UGC NET Electronics Science Exam - June 2013 : Quiz & Solutions

Test your Preparation by solving UGC - NET June 2013 (Electronics Science) Exam Question Paper :

1. The p-n junction diode is a :
a. Passive device
b. Vacuum device
c. Unilateral device
d. Bilateral device

2. A semiconductor has ______ temperature co-efficient of resistance :
a. Zero
b. Positive
c. Negative
d. One

3. A JFET has :
a. One built-in diode
b. Two built-in diode
c. Three built-in diode
d. Four built-in diode

4. The superposition theorem is essentially based on the concept of :
a. Quality
b. Linearity
c. Reciprocity
d. Non-linearity

5. A counter that counts in binary from 0000 to 1010 is known as :
a. Binary counter
b. Decade counter
c. BCD counter
d. Mod-10 counter

6. A digital multiplexer is a/an :
a. Combinational circuit
b. Sequential circuit
c. Amplifier
d. Memory device

7. An 8086 has how many number of flags ? :
a. 5
b. 7
c. 9
d. 11

8. In 8085, microprocessor, the register which holds the address of the next instruction to be executed is
a. Instruction register
b. Stack pointer
c. Temporary register
d. Program counter

9. The Pentium III processor is a :
a. 16 bit processor
b. 32 bit processor
c. 64 bit processor
d. 128 bit processor

10. Demodulation is a process :
a. done at the transmitter
b. of filtering the carrier
c. of removing the sidebands
d. similar to modulation

11. The terms frequency pushing and pulling are related to :
a. Reflex Klystron
b. Two cavity klystron
c. Pulsed radar system
d. Magnetron

12. Out of the following memory types, one that is volatile is:
a. Magnetic disc
b. Ferrite core
c. Semiconductor ROM
d. Semiconductor RAM

13. When Q of an antenna increases, the bandwidth :
a. increases
b. decreases
c. stays constant equal to zero
d. stays constant equal to unity

14. The value of intrinsic-stand-off ratio of UJT should be
a. >1
b. <1
c. 0
d. 10

15. In a normal ECG waveform which wave has the maximum amplitude ?
a. P wave
b. R wave
c. Q wave
d. T wave

16. The output impedance in an ideal Op-Amp is :
a. 0
b. 20
c. 60
d. infinity

17. What will be the output of the following statements ? int a = 5, b = 2, c = 10, i = a > b Void main ( ) {print f(“hello”); main ( );}
a. 1
b. 2
c. infinity
d. 10

18. Which data communication method is used for sending data in both directions at the same time ?
a. Super duplex
b. Simplex
c. Half duplex
d. Full duplex

19. The highest data rate in fiber optic communication occurs in :
a. Single-mode fiber
b. Graded-index fiber
c. Multimode fiber
d. Co-axial cable

20. Routh’s array for a system is given below :
S4 1 3 5
S3 1 2 9
S2 1 5
S1 -3
S0 5
The system is
a. is stable
b. is unstable
c. is marginally stable
d. is absolutely stable

21. Assertion (A) : In a common base amplifier voltage gain is more than 1.
Reason (R) : In a common base amplifier current gain is less than 1.
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

22. Assertion (A) : Op-Amp is used for amplification of weak signals.
Reason (R) : To rectify EMG signals, precision rectifiers are used.
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

23. Assertion (A) : Gray is unweighted code.
Reason (R) : Gray code is not self complementary.
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

24. Assertion (A) : TDM and FDM accomplish the same end by different means.
Reason (R) : FDM involves simpler instrumentation as compared to TDM.
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

25. Assertion (A) : A SSB system is used for broadcasting applications.
Reason (R) : The saving of power in SSB system is = 75%.
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

26. Assertion (A) : Dual slope A/D converter is the most preferred conversion technique employed in most of the digital multimeters.
Reason (R) : Dual slope A/D converter provides high accuracy while at the same time suppresses the HUM effect on the input signal.
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

27. Assertion (A) :The system of propagation in waveguides is in accordance to field theory.
Reason (R) : The system of propagation in transmission line is in accordance with circuit theory.
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

28. Assertion (A) : For a function to be odd f(–x) = –f(x).
Reason (R) : If a function is odd, its Fourier series only contains cosine terms.
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

29. Assertion (A) : A number of thyristors operating in parallel can not share a common heat sink.
Reason (R) : For simultaneous firing of the thyristor opto isolators may be employed in the gate driving circuit.
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

30. Assertion (A) : ABCD parameters are transmission parameters.
Reason (R) : The relationship between input and output is given by:

 |V1| = | A  B |  |V2|
 |I1|   | C  D |  |I2|
 

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

31. Consider the following devices :
1. RTL
2. High Speed TTL
3. ECL
4. CMOS
The correct sequence of their decrease in power dissipation is
a. 3, 1, 2, 4
b. 3, 1, 4 ,2
c. 1, 3, 2, 4
d. 3, 2, 4, 1

32. Arrange the following in terms of their increasing conductivity :
1. Copper
2. Steel
3. Leather
4. Rubber
The correct sequence is
a. 4, 3, 2, 1
b. 4, 3, 1, 2
c. 3, 4, 2, 1
d. 2, 1, 3, 4

33. Following are the EM waves :
1. Red colour light
2. Blue colour light
3. Microwaves
4. X-rays
The correct sequence of decreasing order of wavelength is
a. 2, 4, 3, 1
b. 1, 3, 2, 4
c. 3, 1, 4, 2
d. 3, 1, 2, 4

34. Following are the process steps to fabricate an IC :
1. Crystal growth
2. Epitaxial growth
3. Photo etching
4. Diffusion
5. Vacuum evaporation of Aluminium
The correct sequence of fabrication is is free from race-around condition. Reason (R) : Master-Slave uses two JK flip-flops.
a. 1, 5, 3, 4, 2
b. 1, 2, 3, 4, 5
c. 1, 3, 2, 4, 5
d. 1, 2, 4, 3, 5

35. Following are the modulation/ multiplexing techniques :
1. AM
2. FM
3. CDMA
4. WDM
The correct sequence of carrier frequency in decreasing order is
a. 1, 2, 3, 4
b. 4, 3, 1, 2
c. 4, 3, 2, 1
d. 3, 4, 2, 1

36. Match List-I with List-II and select the correct answer using the codes given below the lists :

             List-I                      List-II
    (a) LED                    (i)  Heavily doped
    (b) APD                   (ii)  Coherent radiation
    (c) Tunnel diode         (iii)  Spontaneous emission
    (d) Laser                 (iv)  Current gain

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

37. Match List-I with List-II and select the correct answer using the codes given below the lists :

             List-I                              List-II
    (a) Cassegrain antenna               (i)  Large B.W.
    (b) Yagi antenna                    (ii)  Direction finding
    (c) Parabolic reflector antenna    (iii)  Radar
    (d) Loop antenna                    (iv)  Directional transmission

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

38. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                     List-II
	  (Band gap in eV)              (Materials) 
    (a) 0.67                    (i)  GaAs
    (b) 1.1                    (ii)  Cadmium sulphate
    (c) 1.4                   (iii)  Si
    (d) 2.4                    (iv)  Ge

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

39. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                     List-II
	(a) Voltage                      (i)  increases
        series                            input
        feedback                          impedance
        connection                     
    (b) Voltage                      (ii)  decreases the
        shunt                              input impedance 
        feedback
        connection                       
    (c) Current                      (iii)  increases the
	    series                              output impedance
        feedback
        connection                      
    (d) Voltage                       (iv) decreases the
        series                             output impedance
        feedback
        connection                      

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

40. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                        List-II
    (a) Electromyogram             (i)   Tracing brain waves 
    (b) Electrocardiogram          (ii)  Tracing of muscular waves
    (c) Electro-encephalogram      (iii) Measurement of air in lungs
    (d) Spirometer                 (iv)  A record of electrical activity of heart

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

41. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                           List-II
    (a) Removes ac ripple             (i)   Zener diode 
    (b) Supplies ac input voltage     (ii)  Filter capacitor
    (c) Constant dc output voltage    (iii) No output voltage
    (d) Filter choke inductor         (iv)  Power transformer

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

42. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                           List-II
    (a) Maxwells bridge             (i)   Measurement of unknown inductance 
    (b) Hay’s bridge                (ii)  Measurement of high Q of coils
    (c) Schering’s bridge           (iii) Precision measurement of capacitance
    (d) Weins bridge                (iv)  To measure frequency

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

43. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                        List-II
    (a) Gamma rays               (i)   400-700 nm
    (b) Visible light            (ii)  1-10 cm
    (c) Radiowaves               (iii) 3 e+3 m
    (d) Microwaves               (iv)  4 e-11 m

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

44. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                        List-II
	(Type of counters)        (No. of flip flops required)
    (a) Mod-6                   (i)   3
    (b) Mod-11                  (ii)  4
    (c) Mod-31                  (iii) 5

a. iii ii i
b. i ii iii
c. ii iii i
d. iii i ii

45. Match List-I with List-II and select the correct answer using the codes given below the lists :

         List-I                        List-II
		 (Units)                     (Quantity) 
    (a) ps/nm/km               (i)   Attenuation
    (b) dB/km                  (ii)  Magnetic field
    (c) cm2/v-s                (iii) Dispersion
    (d) Tesla                  (iv)  Mobility

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

Linked Items

[Read the passage below and answer the questions that follow based on your understanding of the passage];
p-i-n photodiode contains a layer of intrinsic semi-conductor material sandwiched between p-and-n regions. The depletionayer is wholly contained within the i region. Thickness of the intrinsic region can be adjusted to produce device with optimum sensitivity and frequency response. P-i-n photodiode is most common type of depletion layer photodiode. The other class of photodiodes, avalanche photodiodes, are reverse-biased p-n junction diodes that are operated at voltages above the breakdown voltage. Current multiplication of electron-hole pairs generated by the incident electromagnetic radiation, occurs due to avalanche process. The photomultiplication factor M is defined as ratio of the multiplied photocurrent Ipn to the photocurrent Ipho at voltage below breakdown where no avalanche multiplication takes place.

46. Semiconductors are sensitive to :
a. heat
b. magnetic field
c. light energy
d. all of the above

47. Which of the following elements is a semiconductor ?
a. Germanium
b. Copper
c. Carbon
d. Phosphorous

48. When a reverse bias is applied to a junction diode
a. potential barrier is lowered
b. majority carrier current is increased
c. minority carrier current is increased
d. potential barrier is raised

49. Photo-diode is reverse biased because
a. only one side is illuminated
b. majority swept are reverse biased across the function
c. reverse current is small as compared to photo current
d. reverse current is large as compared to photocurrent

50. Avalanche photodiodes are preferred over PIN diodes in optical communication systems because of
a. Speed of operation
b. Higher sensitivity
c. Larger bandwidth
d. Larger power handling capacity

Score =

Correct Answer: