ugc electronic science paper 2 june 2007

7/30/2019 UGC Electronic Science Paper 2 June 2007

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ELECTRONIC SCIENCE

PAPER-II

Note : This paper contains fifty (50) objective-type questions, each question carryingtw o (2) marks_ Attempt all of them.

1 . Monolithic transistors ar e fanned in th e epitaodal n-layer :

(A) by oxidation process

(B) by evaporation process

(C) by successive impurity diffusions

(D) i n open operation

2. The most popular fonn of IC package is :

(A) T0-5

(B) D IL

(C) Flat pack

(D) Disc pack

3. A unit ramp furu:tion when integrated yields :

(A) unit parabolic function

(B) unit ramp function

(C) unit doublet

(D) unit impulse function

4. The frequency range between tw o half power frequeru:ies is tenned as :

(A) damping coefficient

(B) selectivity

(C) bandwidth

(D) cut-off

5. Bootstrap is concemf


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6. The 4 - bit group that is used in excess- 3 code is :

(A) 0001

(B) 0011

(Q 0010

(D) 1110

7. In T flip flop, Q becomes Q when it s input is :

(A) O o r1

~ ) 0

(C)1

(D) 0 an d 1

8. Transistor amplifier configuration which simultsTif


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11. The input power factor of a cyclo converter is :

(A) high

~ ) low

(C) always equal to unity

(D) leading

12. A clipper:

(A) removes part of th e input signal

(B) modifies the shape of th e input signal

(C) increases DC value of the input signal

(D) reduces DC value of th e input signal

13. The carrier oscillator of a directly modulated FM transmitter generates a :

(A) sine wave

~ ) triangular wave

(C) ramp wave

(D) pwl&>

14. Pre-emphasis and de-emphasis circuits are used to :

(A) make the voice sound clearer

(B) increase the percentage of modulation

(C) increase the modulation index

(D) improve S/N ratio at the receiver

15. Feedback control systems are :

(A) low pass filters

(B) high pass filters

(C) band pass filters

(D) band reject filters

J - 8 8 0 7 4


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16. The effect of adcling poles and zeros can be studied quickly fo r deterrrrinktg phase andgain margin from :

(A) Nicholas plot

(B) Bode plot

(Q l\1agnitude versus phase plot

(D) Nyquistplot

17. In computer technology, 1M byte memory means :

(A) 10 00 000 bytes

(B) 10 00 024 bytes

(Q 10 24 000 bytes

(D) 10 4S 576 bytes

18. A n insbuction register is a storage for :

(A) location of data in memory

(B) location of instruction in memory

(Q binary code for the operation to be performed

(D) address of th e next insbuction to be executed

19. A n active lo w signal WTA is not needed from microprocessor to service which of thefollowing interrupt requesta ?

(A) TRAP

(B) INIR

(Q RST 7.5

(D) RST 5.5

20 . The address bus of Intel 8085 is 16 bit wide and hence the memory which can beaccessed by this address bu s is :

(A) 2 k bytes

~ ) 4 k bytes

(Q 10 k bytes

(D) 64 k bytes

J 8 807 P.T.O.


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(Questions 21 to 30); The followi..g items consi


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27 . Assertion (A) : The Wein bridge ca n be used fo r frequeru:y measurement.

Reason (R) : The Wein bridge uses only capacitors and resistors.

28 . Assertion (A) : The topdownsbuctured programming should be used fo r developingprogrammes.

Reason (R) : The top down sbuctured programming methodology enables us to getreadable and easily provable programs.

29 . Assertion (A) : A demultiplexer ca n be used as a decoder.

Reason (R) : A demultiplexer is built using NAND gates only.

30 .Assertion (A) :

LASERis a low-noise optical source.

Reason (R) : LASER operation is carried out at cryogenic temperatures.

3 1 . Measurement of a non-electrical quantity involves th e following four subsystems :

(i) Amplifier block

(ii) Display block

(iii) Instrumentation block

(iv) Transducer block

Th e correct sequence inwhich these

blocks occuris

:(A) (iv) (i) (rii) (li)

~ ) (iv) (ii) (>) (rii)

(Q (i) (lii) (ri) (lv)(D) (i) (li) (iii) (lv)

32. The following bands are used to identify the microwave frequency r ange1 G H z t o 2 6 G H z :

(i) K

(ii) L

(iii) s(iv) X

Th e correct sequence from lower frequency band to higher frequency band is :

(A) (i) (lv) (rii) (li)

~ ) (ii) (i) (iii) (lv)

(Q (ii) (iii) (lv) (i)(D) (ii) (iv) (>) (rii)

J 8 8 0 7 P.T.O.


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33 . Th e following semiconductors materials :

(i) Si

"

"

(ii) Ge

(iii) GaAS

(iv) ln P

Th e correct sequence in increasing order of th e majority carrier charge mobility is :

(A) (i) (li) (lii) (lv)

~ ) (iv) (i) (li) (iii)

(C) (i) (li) (lv) (iii)

(D) (i) (lv) (li) (iii)

Th e digital computer data storage media :

(i) Hard disk

(ii) Computer disk

(iii) RA M

(iv) Cache memory

Th e correctsequeru:e for the above media, th e digital data storage speed in descendingorder :

(A) (ii) (i) (lii) (lv)

~ ) (i) (li) (lii) (lv)

(C) (iv) (iii) (ii) (>)

(D) (iv) (iii) (i) (li)

Th e semiconductor devices :

(i) Tunnel diode

(ii) ffiT

(iii) ' JT

(iv) ll\1PATI

Th e correct sequence of their inheren t operating frequency in th e increasing order is :

(A) (ii) (iii) (i) (lv)

~ ) (iii) (ii) (i) (lv)

(C) (ii) (i) (lii) (lv)

(D) (i) (lv) (lii) (li)

J - 8 8 0 7


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36 . l\1atch List- I with List- II and select th e correct answer using the codes given belowthe list:

U s t - I U s t - II

'i) e - "(a) Value of Inductance(b) Power factor (ii)

roC

''c) Q factor (iii)

roC

(d) Value of Resistance (iv) F n 2 d

Codes ;

'"' (b) (c) (d)

(A) (iv) (ii) (lii) (i)

~ ) (iv) (iii) (ii) (i)

(C) (i) (li) (iii) (lv)

(D) (i) (lii) (lv) (li)

37 . l\1atch List- I with List- II and select the correct answers using the codes given belowth e list:


'"' ' JT (i) pinch-off effect

~ ) ffiT (ii) frequeru:y tmUng

(c) Varactor Diode (iii) Tlf


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38 . l\1atch Lis t - I with Lis t - II and select th e correct answer using the codes given belowthe list:

U s t - I

(Maximum Efficiency fu percent)

( ~ ) "~ ) 78.5

(c) '""(d) 00

Codes ;

'"' (b) (c) (d)

(A) (i) (li) (lii) (lv)

~ ) (ii) (i) (lv) (iii)

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

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

U s t - II

(Amplifier)

(i) O ass - B transformer-coupled

(ii) O ass - ARC-coupled

(iii) O ass - A transformer-coupled

(iv) O ass - D switching mode


U s t - I

( ~ ) Passive Network

~ ) Active Network

(c) Lumped Network

(d) Distributed Network

Codes ;

'"' (b) (c) (d)

(A) (iv) (ii) (iii) "') (i) (lii) (ii) (lv)

(C) (iii) (iv) (i) (ri)

(D) (i) (lv) (li) (iii)

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U s t - II

(i) Contain electrically separable passivecircuit elements

(ii) Contains electrically inseparable passivecircuit elements

(iii) Contains circuit elements without energysources

(iv) Contain circuit elements with energy

sources


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( ~ ) Conducting material (i) Alumina

~ ) Semi-conducting material (ii) Platinum

(c) Ferro-electric material (iii) Silicon

(d) Insulating material (iv) Barium Titanate

Codes ;

'"' (b) (c) (d)

(A) (iv) (i) (rii) (li)

~ ) (i) (lii) (ri) (lv)

(C) (iii) (iv) (i) (li)

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



( ~ ) Ampere's la w (i)dDV x H ~ j + -

"~ ) Faraday's la w (ii) V D ~ p

(c) Gauss' la w for electric field (iii) V B - 0

(d) Gauss' law for m a ~ t i cfield (iv)deV x E ~ - -

"Codes ;'"' (b) (c) (d)

(A) (ii) (iii) "' (lv)

~ ) (iv) (ii) "' (rii)

(C) (i) (lv) (rii) (li)

(D) (i) (lv) (ri) (rii)

J 8 8 0 7 n P.T.O.


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U s t - I U s t - I I

( ~ ) Crystal Osdllator (i) Local Osdllator

~ ) Reflex klystron (ii) Narrow-band Oscillator

(c) Saw-tooth generator (iii) Microwave Oscillator

(d) IF amplifier (iv) J\.fixer

Codes ;

'"' (b) (c) (d)

(A) (i) (li) (lii) (lv)

~ ) (ii) (iii) (iv) "'

C) (iv) (i) (lii) (ri)

(D) (ii) (iii) (i) (lv)



( ~ ) 8086 (i) 8 - bi t processor

~ ) 8085 (ii) Interlace chip

(c) 8255 (iii) 1 6 - bit processor

(d) 80486 (iv) 64 - bit processor

Codes ;

'"' (b) (c) (d)

(A) (iii) (i) (ii) (lv)

~ ) (i) (li) (lii) (lv)

(C) (iv) (i) (li) (iii)

(D) (ii) (i) (lv) (iii)

J 8 8 0 7


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44 . l\1atch List- I with List- II and select th e correct answer using th e codes given belowthe list:


( ~ ) Unearity (i) Superposition Theorem

~ ) Structure (ii) Norton's Theorem

(c) Equivalent circuit (iii) Tellegan's Theorem

(d) Bila tera l (iv) Reciprocity Theorem

Codes ;

'"' (b) (c) (d)

(A) (i) (li) (iii) (lv)

~ ) (i) (lii) (ri) (lv)

(Q (ii) (iii) (lv) (i)

(D) (i) (lii) (lv) (li)

45 . l\1atch List- I with List- II and select th e correct answer using the codes given below

the list:


( ~ ) Frequency modulation (i) Envelope detection

~ ) Double sided suppressed signal (ii) Compandingcarrier

(c) PC M (iii) Balanced modulation

(d) Amplitude modulation (iv) fu...emphasis and de-emphasis

Codes ;

'"' (b) (c) (d)

(A) (i) (li) (iii) (lv)

~ ) (i) (li) (iv) (rii)

(Q (iv) (iii) (i) (li)

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

J 8 8 0 7 " P.T.O.


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Para Phras&.g (Read the paragraph an d answer the questiom; 46 to 50) ;

The reflex klystron is a low-power, low frequeru:y, microwave osdllator_ I t has

an electron gun which produces an electron beam. Siru:e, th e device is short in length,

it does not require a focussing structure to counteract th e inter-electron repulsive forces_

The electron beam is accelerated toward th e cavity, which has a high positive voltage

applied to i t and acts as th e anode_ Th e electrons overshoot th e gap in this cavity and

continue on to the next electrode, which they Tlf


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48 . The purpose of cathode in microwave tubes is :

(A) to produce electrons

(B) to collect electrons(Q to reduce electrons

(D) to increase electrons

'9. The transit time in the repeller space of a reflex klystron must be n + 4 cycles to ensurethat :

(A) electrons are accelerated by th e gap voltage on their retum.

(B) returning electrons give energy to the gap oscillations.

(Q i t is equal to th e period of the cavity oscillations.

(D) th e repeller is not damaged by striking electrons.

50. The focussing structure is used in microwave tubes to :

(A) produce electron beam.

(B) counter the inter-electron repulsive forces.

(Q protect RF cavity

(D) protect repeller electrode

- 0 0 0 -

J 8 8 0 7 P.T.O.

ugc electronic science paper 2 june 2007

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