2012 December UGC NET Solved Question Paper in Electronic Science, Paper III

Answer: (B)


Answer: (A)


Answer: (A)


Answer: (D)


5. If the branch in any network has a current source then the analysis is carried out by _______ analysis method.

(A) Mesh

(B) Node

(C) Super mesh

(D) Super node

Answer: (C)


6. The transfer function of RC low-pass filter network

(A) RCs/1 + RCs

(B) 1/1 + RCs

(C) RC/1 + RCs

(D) S/1 + RCs

Answer: (B)


7. Biasing is done in class A mode to

(A) Save power

(B) Improve stability

(C) Reduce number of sources

(D) Both (B) and (C)

Answer: (D)


8. In analog computation, we use

(A) Both integrator and differentiator

(B) Only integrator

(C) Only differentiator

(D) Both in pair

Answer: (B)


Answer: (C)


10. For IOLmax = 16 mA and IILmax = 0.0016 A, the fan-out (low) is

(A) 16

(B) 10

(C) 1

(D) 1.6

Answer: (B)

Answer: (B)


12. The largest decimal number that can be stored in a MOD-64 counter is

(A) 64

(B) 15

(C) 16

(D) 63

Answer: (D)


13. What is the Register address which matches with the address of the stack?

(A) 03H

(B) 07H

(C) 013H

(D) 13H

Answer: (B)


14. In 8259, to avoid causing an interrupt due to an accidental noise pulse, the following action is done:

(A) All unused interrupt lines are shorted together.

(B) All unused interrupt lines are connected to Vcc.

(C) All unused interrupt lines are connected to ground.

(D) All unused interrupt lines kept open.

Answer: (C)


15. Which of the ports in 8255, in which part of the port pins can be used as input lines and part of the port pines can be used as output lines?

(A) PA

(B) PB

(C) PC

(D) PD

Answer: (C)


16. Which loop structure would execute its statements at least once even if the test condition fails for the first time itself?

(A) For

(B) if-else

(C) Do-while

(D) While

Answer: (C)


17. The expression evaluates to false in

int l = 3, J =7;

double f = 5.5, g = 4.5;

charch = ‘T’;

(A) (l < = 5) && (ch = = ‘T’)

(B) (l< 8) 11 (ch = = ‘L’)

(C) (f > = 6) 11 (l . j) < 15

(D) (f + g) = = 10.011 i < 2

Answer: (C)


18. Word NEHA is to be entered in an array. Which array declaration is proper?

(A) Char name [4] = {‘N’, ‘E’, ‘H’, ‘A’};

(B) Char name [5] = {‘N’, ‘E’, ‘H’, ‘A’ ‘\O’};

(C) Char name [4] = “NEHA”;

(D) Char name [4] = ‘NEHA’;

Answer: (B)


Answer: (C)


20. An air filled rectangular waveguide has dimensions 6 cm X 4 cm. The cut off frequency for TE10 is

(A) 2.5 GHz

(B) 25 MHz

(C) 20.5 GHz

(D) 5 GHz

Answer: (A)

21. An antenna, when radiating, has a highly directional radiation pattern. When the antenna is receiving, its radiation pattern

(A) Is more directive

(B) is less directive

(C) is same that of transmitting antenna

(D) Exhibits no directivity at all.

Answer: (C)


22. The modulation index of an AM wave in changed from 0 to 1. The transmitted power is

(A) Unchanged

(B) Halved

(C) Doubled

(D) Increased by 50 percent

Answer: (B)


23. In a low level AM system, amplifiers following the modulated stage must be

(A) Linear devices

(B) Harmonic devices

(C) Class C amplifier

(D) Non-linear devices

Answer: (B)


24. Indicate the false statement. The square of the thermal noise voltage generated by a resistor is proportional to

(A) Its temperature

(B) Its resistance

(C) Boltzmann constant

(D) The bandwidth over which it is measured

Answer: (A)


25. The output of a dc motor depends mainly on

(A) Speed and torque

(B) Speed and back emf

(C) Speed and applied voltage

(D) Speed and load resistance

Answer: (A)


26. Which one of the following is an adjustable IC voltage regulator?

(A) IC 7824

(B) IC 7912

(C) LM 338

(D) IC 7808

Answer: (C)


27. The attenuation of single mode fibers is 0.2 dB/km, at a transmission length of 100 kms. The output signal strength is reduced to

(A) 10% of transmitted power

(B) 1% of transmitter power

(C) 5% of the transmitted power

(D) 20% of the transmitted power

Answer: (B)


Answer: (C)


Answer: (C)


30. A system is said to be stable if and only if

(A) All poles lie on the right half of S. plane.

(B) All poles lie in the left half of the S-plane.

(C) All poles and zeros lie on the right half of S-planes.

(D) Some poles lie on the half of the S-plane and some lie on the right half of the S-plane.

Answer: (B)


31. Which of the following is/are valid statement(s)?

I. AJFET has one built-in diode.

II. AJFET has two built-in diode.

III. The pinch off voltage of a JFET has same magnitude as that of gate voltage.

IV. A JFET is a voltage controlled device.

(A) I, III, IV



(D) II, IV

Answer: (B)


Answer: (B)


Answer: (A)


34. Which of the following circuit come under the class of combinational logic circuits?

I. Full Adder

II. Full Subtractor

III. Counter

IV. Multiplexer

(A) I and II are correct.

(B) I, II, IV are correct.

(C) II, III, IV are correct.

(D) I, III and IV are correct.

Answer: (B)


35. For using 8253 in counter mode from a initial value.

I. The control world for selection of counter is done.

II. The initial value will be kept in the counter before the selection of counter.

III. Selection of BCD mode is done.

IV. The initial value will be loaded to counter after the selection of counter.

(A) I, III and IV are to be fulfilled.

(B) I, II and III are to be fulfilled.

(C) II, III and IV are to be fulfilled.

(D) II, I and IV are to be fulfilled.

Answer: (A)


36. Which of the following statements will post increment the variable by 1?

I. a = a + 1;

II. a + = 1;

III. a + +;

IV. a = + 1;

(A) Options I, II, III are correct.

(B) Options II, III, IV are correct.

(C) Options I, II are correct.www.netugc.com

(D) Options III, IV are correct.

Answer: (A)


37. In optical fiber communications

I. Inter modal dispersion can be avoided by using SMF.

II. Inter modal dispersion can be avoided by using MMF.

III. Third transmission window wavelength is used to avoid Rayleigh scattering losses.

IV. 800-900 nm window is used to avoid Rayleigh’s scattering losses.

(A) Options II and III are correct.

(B) Options II and IV are correct.

(C) Options I and III are correct.

(D) Options IV and I are correct.

Answer: (C)


38. Indicate the false statement.

(i) HF mixers are generally noiser than HF amplifier.

(ii) Impulse noise voltage is independent of bandwidth.

(iii) In thermal noise, the noise power generated by a resistor is proportional to the bandwidth.

(iv) Industrial noise is not an impulse type.

(A) (i) and (ii) are correct.

(B) (ii) and (iii) are correct.

(C) (iii) and (iv) are correct.

(D) (i) and (iii) are correct.

Answer: (D)


Answer: (A)


40. During the process of milk boiling, the heater is to be put off before the bubble gets over spilled. The following controls are put in operation while switching off the heater. They are

I. Only proportional

II. Only integral

III. Proportional and derivative controls are followed.

IV. Only derivative

(A) I as well as II are followed.

(B) I as well as IV are followed.

(C) Only III is followed.

(D) I, II and IV are followed.

Answer: (B)


Q. Nos. 41 to 50:

Assertion – Reason type questions:

The following items consist of two statements, one labelled the ‘Assertion (A)’ and the other labelled the ‘Reason (R)’. You are to examine these two statements and decide if the Assertion (A) and the Reason (R) are individually true and if so, whether the Reason is a correct explanation of the Assertion. Select your answers to these items using the codes given below and mark your answer sheet accordingly.


(A) Both (A) and (R) are true and (R) is the correct explanation of (A).

(B) Both (A) and (R) are true but (R) is not the correct explanation of (A).

(C) (A) is true and (R) is false.

(D) (A) is false and (R) is true.


41. Assertion (A): An intrinsic semiconductor is doped lightly with p-type impurity. Its conductivity decreases till a certain doping level is reached.

Reason (R): The mobility of both holes and electrons decreases.

Answer: (A)


42. Assertion (A): Number of mesh current equations in a network depends upon the number of branches B and nodes N in a network.

Reason (R): Number of mesh current equations is B + N – 1.

Answer: (C)


43. Assertion (A): Offsets in op-amp are introduced due to mismatch at differential input stage. The offsets change with time and temperature.

Reason (R): The offsets must be removed as they introduce noise in a.c. signals.

Answer: (C)


44. Assertion (A): Dual slope A/D converter is the most preferred A/D conversion technique employed in most digital multimeters.

Reason (R): Dual slope A/D converter provides high accuracy and also suppresses the HUM effect on the input signal.

Answer: (A)


45. Assertion (A): The default address,for starting the execution of the program, is from 0000H. This is valid for Intel processors.

Reason (R): The starting address of RAM is from 0000H.

Answer: (C)


46. Assertion (A): The break; statement is used to exit from if statement.

Reason (R): In while (1) loop break; statement is put at the end of a loop.

Answer: (C)


47. Assertion (A): Magic Tee is a 4- junction hybrid Tee and displays power dividing properties in E and H plane and has advantage of being fully matched.

Reason (R): It has a hybrid junction about an imaginary plane bisecting two arms.

Answer: (A)


48. Assertion (A): In the super heterodyne receiver, the signal voltage is combined with local oscillator voltage and normally converted into a signal of a lower fixed frequency.

Reason (R): The intermediate frequency of receiving system may be neither low or high, but in a certain range between the two.

Answer: (A)


49. Assertion (A): PIN diodes are used as photo detectors. This is achieved by doping lightly doped in material in between p and n junctions.

Reason (R): These are used because higher frequency infra-red penetrate more deeply in the semiconductor material.

Answer: (C)


50. Assertion (A): Due to two metals with different coefficient of expansion, when the junction is formed, the junction produces a voltage corresponding to temperature.

Reason (R): The metals which are used for making thermocouples are non-homogeneous.

Answer: (B)


51. Arrange the following configurations of BJT in the increasing order of their input impedance.




IV. Darlington pair

(A) III, II, IV, I

(B) I, II, III, IV

(C) IV, III, II, I

(D) II, I, III, IV

Answer: (D)


52. The sequence to the venise a network and calculate current through the load is

(i) Obtain VTH or RTH

(ii) Remove the load

(iii) Put VTH and RTH in series

(iv) Connect the load in series

The correct sequence is

(A) (i), (ii), (iii), (iv)

(B) (ii), (i), (iii), (iv)

(C) (iii), (i), (iv), (ii)

(D) (iv), (iii), (i), (ii)

Answer: (B)


53. The correct order in which data is most reliably transmitted

(i) Current loop

(ii) V to F conversion

(iii) Voltage transmission

(iv) Digital data communication

(A) (iii), (i), (ii), (iv)

(B) (ii), (iv), (i), (iii)

(C) (i), (iv), (iii), (ii)

(D) (iv), (iii), (ii), (i)

Answer: (A)


54. Consider the Analogue to Digital convertion given below:

I. Successive approximation ADC

II. Dual-slope ADC

III. Counter method ADC

IV. Simultaneous ADC

The correct sequence of the ascending order in terms of speed of the above ADC’s is:

(A) I, II, III, IV

(B) II, I, III, IV

(C) IV, II, I, III

(D) III, II, I, IV

Answer: (B)


55. The following operations are done during the execution of an instruction:

(i) Decode

(ii) Fetch

(iii) Signal transfer

(iv) Execute

(A) (i), (ii), (iii), (iv)

(B) (ii), (i), (iv), (iii)

(C) (iii), (i), (ii), (iv)

(D) (ii), (i), (iii), (iv)

Answer: (B)


56. The correct sequence of hierarchy of operators is _____. From highest to lowest.

(i) – or +

(ii) ( )

(iii) / or *

(iv) * *

(A) (i), (iii), (iv)

(B) (ii), (iv), (iii)

(C) (ii), (iii), (i)

(D) (iv), (ii), (i)

Answer: (B)


57. Following are the mediums of communication:

(i) Sea water

(ii) Sky waves

(iii) Space waves

(iv) Glass fibers

The correct sequence of operating frequencies in increasing order is:

(A) (iv), (iii), (ii), (i)

(B) (i), (ii), (iii), (iv)

(C) (ii), (iii), (iv), (i)

(D) (iv), (ii), (iii), (i)

Answer: (B)


58. Following are the steps for A to D conversion of the signal:

(i) Quantization

(ii) Sampling

(iii) Filtering

(iv) Encoding

The correct sequence of A to D conversion is

(A) (i), (ii), (iii), (iv)

(B) (ii), (i), (iv), (iii)

(C) (iv), (iii), (ii), (i)

(D) (iii), (ii), (i), (iv)

Answer: (D)


59. Following are the detectors used in optical communication:

(i) Photo diode

(ii) Photo-transistor

(iii) Avalanche photodiode

(iv) Pin diode

Correct sequence of gain in decreasing order is given by

(A) (iii), (iv), (ii), (i)

(B) (iv), (iii), (ii), (i)

(C) (i), (ii), (iii), (iv)

(D) (iv), (ii), (iii), (i)

Answer: (A)


60. The correct sequence to be followed to build data acquisition system is by arranging the steps as follows:

(i) Transducer

(ii) Software development

(iii) Range of parameter

(iv) Signal conditioning

(A) (i), (ii), (iii), (iv)

(B) (iv), (iii), (ii), (i)

(C) (iii), (i), (iv), (ii)

(D) (ii), (iii), (iv), (i)

Answer: (C)


61. Match List – I with List – II.

List – I                                                List – II

a. Monostablemultivibrator                 1. No-stable state

b. Astablemultivibrator                       2. One-stable state

c. Free-running multivibrator              3. Two-stable state

d. Bistablemultivibrator                      4. Alternate high and low output


       a b c d

(A) 2 3 1 4

(B) 3 2 4 1

(C) 1 3 4 2

(D) 2 1 4 3

Answer: (D)


62. Match List – I with List – II and select the correct answer using codes given below:

List – I                                    List – II

a. Cut set                                 1. KVL

b. RC-differentiator                2. Branch voltage

c. Dual of KCL                       3. Frequency response

d. Bode plots                          4. High pass filter


       a b c d

(A) 2 4 1 3

(B) 3 2 4 1

(C) 4 3 1 2

(D) 1 2 4 3

Answer: (A)


63. Match List – I with List – II and select the correct answer using codes given below:

List – I                                    List – II

a. Duty cycle                           1. Variable voltage regulator

b. AGC                                   2. Astable multivibrator

c. LM317                                3. Voltage regulator

d. Crow-bar protection           4. FET


       a b c d

(A) 1 2 3 4

(B) 3 4 1 2

(C) 4 3 2 1

(D) 2 4 1 3

Answer: (D)


64. Match List – I with List – II and select the correct answer by using the codes given below the lists:

List – I                        List – II

a. Multiplexer              1. Sequential memory

b. De-multiplexer        2. Converts decimal number to binary

c. Shift-register           3. Data Selection

d. Encoder                  4. Routes out many data input with single data output


      a b c d

(A) 3 4 1 2

(B) 4 3 1 2

(C) 3 4 2 1

(D) 1 2 3 4

Answer: (B)


65. Match the following lists with correct ones:

List – I                        List – II

a. QUE                        1. Z flag not affected

b. DX                          2. Slow memory

c. DCX D                    3. Reg B

d. MUL/DIV              4. Variable port addressing


       a b c d

(A) 4 2 3 1

(B) 2 4 3 1

(C) 4 2 1 3

(D) 2 4 1 3

Answer: (D)


66. Match List – I with List – II and select the correct answer using codes given below:

List – I            List – II

a. if-then          1. Hex-data

b. % x              2. Garbage to calling function

c. gets( )          3. On-off controller

d. return;         4. Multi word string


       a b c d

(A) 3 1 4 2

(B) 2 3 4 1

(C) 1 2 3 4

(D) 4 3 2 1

Answer: (A)


Answer: (A)


68. Match the following:

List – A                       List – B

a. Modem                    1. Noise immunity better

b. FSK                         2. Error correctionwww.netugc.com

c. Codes                      3. Frequency shift keying

d. PCM                       4. Signal translator


       a b c d

(A) 4 3 2 1

(B) 3 2 1 4

(C) 2 1 3 4

(D) 1 4 2 3

Answer: (A)


69. Match List – I with List – II and select the correct answer using the codes given below:

List – I            List – II

a. Choppers     1. pn pn devices

b. SCR            2. V number

c. SMF            3. Speed control of d.c. motors

d. LASER       4. Quantum well


       a b c d

(A) 3 2 4 1

(B) 3 1 2 4

(C) 4 2 1 3

(D) 4 3 2 1

Answer: (B)


70. Match the following:

List – I                        List – II

a. 3½ digit                    1. Guarding/shielding

b. Pt – 100                   2. Bridge

c. RTD                        3. Temperature

d. Interference            4. DVM


a b c d

(A) 1 2 3 4

(B) 4 3 2 1

(C) 3 1 4 2

(D) 3 4 1 2

Answer: (B)


The World’s first microprocessor, 4004, was introduced by Intel in 1968. It was a 4 bit processor, but later it has introduced a new processor almost every year, like 8080, 8085, 8086, 8031 and 8051. Only 8086 processor handles 16 bit data and a micro-computer was developed based on this processor. Intel also introduced 80186, 80286, 80386, and 80486 and made possible to get mini computers and personal computers.

Other companies like Texas instruments, Motorola, Zilog and Analogue devices have specialized in signal processing processors, communication oriented processors, better architectural processor, and discrete signal processing devices.

All the advancements mentioned above are made possible because of continuous up gradation of VLSI technology. Some of the features like cache, pipelining and branch prediction have contributed for improving performance parameters, like execution speed, large memory, fast data transfers and reduction in number of instructions. A transformation has been seen from CISC to RISC.

Identification of application and its potential for marketing provides the opportunity to companies to produce ASICs sometimes. Digital Signal Processors are employed for processing streamed data of either voice or video data.


71. Expansion of ASIC is:

(A) Applied Science Integrated Circuit.

(B) Application Specific Integrated Circuit.

(C) Application Specific Internal Circuit.

(D) Application of Science and Integrated Circuit.

Answer: (B)


72. 8 bit date lines are not employed by the following processor:

(A) 8080

(B) 8085

(C) 8086

(D) 8051

Answer: (C)


73. Which one is not enhanced feature in spite of VLSI advances?

(A) Pipelining

(B) Branch prediction

(C) Power consumption

(D) Cache

Answer: (C)


74. Which of the following is not signalling processing?

(A) Date filtering

(B) Convolution

(C) Noise addition

(D) Date storing

Answer: (D)


75. Expansion of RISC:

(A) Reduced Integrated Systems Circuit

(B) Reduced Instructions Set Computer

(C) Reduction Integrated System Computer

(D) Reduced Instructions System Circuit

Answer: (B)