It will exhibit a :                        and 47.


    (A) Monopole
                                                                50 Ω

    (B) Monpole + dipole
                                                   Vg      S              Z0 = 50 Ω      ZL 75 Ω

    (C) quadrupole
                                                   30 V
                                                   (rms)
    (D) monopole + qaudrupole
                                                                       2.25 λ

44. Given that the time variation of
                                                  45. The input impedance is :
    electric and magnetic fields is e jωt,              (A) 66.66 Ω
    match the following and choose the                  (B) 33.33 Ω
    correct option given below : :                      (C) 50 Ω
          →   →                                         (D) 75 Ω
    (p)   ∇×E         (1)   0
                                                  46. The         reflection          coefficient
          →   →                   →
    (q)   ∇×H         (2)   – jωµ H                   is :
          →   →                                         (A) 1
    (r)   ∇.D         (3)   Pν
                                                        (B) 0
          →   →                       →
    (s)   ∇.B         (4)   (σ + jω ∈) E                (C) 0.2

    Options are :                                       (D) 0.5
                                                  47. Instantaneous power delivered to
    (A) (p)—(3), (q)—(1), (r)—(2), (s)—(4)            the load :

    (B) (p)—(4), (q)—(2), (r)—(1), (s)—(3)              (A) 17.28 W
                                                        (B) 16 W
    (C) (p)—(4), (q)—(3), (r)—(1), (s)—(2)
                                                        (C) 18.39 W
    (D) (p)—(2), (q)—(4), (r)—(3), (s)—(1)              (D) 36 W

                                             13                                           [P.T.O.
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                                                  49. An incident wave has amplitude 1V.
48. A circulator with direction of flow of
                                                                                    1
      power is shown in the figure.                   Corresponding reflected one is V .
                                                                                    3
                                                      The VSWR is :
                    4                                 (A) 3
                                                      (B) 2
                                                      (C) 1
                                                           1
                                   3
                                                      (D)
      1                                                    2
                                                      The tuned circuit of the oscillator in
                                                      a simple AM transmitter uses a
                                                      40 µH coil and 12 nF capacitor. If
                                                      the oscillator output is modulated by
                    2
                                                      audio frequency of 5 kHz. Answer
                                                      questions 50 and 51 based on the
      Corresponding S matrix is :                     above information.
                                                  50. Calculate the lower side band
                        0   0 0 1                   frequency :
                                                    (A) 224 kHz
(A)                 (B)          
                        1   0 0 0
                                                      (B) 228 kHz
                                 
                        0   1 0 0                   (C) 442 kHz
                                 
                                                    (D) 19 kHz
                        0   0 1 0
                                                  51. The bandwidth needed to transmit
                        0   1 0 0                   this amplitude modulated wave
    1    0 0 0
                                                  is :
                               
(C) 0    1 0 0 (D)    1   0 0 0
                                                      (A) 5 kHz
                               
    0    0 1 0        0   0 1 0                   (B) 2 kHz
                               
                                                  (C) 10 kHz
    0    0 0 1        0   0 0 1
                                                      (D) 7 kHz
                                             14
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52. Match the following and choose the                53. When input signal strength = 0.5 W,
                                                          maximum frequency deviation =
      correct answer from the codes given                 60 kHz, base band signal cutoff
                                                          frequency = 15 kHz, received white
      below :
                                                          Gaussian noise power spectral
                                                          density = 10 –9 W/Hz and the
       Column I                 Column II
                                                          average power of modulating signal
                                                          = 0.1 W, the SNR of an FM
(a)   Amplitude         (i)     Frequency
                                                          limiter-discriminator demodulator
      Modulator                 Discriminator
                                                          is ...........
                                                          (A) 36.08 dB
(b)   DSBSC modulator   (ii)    Ring modulator
                                                          (B) 26.07 dB
(c)   SSB modulator     (iii)   Switching                 (C) 46.07 dB
                                                          (D) 30 dB
                                 modulator
                                                      54. (A) Assertion : Use of a compressor
(d)   VSB modulator     (iv)    Phase                     improves the signal to quantization
                                                          noise ratio of a PCM system
                                discrimination            because :
                                                          (R) Reason : The compressor
                                method                    provides lower gain to weak signals
                                                          and higher gain to the strong
      Codes :                                             signals.

      (A) (A)—(3), (B)—(2) ,        (C)—(1) ,             (A) Both (A) and (R) are true
                                                              statements and the reason is
          (D)—(4)                                             correct explanation of the
                                                              assertion
      (B) (A)—(2), (B)—(3) ,        (C)—(4) ,
                                                          (B) Both (A) and (R) are true
          (D)—(1)                                             statements and the reason is not
                                                              correct explanation of the
      (C) (A)—(3), (B)—(1) ,        (C)—(2) ,                 assertion
          (D)—(4)                                         (C) The (A) is true but (R) is
                                                              false
      (D) (A)—(2), (B)—(4) ,        (C)—(3) ,             (D) The (A) is false but (R) is
          (D)—(1)                                             true

                                                 15                                    [P.T.O.
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55.


                 A3   A2   A1

      Source A
                                           Frame 3          Frame 2         Frame 1
                                          A3 B3 C3         A2 B2   C2     A1 B1 C1
                 B3   B2   B1

  Source B                        Mux


                 C3   C2   C1                            Common medium

  Source C




       The above diagram                       57. The correct relationship from among
       represents a :                              the following is :
       (A) FDM system                               (A) BW (ASK) > BW (FSK)

       (B) TDM system                               (B) BW (BPSK) > BW (QPSK)
                                                    (C) Noise immunity of QPSK <
       (C) WDM system
                                                        Noise immunity of BFSK
       (D) PCM system                               (D) Noise immunity of ASK > =
56. For a polar NRZ signal representing                 Noise immunity of PSK
    1 by a positive pulse X1 and 0 by          58. A thyristor of thermal resistance
    a negative pulse X2 of duration T,             1.8°C/W is mounted on a neat sink
    the impulse response of a matched              of thermal resistance 2.0°C/W. What
                                                   is the maximum power loss of thyristor
    filter is given by :
                                                   if the junction temperature is not to
       (A) h(t) = X1(T – t) + X2(T – t)            exceed 125°C in an ambient of 40°C.
       (B) h(t) = X1(t) + X2(t)                     (A) 5.2 W

       (C) h(t) = X1(T – t) – X2(T – t)             (B) 11.4 W
                                                    (C) 18.6 W
       (D) h(t) = X1(t) – X2(t)
                                                    (D) 22.4 W

                                          16
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59. You need a very efficient device to             62. Match List I with List II and choose
    control the speed of AC fan motor.
                                                        the correct answer from the codes
    An appropriate device for the same
    would be :                                          given below :
      (A) SCR         (B)      Triac                          List I                           List II

      (C) UJT         (D)      PUT                  (a)   Single mode fiber           (i)    Local area
                                                                                             network
60. The following is the circuitary for a
    dimmer :                                        (b)   Step index                  (ii)   Low cost
                                                          multimode fiber                    application
          Lamp
                                                    (c)   Graded index fiber          (iii) Low bandwidth
                      R1
      AC supply                                     (d)   PCS fibers                  (iv) High bandwidth
  ~                   R2    Diac
                                                            Codes :
                                       Triac
                                                                 (a)          (b)             (c)        (d)
                  C
                                                          (A) (iv)     (i)      (iii)   (ii)
                                                          (B) (ii)     (i)      (iv)   (iii)
      What method of power control is                     (C) (iv)    (iii)      (i)    (ii)
      used ?                                              (D)   (i)   (iii)     (iv)    (ii)
      (A) Phase control                             63. Match List I with List II and choose
      (B) Feedback control                              the correct answer from the codes
      (C) Proportional control                          given below :
      (D) Burst firing                                        List I                           List II

61. Assertion (A) : Optical communi-                (a)   Fusion splicing             (i)    Low cost
    cation is called information super              (b)   3 pin splicing              (ii)   Multimode
    highway.
                                                    (c)   Plastic ‘V’ grove           (iii) Low insertion
      Reason (R) : Optical pulses travel
                                                          splicing                           loss
      at higher speed as compared to
      copper cable.                                 (d)   Square tube                 (iv) Graded index

      (A) Both (A) and (R) are true, and                  splicing                           fibers
          (R) is the correct explanation                    Codes :
          of (A)
                                                                      (a)      (b)            (c)       (d)
      (B) Both (A) and (R) are true, but
                                                            (A)      (iii)    (iv)            (i)       (ii)
          (R) is not correct explanation
          of (A)                                            (B)       (ii)     (i)           (iv)      (iii)
      (C) (A) is true, but (R) is false                     (C)       (i)     (iii)           (ii)     (iv)
      (D) (A) is false, but (R) is true                     (D)      (iv)     (ii)           (iii)      (i)

                                               17                                                     [P.T.O.
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64. The following display device is not           66. The most common type of vibration
    suitable for high frame rate
                                                      sensors are :
    display :
                                                      (A) Piezoelectric
    (A) CRT

    (B) LCD                                           (B) Capacitive

    (C) LED                                           (C) Resistive

    (D) PDP
                                                      (D) (A) and (B) both
65. Consider the following light sources.
                                                  67. The magnetic flow meter has the
    Give their suitability in the order of

    merit for optical communication in                following disadvantages :

    fibers :
                                                      (A) Suitable for high and low
    (a) LED
                                                          velocities
    (b) Ruby laser
                                                      (B) Suitable     for     conductivity
    (c) Febry Perrot laser diode
                                                          greater than 20 mho/cm
    (d) DFB laser

                                                      (C) Gives slow response to flow
    (A) (b), (a), (c), (d)

    (B) (a), (c), (b), (d)                                changes


    (C) (c), (a), (d), (b)                            (D) Very low cost and require

    (D) (d), (a), (b), (c)                                minimum maintenance

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68. Match the following and choose the                         69. Match the following and choose the
    correct answer from the codes given                            correct answer from the codes given
    below :                                                        below :
         Transducer           Principle                          Measurement                     Measuring

(i)     Photovoltaic    (a)       An emf is generated                  Quantity                  Unit/Symbol
                                  across the junction
                                                               (i)      Phase angle        (a)     Pa or N/m2
                                  of two dissimilar
                                                               (ii)     Angular velocity   (b)     kg/m
                                  metals when two
                                                               (iii)    Linear denstiy     (c)     rad/s
                                  ends are at different
                                  temperatures                 (iv)     Stress             (d)     Radian

(ii)    Moving coil     (b) Motion of a coil in                                            (e)     kg/m3
        generator             a     magnetic      field                 Codes :
                              generates a voltage                       (A) (i)—(d), (ii)—(b) ,      (iii)—(a) ,
(iii)   Piezoelectric   (c) An emf is generated                             (iv)—(c)
        pickup                due to external force                     (B) (i)—(e), (ii)—(a) ,      (iii)—(c) ,
                              on quartz                                     (iv)—(b)
(iv)    Thermocouple    (d) A voltage is generated
                                                                        (C) (i)—(a), (ii)—(b) ,      (iii)—(c) ,
                              in a semiconductor                            (iv)—(e)
                              junction device due
                                                                        (D) (i)—(d), (ii)—(c) ,      (iii)—(b) ,
                              to radiant energy                             (iv)—(a)
(v)     Thermistor
                                                               70. The resistors in a bridge are given
        Codes :                                                    by R1 = R 2 = R 3 = 120 Ω and
        (A) (i)—(d), (ii)—(b) ,            (iii)—(c) ,             R4 = 121 Ω. If supply voltage is
            (iv)—(a)                                               10.0 V dc, then the offset voltage
        (B) (i)—(a), (ii)—(d) ,            (iii)—(b) ,             will be :
            (iv)—(c)                                                    (A) + 20.7 mV
        (C) (i)—(b), (ii)—(c) ,           (iii)—(d) ,
                                                                        (B) – 20.7 mV
            (iv)—(a)
                                                                        (C) 0.0 mV
        (D) (i)—(c), (ii)—(a) ,            (iii)—(b) ,
            (iv)—(d)                                                    (D) 1.0 mV

                                                          19                                               [P.T.O.
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71. In a PID control system, the control
    equation will be :                                     73. The system described by dx = f ( x)
                                                                                       dt
       (A) Vout = KP * (DE) + PI * PD                          is :
       (B) Vout = KP * (DE) + PI + PD                          (A) an autonomous system
       (C) Vout = KP * [DE + PI + PD]
                                                               (B) a static system
       (D) Vout = [KP * (DE)/PI] * PD
                                                               (C) a time dependent system
72. Match the following and select the
    correct answer from the codes given                        (D) a non-linear system
    below :
                                                           74. The characteristic equation of a
(i)    Bode plot          (a) Stability of linear
                                                               system is given by :
                              control system
                                                               s6 + 3s5 + 8s4 + 18s3 + 37s2 + 75s
(ii)   Root locus plot    (b) Stability in
                                                               + 50 = 0
                              frequency response
(iii) Nyquist criterion   (c) Analysis of
                                                               The system is :

       & Nicholas chart       frequency response               (A) Stable
(iv) Hurwitz and          (d) Method to determine              (B) Unstable
       Routh criterion        the roots of a
                                                               (C) Marginally stable
                              characteristic

                              equation
                                                               (D) Conditionally stable

                          (e) Compensation and             75. The open loop transfer function of
                              control of close loop            a feedback system is :
                              system                                                  k(1 + s)
       Codes :                                                         G(s) H(s) =    (1 − s)
       (A) (i)—(d), (ii)—(b) ,         (iii)—(c) ,
                                                               The value of k for which the system
           (iv)—(a)
                                                               is stable, is :
       (B) (i)—(a), (ii)—(b) ,         (iii)—(c) ,
           (iv)—(d)                                            (A) k < 1

       (C) (i)—(a), (ii)—(b) ,         (iii)—(c) ,             (B) k > 1
           (iv)—(e)                                            (C) k = 1
       (D) (i)—(c), (ii)—(d) ,         (iii)—(b) ,
                                                               (D) k = 0
           (iv)—(a)
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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.