UGC NET Electronics Science Exam - December 2004 : Quiz & Solutions

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Test your Preparation by solving UGC - NET 2004 (Electronics Science) Exam Question Paper :

1. Light falls on one end of a long open-circuited n-type semiconductor bar for low level injection the hole current is predominantly to :
a. Drift
b. Diffusion
c. Both drift and diffusion
d. Length of bar

2. Under high electric fields, in a semiconductor with increasing electric field :
a. The mobility of charge carriers decreases and saturates
b. The mobility of charge carriers increases.
c. The Velocity of charge carrier increases.
None of the above

3. The action of JFET in its equivalent circuit can be represented by :
a. Current controlled current source
b. Current controlled voltage source
c. Voltage controlled current source
d. Voltage controlled voltage source

4. The function is said to have :
a. even symmetry
b. odd symmetry
c. halfwave symmetry
d. quarterwave symmetry

5. The Laplace transform of is equal to :
a.
b.
c.
d.

6. A heat sink is generally used with a transistor to :
a. increase the forward current
b. decrease the forward current
c. compensate for excessive doping
d. prevent excessive temperature rise

7. The 555 timer can be employed in : (1) A monostable multivibrator (2) A bistable multivibrator (3) An astable multivibrator Of these statements
a. 1 & 2 are correct
b. 1 & 3 are correct
c. 2 & 3 are correct
d. 1, 2 & 3 are correct

8.A toggle operation is used :
a. with a gate circuit
b. with a flip-flop
c. without a flip-flop
d. with a counter

9. A multiplexer : (1) selects one of the several inputs and transmits to a single output (2) routes the data from a single input to one of many inputs (3) converts parallel data into serial data (4) is a combination circuit. Of these statements
a. 1, 2 & 4 are correct
b. 2, 3 & 4 are correct
c. 1, 3 & 4 are correct
d. 1, 2 & 3 are correct

10. Intel 8085 supports :
a. only isolated input output
b. only memory mapped input output
c. isolated input output and memory mapped input output
d. none of these

11. An I/O processor control the flow of information between :
a. Cache memory and I/O devices
b. main memory and I/O devices
c. two I/O devices
d. cache and main memories

12. In 8085, TRAP is :
a. always maskable
b. cannot interrupt a service subroutine
c. used for catastrophic events like temporary power failure
d. lowest priority interrupt

13. Which of the following is not a high level computer programming language ?
a. FORTRAN
b. MODED
c. COBOL
d. C++ language

14. Which microwave tube uses buncher and catcher cavities :
a. Magnetron
b. Klystron
c. Reflex Klystron
d. Tunneling wave tube

15. When a plane wave propagating through free space, the direction of the field : (A) E is perpendicular to the direction of propagation (B) H is perpendicular to the direction of propagation (C) E is perpendicular to the direction of the field H . Which is correct ?
a. 1 and 2
b. 2 and 3
c. 1 and 3
d. 1, 2 and 3

16. Given a carrier frequency of 100 KHz and a modulating frequency of 5 KHz the band width of AM transmission is :
a. 5 KHz
b. 200 KHz
c. 10 KHz
d. 20 KHz

17. A PAM signal can be detected by using :
a. an ADC
b. an integrator
c. a bandpass filter
d. a highpass filter

18. Which of the following semiconductor device acts like a diode and two resistor ?
a. Triac
b. Diac
c. SCR
d. UJT

19. In a thyristor, anode current is made up of :
a. Electrons only
b. Holes only
c. both electrons and holes
d. none of these

20. Which of the following semiconductor device acts like a diode and two resistor ?
a. speed
b. high voltage
c. transmission losses
d. micro wave power

21. A piezoelectric transducer converts :
a. Pressure to voltage
b. Pressure to velocity
c. displacement
d. vibration to kinetic energy

22. A LVDT has :
a. one primary coil and two secondary coils
b. two primary coils and one secondary coil
c. one primary coil and one secondary coil
d. two primary coils and two secondary coils

23. A strain gauge is a transducer which will convert :
a. Pressure into temperature
b. Pressure into velocity
c. Pressure into change of resistance
d. force into displacement

24. CMRR (Common Mode Rejection Ratio) for a differential amplifier should be :
a. Zero
b. Unity
c. Small
d. Large

25. Which of the following diode is used for frequency tuning ?
a. Varactor diode
b. Zener diode
c. Tunnel diode
d. Gunn diode

26. Match the List-I with List-II :

        List-I                      List-II

    (a) BJT                     (i) Pinch off effect
    (b) FET                    (ii) Frequency tuning
    (c) Varactor diode        (iii) Negative resistance
    (d) Tunnel diode           (iv) Punch through effect

a. (i)(iii)(ii)(iv)
b. (i)(ii)(iii)(iv)
c. (iv)(i)(ii)(iii)
d. (i)(iv)(iii)(ii)

27. Match the List-I with List-II :

        List-I                      List-II
     (a) Former                 (i) Produces deflecting torque
     (b) Coil                  (ii) Provides base for the coil
     (c) Core                 (iii) Makes the magnetic field radia
     (d) Springs               (iv) Provides controlling torque    

a. (i)(ii)(iii)(iv)
b. (i)(ii)(iv)(iii)
c. (ii)(i)(iii)(iv)
d. (ii)(i)(iv)(iii)

28. Match the List-I with List-II :

        List-I                      List-II
    (a) Passive Network         (i) Contains electrically separable passive circuit
    (b) Active Network         (ii) Contains electrically inseparable passive circuit
    (c) Lumped Network        (iii) Contains circuit elements without energy
    (d) Distributed Network    (iv) Contains circuit elements with energy sources

a. (iii)(iv)(i)(ii)
b. (i)(ii)(iii)(iv)
c. (ii)(i)(iv)(iii)
d. (iv)(i)(ii)(iii)

29. Match the List-I with List-II :

        List-I                                          List-II
    (a) Flip-Flop can be used as latch              (i)  D Flip-Flop
    (b) Flip-Flop can be used as delayed           (ii)  Master-slave Flip-Flop
    (c) Flip-Flop does not have race problem      (iii)  JK Flip-Flop
    (d) Flip Flop can be used as shift registers   (iv)  RS Flip-Flop

a. (iv)(i)(ii)(iii)
b. (ii)(iv)(i)(iii)
c. (i)(iii)(ii)(iv)
d. (iii)(i)(iv)(ii)

30. Match the List-I with List-II :

        List-I                        List-II
     (a) Parallel comparator        (i) Null balancing type
     (b) Successive approximation  (ii) Faster converter
     (c) Dual slope               (iii) Voltage dependent conversion type
     (d) Counter type              (iv) Integrating type  

a. (ii)(i)(iii)(iv)
b. (ii)(i)(iv)(iii)
c. (i)(ii)(iv)(iii)
d. (i)(ii)(iii)(iv)

31. Match the List-I with List-II :

        List-I                      List-II
    (a) Frequency modulation       (i) Envelop detection
    (b) Double sideband           (ii) Companding
       suppressed signal carrier
    (c) PCM                      (iii) Balance modulator
    (d) Amplitude modulation      (iv) Pre-emphasis and de emphasis

a. (i)(ii)(iii)(iv)
b. (i)(ii)(iv)(iii)
c. (iv)(iii)(i)(ii)
d. (iv)(iii)(ii)(i)

32. Match the List-I with List-II :

        List-I                      List-II
    (a) RC coupling             (i) High voltage gain and impedance matching
    (b) Inductive coupling     (ii) Ability to amplify dc and low frequency signals
    (c) Transformer coupling  (iii) Minimum possible non-linear distortion
    (d) Direct coupling        (iv) Low collector supply voltage can be used

a. (iv)(i)(iii)(ii)
b. (iii)(iv)(i)(ii)
c. (i)(ii)(iii)(iv)
d. (iv)(iii)(ii)(i)

33. Match the List-I with List-II :

        List-I                       List-II
    (a) LASER                   (i) Emits light of low intensity
    (b) Solar cell             (ii) Converts light energy into electrical energy
    (c) Photo diode           (iii) Deliver powers to load
    (d) LED                    (iv) Emits light of high intensity

a. (iv)(iii)(i)(ii)
b. (iii)(iv)(ii)(i)
c. (iv)(iii)(ii)(i)
d. (iii)(iv)(i)(ii)

34. Match the List-I with List-II :

 
           List-I                             List-II
     (a) Single mode optical fiber       (i) data rate is highest
     (b) Multi mode optical fiber       (ii) data rate is medium
     (c) Graded index optical fiber    (iii) data rate is lowest
     (d) Simple glass rod optical fiber (iv) data transfer not possible

a. (i)(iii)(ii)(iv)
b. (iii)(i)(iv)(ii)
c. (ii)(iv)(iii)(i)
d. (iv)(iii)(ii)(i)

35. Match the List-I with List-II :

 
        List-I                   List-II
    (a) LVDT                (i) Pressure
    (b) Bourdon gauge      (ii) Temperature
    (c) Strain gauge      (iii) Displacement
    (d) Thermistor         (iv) Stress

a. (iv)(iii)(ii)(i)
b. (iii)(ii)(i)(iv)
c. (iv)(i)(iii)(ii)
d. (iii)(i)(iv)(ii)

36. Assertion (A) : If a semiconductor is placed in a transverse magnetic field B and an electric field E is applied across its other two faces, then it would produce an electric current I in the direction perpendicular to both B and E
Reason (R) : Hall coefficient is proportional to the mobility of charge carriers in the semiconductor.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

37. Assertion (A) : The Wein bridge can be used for frequency measurement.
Reason (R) : The Wein bridge uses only capacitors and resistors.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

38. Assertion (A) :R-2R ladder type D/A converter has a higher speed of conversion than a weighted resistance D/A convertor.
Reason (R) : R-2R ladder type D/A converter uses a smaller number of components than the weighted resistance D/A converter.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

39. Assertion (A) : Bistable multivibrator can be used as flip flop.
Reason (R) : It has two stable states.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

40. Assertion (A) : Reflex klystron is made up of a single cavity.
Reason (R) : Velocity modulation occurs in the cavity.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

41. Assertion (A) : Optical fibers have broader bandwidth to conventional copper cables.
Reason (R) : The information carrying capacity of optical fibers is limited by Rayleigh scattering loss.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

42. Assertion (A) :A monostable multivibrator can be used to alter the pulse width of a repetitive pulse train.
Reason (R) : Monostable multivibrator has a single stable state.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

43. Assertion (A) : Radio and television receivers are generally of the superheterodyne type.
Reason (R) : Wireless communication is possible by receiving signals through super heterodyne receivers.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

44. Assertion (A) :A half-adder is faster than full adder.
Reason (R) : A half adder gives only one output while a full adder gives two outputs.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

45. Assertion (A) : Stimulated emission is the key to the operation of LASER.
Reason (R) : An important property of LASER radiation is its coherence, under which is meant the correlation between the phases of oscillation at different positions in space and at various moments of time.
a. Both (A) and (R) true and (R) is the correct explanation of (A)
b. Both (A) and (R) true but (R) is not the correct explanation of (A)
c. (A) is true but (R) is false
d. (A) is false but (R) is true

Linked Items

[Read the passage below and answer the questions that follow based on your understanding of the passage] Michael Faraday was one of the greatest of all scientific researchers. In 1845 he observed experimentally a relationship between electromagnetism and light. Twenty years later James Clerk Maxwell published "A Dynamical theory of the Electro-magnetic field". Starting with four basic relationship known as Maxwell's equations, he proved mathematically that electromagnetic waves could propagate through a nonconducting medium. He predicted a value of wave velocity. In early 1880 s Heinrich Hertz succeeded in verifying Maxwell's theory of electromagnetic wave through a brilliant series of experiments. The first application of electromagnetic waves was in the field of communications. The major contribution in this respect came from Sir Jagdish Chandra Bose of Calcutta, India and Guglielmo Marconi of Italy around 1895. Sir Jagadish Chandra Bose more than a century ago generated millimeter wave by using Galena detector. With the invention of telegraphy by Samuel Morse in 1844 and telephone by Bell and Gray in 1876, a more detailed study of electrical signals on transmission lines was needed. Thanks to the pioneering work of Barkhausin and Kurz on positive -grid oscillators (1919), and Hull on smooth-bore magnetron (1921), reliable microwave sources became a reality. A tube with 20 watts output at 3 GHz was constructed by British Scientists in 1936. A year later, the Varlan brothers at Stanford conceived the idea of velocity modulation of an electron beam. Microwave tube development in the forms of travelling wave tube and Reflex Klystron in 1930 s was given great impetus by the threatening war clouds over Europe precipitated by events surrounding world war II. The early 1960 s saw the emergence of Microwave integrated circuits and solid state microwave sources. The pioneering efforts of J.B. Gunn, W.T.Read, B.C. Deloach and many others led to the successful development of Gunn effect and Impatt type oscillators. Gunn diode is based on Gunn effect and an useful microwave source of power in the frequency range of 1 GHz to 30 GHz. Gunn diode exibits NDM due to transferred electron effect. With the development of satellite communication, microwave relay stations and further growth in commercial and military radars, microwave technology turned out to be billion-dollar industry. The International MTT symposium and the Transactions of the MTT are the major sources of information on development in the theory and practice of microwave engineering.

46. Four basic relationships known as Maxwall's equation do not contain the following law :
a. Gauss law
b. Ampere's law
c. Faraday's law
d. Non existance of magnetic monopoles

47. Microwave frequency extends from :
a. 0.1 GHz to 100 GHz
b. 1 GHz to 30 GHz
c. 1 GHz to 300 GHz
d. 50 MHz to 1000 GHz

48. Millimeter wave was demonstrated by Sir J.C Bose using a solid state detector. This detector was made of :
a. Silicon
b. Germanium
c. Galena
d. Carbon

49. The idea of velocity modulation of an electron beam was used to construct :
a. Gunn diode
b. Reflex klystron
c. Magnetron
d. Carcinotron

50. Gunn diode is based on :
a. Impact ionization and avalanche multiplication effect
b. Transferred electron effect
c. Velocity modulation effect
d. Current modulation effect

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