Exam Details

Subject electronic science
Paper paper 2
Exam / Course ugc net national eligibility test
Department
Organization university grants commission
Position
Exam Date December, 2013
City, State ,


Question Paper

1. The p-n junction diode is a

Passive device

Vacuum device

Unilateral device

Bilateral device
2. A semiconductor has temperature co-efficient of resistance

Zero
Positive

Negative
One
3. A JFET has

One built-in diode

Two built-in diode

Three built-in diode

Four built-in diode
4. The superposition theorem is essentially based on the concept of

Quality

Linearity

Reciprocity

Non-linearity
5. A counter that counts in binary from 0000 to 1010 is known as

Binary counter

Decade counter

BCD counter

Mod-10 counter
6. A digital multiplexer is a/an

Combinational circuit

Sequential circuit

Amplifier

Memory device
7. An 8086 has how many number of flags

5

7

9

11
8. In 8085, microprocessor, the register which holds the address of the next instruction to be executed is

Instruction register

Stack pointer

Temporary register

Program counter
9. The Pentium III processor is a

16 bit processor

32 bit processor

64 bit processor

128 bit processor
10. Demodulation is a process

done at the transmitter

of filtering the carrier

of removing the sidebands

similar to modulation
11. The terms frequency pushing and pulling are related to

Reflex Klystron

Two cavity klystron

Pulsed radar system

Magnetron
12. Out of the following memory types, one that is volatile is

Magnetic disc

Ferrite core

Semiconductor ROM

Semiconductor RAM
ELECTRONIC SCIENCE
13. When Q of an antenna increases, the bandwidth

increases


decreases


stays constant equal to zero


stays constant equal to unity



14. The value of intrinsic-stand-off ratio of UJT should be






0 (zero)

10



15. In a normal ECG waveform which wave has the maximum amplitude

P wave

R wave

Q wave

T wave



16. The output impedance in an ideal Op-Amp is

Zero

20 O

60 O

infinity



17. What will be the output of the following statements

int a b c 10, i a b

Void main

{print f("hello"); main

1


2


infinite number of times


10



18. Which data communication method is used for sending data in both directions at the same time
Super duplex


Simplex


Half duplex


Full duplex



19. The highest data rate in fiber optic communication occurs in

Single-mode fiber


Graded-index fiber


Multimode fiber


Co-axial cable



20. Routh's array for a system is given below

S4 1 3 5
S3 1 2 9
S 2 1 5
S1
S0 5
The system is


Stable


Unstable


Marginally stable


Conditionally stable


21.
Assertion In a common base amplifier voltage gain is more than 1.

Reason In a common base amplifier current gain is less than 1.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.
22.
Assertion Op-Amp is used for amplification of weak signals.

Reason To rectify EMG signals, precision rectifiers are used.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.
23.
Assertion Gray is unweighted code.

Reason Gray code is not self complementary.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.
24.
Assertion TDM and FDM accomplish the same end by different means.

Reason FDM involves simpler instrumentation as compared to TDM.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.

25. Assertion A SSB system is used for broadcasting applications.'

Reason The saving of power in SSB system is 75%.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.


26. Assertion Dual slope A/D converter is the most preferred conversion technique employed in most of the digital multimeters.

Reason Dual slope A/D converter provides high accuracy while at the same time suppresses the HUM effect on the input signal.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.


27.
Assertion :The system of propagation in waveguides is in accordance to field theory.

Reason The system of propagation in transmission line is in accordance with circuit theory.


Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.

28.
Assertion For a function to be odd

Reason If a function is odd, its Fourier series only contains cosine terms.


Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.

29.
Assertion A number of thyristors operating in parallel can not share a common heat sink.

Reason For simultaneous firing of the thyristor opto isolators may be employed in the gate driving circuit.

Both and are true and is the correct explanation of

Both and are true, but is not the correct explanation of

is true and is false.

is false and is true.

30.
Assertion ABCD parameters are transmission parameters.

Reason The relationship between input and output is given by
applications.
[V1 B C [V1 I2]

31.

The correct sequence of their decrease in power dissipation is

4


4


4


1


32. Arrange the following in terms of their increasing conductivity

1 Copper
2 Steel
3 Leather
4 Rubber

The correct sequence is

1


2


1


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

1


4


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

2


5


5


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

4


2


1


1



36. Match the following

List I List II
a. LED i. Heavily doped

b.APD ii. Coherent radiation

c. Tunnel iii. Spontaneous diode emission

d.Laser iv. Current gain


The correct sequence is given by

a b c d

ii i iii iv


iv iii ii i


iii iv i ii


iii ii i iv


37. Match the following

List I List II
a. Cassegrain i. Large B.W. antenna

b.Yagi antenna ii. Direction finding

c. Parabolic iii. Radar reflector antenna

d.Loop antenna iv. Directional transmission

a b c d

i iv ii iii


iii i iv ii


ii iv iii i


iii ii iv i


38. Match the lists
List I (Band gap in eV) List II (Materials)

a. 0.67 i. Ga As

b.1.1 ii. Cadmium sulphate

c. 1.4 iii. Si

d. 2.4 iv. Ge

The correct matching order is

a b c d

iv iii i ii


iii ii i iv


iv i iii ii


ii iii i iv


39. Match the following
Match the following
List I List II
a. Voltage series feedback connection i. increases input impedance
b. Voltage shunt feedback connection ii. decreases the input impedance
c. Current series feedback connection iii. increases the output impedance
d. Voltage series feedback connection iv. decreases the output impedance

a b c d
iv ii iii i


iv ii i iii


i iii iv ii


i ii iii iv



40. Match the following lists
List I List II
a. Electro- i. Tracing brain waves
myogram
b. Electro­cardiogram ii. Tracing of muscular waves

c. Electro- iii. Measurement of air in lungs
encephalogram
d. Spirometer iv. A record of electrical activity of heart

a b c d

i ii iii iv


i iv iii ii


i iv ii iii


iv iii i ii



41. Match the following

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 b c d
ii iv i iii

i iv iii ii

iv i ii iii

ii iii i iv



42. Match the following 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 b c d
i ii iii iv

iv iii ii i

iv ii iii i

i iii ii iv
43. Match the following lists

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

iv iii ii i

iv i iii ii

ii iii iv i

44. Match the List I and List II

List I (Type of counters) List II (No. of flip flops required)

a. Mod-6 i. 3
b. Mod-11 ii. 4
c. Mod-31 iii. 5

a b c

iii ii i

i ii iii

ii iii i

iii i ii
45. Match the following lists
List I (Units) List II (Quantity)

a. ps/nm/km i. Attenuation
b. dB/km ii. Magnetic field
c. cm2/v-s iii. Dispersion
d. Tesla iv. Mobility

a b c d
iv i ii iii

iii i ii iv

iii i iv ii

i iv iii ii

photodiode contains a layer of intrinsic semi-conductor material sandwiched between p-and-n regions. The depletion layer is wholly contained within the i region. Thickness of the intrinsic region can be adjusted to produce device with optimum sensitivity and frequency response. 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 Mpn is defined as ratio of the multiplied
photocurrent I to the photocurrent Ipho at pmvoltage below breakdown where no avalanche multiplication takes place.

46. Semiconductors are sensitive to

heat


magnetic field


light energy


all of the above

47. Which of the following elements is a semiconductor

Germanium

Copper


Carbon


Phosphorous


48. When a reverse bias is applied to a junction diode

potential barrier is lowered


majority carrier current is increased


minority carrier current is increased


potential barrier is raised


49. Photo-diode is reverse biased because

only one side is illuminated


majority swept are reverse biased across the function


reverse current is small as compared to photo current


reverse current is large as compared to photo current


50. Avalanche photo diodes are preferred over PIN diodes in optical communication systems because of

Speed of operation


Higher sensitivity


Larger bandwidth


Larger power handling capacity


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