bel paper no 2

8/12/2019 bel paper no 2

1/21

BEL Placement Paper 2

(Technical-Electronics-IInd)

1. Resistivity of silicon in ohms cm. is approx. equal to

a. 5 !. 11" c. "#$ d. 1-%

". Rsistivity of&ermanium in ohms cm. is approx. equal to

a. 5 !. 1-1" c. 5$ d. 1-%

#. The num!er of free electrons'cu!ic cm intrinsic &ermanium at room temperature is approx. equal to

a. 1.511 !. ".511# c. 1 d. 51%

. The num!er of free electrons'cu!ic cm of intrinsic silicon at room temperature is approx. equal to

a. 1.511 !. ".511# c. 1 d. 51%

5. The for!idden ener*y *ap for silicon is

a. 1.1e+ !. %,e+ c. .,e+ d. 1.,e+

%. The for!idden ener*y *ap for &ermanium is

a. 1.1e+ !. %,e+ c. .,e+ d. 1.,e+

,. type material is formed !y the addition of the follo/in* (penta valent )atom in n to semiconductormaterial

a. 0ntimony

!. 0rsenic

c. hosphorous

d. 0ny of the a!ove

2. type material is formed !y the addition of the follo/in* 3Trivalent4 atom tn to semiconductormaterial

a. oron !. &allium c. Indium d. 0ny of the a!ove

. Impurity atoms that produces type material !y its addition in semiconductor is called

a. 6onar !. 0cceptor c. 7onductor d. Insulator


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1. Impurity atoms that produces type material !y its addition in semiconductor is called

a. 6onar !. 0cceptor c. 7onductor d. Insulator

11. 6ynamic resistance of a diode Rd is if volta*e chan*es is 6+d and the current chan*e is 6 Id

a. 6 +d ' 6 Id!. 6 Id ' 6 +d

c. 1 ' 6+d

d. 1 ' 6 Id

1". oint contact diodes are preferred at very hi*h frequency8 !ecause of its lo/ 9unction

a. 7apacitance and inductance

!. Inductance

c. 7apacitance

1#. Identify the circuit *iven !elo/

a. 06 *ate

!. :R *ate

c. Rectifier

d. :R *ate

1. Identify the circuit *iven !elo/

a. 06 *ate

!. :R *ate

c. Rectifier

d. :R *ate

15. 67 value of a ;alf /ave rectifier /ith Em as the pea$ value of the input is

a. .#12Em

!. .12Em

c. .512Em


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d. .%12Em

1%. 7han*e in


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d. one of these

"". Transition capacitance 7t of a +aricap diode /ith Bnee volta*e +t8 reverse volta*e +r and B8 theconstant !ased on semiconductor material and the construction technique C dependent on type of9unction is *iven !y

a. 1 ' B (+t D +r)'"

!. 1 ' B (+t D +r)

c. B ' (+t D +r)

d. B ' (+t D +r)1'

"#. 7t B ' (+t D +r) /here +t Bnee volta*e8 +r reverse volta*e8 B manufacturin* dependentconstant and dependent on type of 9unction8 for alloy 9unction the value of is

a. 1'# !. "'# c. 1'" d. 1'

". 7t B ' (+t D +r) /here +t Bnee volta*e8 +r reverse volta*e8 B manufacturin* dependentconstant and dependent on type of 9unction8 for diffused 9unction the value of is

a. 1'# !. "'# c. 1'" d. 1'

"5. In FGET8 the drain current Id is *iven !y (Idss drain H source saturation current +*s H &ate H sourcevolta*e8 +p the pinch off volta*e)

a. Idss31 H +p'+*s4

!. Idss(1 H +*s'+p)"

c. Idss31 H +*s'+p)

d. Idss(1 H +*s'+p)#'"

"%. The shado/ mas$ in colour tu!e is used to

a. Reduce -Ray emission

!. Ensure each !eam hits its o/n dots

c. Increase screen !ri*htness

d. rovide de*aussin* for the screen

",. Indicate /hich of the follo/in* si*nal is not transmitted in colour T+

a. J !. K c. R d. I


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"2. 0nother name for hori>ontal retrace in T+ receiver is the

a. Rin*in* !. urst c. 6amper d. Gly !ac$

". 0nother name for the colour sync in the colour T+ system

a. Rin*in* !. urst c. 6amper d. Gly !ac$

#. The ;+ anode supply for a picture tu!e of a T+ receiver is *enerated in the

a. Aains transformer

!. +ertical output sta*e

c. ;ori>ontal output sta*e

d. ;ori>ontal oscillator

#1. The output of vertical amplifier is

a. 6irect current

!. 0mplified vertical sync pulse

c. 0 sa/ tooth volta*e

d. 0 sa/ tooth current

#". In a transistor if 0lpha .28 current *ain is equal to

a. " !. 5 c. % d.

##. The active re*ion in the common emitter confi*uration means

a. oth collector and emitter 9unction is reverse !iased

!. The collector 9unction is for/ard !iased and emitter 9unction

c. The collector 9unction is reverse !iased and emitter 9unction is for/ared !iased

d. oth collector C emitter 9unction are for/ard !iased

#. The saturation re*ion in the common emitter confi*uration means that

a. oth collector C emitter 9unction are reverse !iased

!. The collector 9unction is for/ard !iased and emitter 9unction


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c. The collector 9unction is reverse !iased and emitter 9unction is for/ared !iased

d. oth collector C emitter 9unction are for/ard !iased

#5. The = of Red8 &reen C lue in 1= Lhite J is *iven !y

a. #=8 5=8 11=!. 5=8 #=8 11=

c. #=8 11=8 5=

d. ##.#=8 ##.5=8 #2.#=

#%. Equali>in* pulse /idth8 if ; is the ;ori>ontal sync rate

a. .% ; !. ., ; c. . ; d. .1% ;

#,. In a simple R7 net/or$ the !and/idth is equal to

a. 1'" p R7

!. R7 ' "

c. " 7 ' p R

d. " p ' R7

#2. The time constant of a R7 net/or$ is *iven !y

a. R7 !. 7'R c. R'7 d. one of these

#. Girst >ero crossin* of pulse frequency spectrum occurs at if d is the pulse /idth8 T is the pulserepetition rate

a. 1'd !. d'T c. T'd d. T

. The distortion less output characteristic of a net/or$ means

a. 7onstant amplitude and linear phase shift over frequency

!. @inear phase shift and amplitude need not !e constant

c. 0ny amplitude and phase

d. one of these

1. ?in*le side!and means suppressed


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a. 7arrier

!. 7arrier and one side !and

c. :ne side !and

d. one of these". In an amplitude modulated si*nal8 lo/er side !and frequency is equal to (if the carrier frequency isfc and modulation frequency is fm)

a. fm D fc !. fc H fm c. fm r fc d. fc ' fm

#. Aodulation index of the frequency modulation depends on

a. 0mplitude C frequency of the modulation si*nal

!. Grequency and amplitude of carrier si*nal

c. 7arrier frequency

d. one of these

. The L of the narro/ !and GA if modulatin* frequency is fm

a. # r fm !. " r fm c. ".5 r fm d. 1 r fm

5. Reactance tu!e modulator is $no/n for

a. GA !. 0A c. A d. 0A

%. and/idth and rise time product is

a. .#5 !. .5 c. .# d. .

,. Ener*y *ap8 @*8 for &ermanium at room temp 3#o B4 is

a. .,"e+ !. 1.1e+ c. 1.5#e+ d. ."e+

2. +olt equivalent of temperature +T8 at 11%o B is

a. .11+ !. .1+ c. 1.1%+ d. .1+

. Reverse saturation current of a &e.diode is in the ran*e of

a. m0 !. u0 c. n0 d. p0

5. 7ut-in volta*e + for silicon is approximately


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a. ."+ !. .%+ c. .+ d. 1.1+

51. Every 1o 7 rise in temp. the reverse saturation current

a. 6ou!les

!. ;alvesc. Triples

d. o chan*e

5". ;all effect /ith reference to Aetal or ?emiconductor carryin* a current I is placed in a transversema*netic field 8 an electric field E is induced in

a. arallel to

!. erpendicular to I

c. erpendicular to !oth C I

d. erpendicular to

5#. 1 e+ (electron volt) is equal toM

a. 1. r 1-" F

!. 1.% r 1-1 F

c. 1.% r 1-" F

d. 1.1% r 1-1 F

5. 6onar impurity is havin* a valency ofM

a. " !. # c. d. 5

55. 0cceptor impurity is havin* a valency of

a. " !. # c. d. 5

5%. Electron volt arises from the fact that if any electron falls throu*h a potential of 1 volt8 its $ineticener*y /ill

a. 6ecrease8 C potential ener*y /ill increase

!. Increase C potential ener*y decrease

c. e unaltered C potential ener*y decreases


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d. Increase C potential ener*y increase

5,. ;ole is created in a semiconductor material if one of follo/in* impurities are added

a. 0ntimony

!. 0rsenic

c. Indium

d. hosphorus

52. Excess electron is created !y

a. oran

!. &allium

c. Indium

d. 0rsenic

5. 0 snu!!er circuit is used across the ?7R to protect a*ainst

a. The di'dt of the anode current

!. The dv'dt turn on

c. @.di'dt of load inductance

d. one of these

%. &ermanium has the valency of

a. " !. # c. d. 5

%1. ?ilicon has the valency of

a. " !. # c. d. 5

%". ;ole acts as a free char*e carrier of polarity

a. e*ative

!. ositive

c. eutral


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d. one of these

%#. urst si*nal in T?7 system is 2 cycles of the frequency of

a. 7olour su! carrier

!. icture carrierc. ?ound carrier

d. one of these

%. 7olour su! carrier reference !urst is superimposed on the

a. ac$ porch of the each hori>ontal sync pulse

!. Gront porch of the each hori>ontal sync pulse

c. Gront porch of the each vertical sync pulse

d. ac$ porch of the each vertical sync pulse

%5. The la/ of mass action /ith reference to semiconductor technolo*y states that the product of freene*ative C positive concentration is a constant and

a. Independent of amount of donor and acceptor dopin*

!. 6ependent on amount of donor and independent of the amount acceptor impurity dopin*

c. 6epend on amount of !oth donor C acceptor impurity dopin*

d. one of these

%%. The snu!!er circuit used across ?7R is a simple

a. R-@ net/or$

!. R@7 net/or$

c. @7 net/or$

d. R7 net/or$

%,. To limit the rate of rise of ?7R anode current a small

a. Inductor is inserted in cathode circuit

!. Inductor is inserted in anode circuit


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c. 7apacitor is inserted in anode circuit

d. 7apacitor is inserted in cathode circuit

%2. Torque developed !y a 67 servo motor is proportional to the

a. roduct of po/er and time!. roduct of armature current and !ac$ emf

c. 0rmature volta*e and armature current

d. Gield volta*e and field current

%. roportional Inte*ral control

a. Reduces steady state error !ut reduces the for/ard *ain

!. Increases the for/ard *ain and reduces the steady state error

c. Increases the steady state error and increases the for/ard *ain

d. one of these

,. Increasin* the servo !and/idthM

a. Improves si*nal to noise ratio

!. Improves speed response and lo/ers si*nal to noise ratio

c. Improves po/er output

d. one of these

,1. otch filter is

a. @o/ pass filter

!. ;i*h pass filter

c. arro/ stop !and filter

d. arro/ pass !and filter

,". In T+ Receivers the Electron !eam deflection method used is

a. Electro static

!. Electro ma*netic


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c. Aa*netic

d. 0ll the a!ove

,#. In a line of si*ht communication the maximum ran*e R in miles !et/een the receiver antenna and

transmitter antenna of hei*ht ; in feet is approximatelya. R 1.# N;

!. R 1."# N;

c. R 1.5# N;

d. R ".# N;

,. In /avelen*th of the % A;> carrier frequency is

a. 1 metres

!. 15 metres

c. 5 metres

d. ".5 metres

,5. In standard T+ receivin* antenna the dipole element is

a. .5 of the /ave len*th

!. ."5 of the /ave len*th

c. 1.5 of the /ave len*th

d. 1. of the /ave len*th

,%. The characteristics of GET are similar toM

a. Triode

!. Tertode

c. entode

d. 6iode

,,. 7har*e coupled device is an array of capacitors /hose structure is similar toM

a. ?hift re*ister


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!. Glip-flop

c. 06 *ate

d. 0mplifier

,2. :perational amplifier characteristics are /hich of the follo/in*M

a. Infinite *ain

!. Infinite input impedance

c. :utput impedance is >ero

d. 0ll of the a!ove

,. The typical value of the open loop *ain in d of an amplifier at 67 /ith no feed!ac$ isM

a. to 1

!. 2 to

c. to 5

d. 5 to ,

2. The # d !and /idth means the frequency at /hich

a. The open loop volta*e *ain reduced to .,,

!. The open loop *ain reduced to unity

c. Aaximum volta*e of a si*nal is /ithout distortion

d. It is a medium /ave !and /idth of radio receiver

21. Rise time of an amplifier is defined as time required

a. To chan*e from to 1 = of its final value

!. To chan*e from to 5 = of its final value

c. To chan*e from 1 to = of its final value

d. To chan*e from 1 to 1 = of its final value

2". ;i*h speed amplifier desi*n emphasi>ed on


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a. Extremely small !and/idth

!. +ery slo/ response

c. Onity *ain !and/idth after 1 A;>

d. one of these2#. Tuned amplifier havin* the frequency ran*e !et/een

a. 15 B;> H 5 A;>

!. 1 ;> H 1 B;>

c. 1 B;> H 1" B;>

d. 5 A;> H 1 A;>

2. The resonance frequency of a tuned circuit made up of R8 @8 7 is *iven !y

a. 1'" pN@7

!. " pN@7

c. " p ' N@7

d. N@7 ' "

25. The volta*e follo/er can !e o!tained usin* operational amplifier

a. Lithout any feed!ac$

!. ?eries parallel feed!ac$ of unity

c. arallel feed!ac$

d. ?eries feed!ac$

2%. Gidelity of the amplifier is /hen

a. It is a linear amplifier

!. It does not add or su!tract any spectral components

c. It amplifier each component !y the same amount

d. 0ll of the a!ove

2,. Lhat /ould !e the output /hen t/o input sine /aves of frequency 5 B;> and 1 B;> passed


15/21

throu*h an amplifier in the medium si*nal

a. 5 B;> and 1 B;>

!. 1 B;> and " B;>

c. 5 B;> and 15 B;>d. 0ll of the a!ove

22. The important application of ?chmitt tri**er is

a. To convert slo/ly varyin* input volta*e to a!rupt volta*e chan*e

!. To convert a!ruptly varyin* input volta*e into slo/ly varyin* output

c. To chan*e the frequency of the input

d. one of these

2. Aeanin* of decodin* is

a. inary addition

!. 6ata transmission

c. 6emultiplexin*

d. ?tora*e of !inary information

. 0pproximately ho/ many num!er of *ates are incorporated in ??@ chip

a. 1"

!. 1

c. Excess of 1

d. Excess of 1

1. The circuit dia*ram represents /hich one of the follo/in*

a. ;alf adder

!. Gull adder

c. Exor *ate

d. 06 *ate


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". Glip flop cannot !e called as

a. ista!le multivi!rator

!. 1 it memory unit

c. latch

d. com!inational circuit

#. The important use of lo/ pass filter in po/er supply is

a. To *et the re*ulation in the output volta*e

!. To filter out the ripple frequency

c. To increase the current ratin*

d. To convert 07 into 67

. inary equivalent of the decimal num!er 15 is

a. 111

!. 1111

c. 111

d. 111

5. In /hich of the follo/in* *ate the output /ill !e hi*h /hen all the maintained at hi*h level

a. :R

!. 06

c. 06

d. E:R

%. Lhich of the follo/in* definition is true in the 6e Aor*anPs theorem

a. Aultiplication sym!ols are replaced !y addition sym!ol

!. 0ddition sym!ols are replaced !y Aultiplication sym!ol

c. Each of the terms are expressed in the complementary form


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d. 0ll of the a!ove

,. 2"1'76 code fro a decimal num!er 1 is

a. 1 1 11

!. 1111c. 1111

d. one of these

2. 7om!inational circuit are mainly characteri>ed !y

a. :utput depends upon the previous state C presents state

!. :utput depends upon the input at that particular instant

c. :utput depends upon the presents state C the cloc$ state

d. :utput does not depends upon the input at all

. 0 flip flop is defined as

a. 0 !ista!le device /ith t/o complementary outputs

!. It is memory element

c. It /ill respond to input and it is a !asic memory element

d. 0ll of the a!ove

1. Gour !it code is called

a. i!!le

!. yte

c. Lord

d. Re*ister

0ns/erM-

1. c

". a

#. a


18/21

. !

5. a

%. !

,. d

2. d

. a

1. !

11. a

1". c

1#. !

1. a

15. a

1%. a

1,. a

12. d

1. c

". !

"1. a

"". c

"#. c

". a

"5. !

"%. !

",. c


19/21

"2. d

". !

#. c

#1. d#". d

##. c

#. d

#5. a

#%. c

#,. a

#2. d

#. a

. a

1. !

". !

#. a

. !

5. !

%. a

,. a

2. !

. !

5. !

51. a

5". c


20/21

5#. !

5. !

55. !

5%. !

5,. c

52. d

5. !

%. c

%1. c

%". !

%#. a

%. a

%5. a

%%. d

%,. !

%2. !

%. a

,. !

,1. c

,". c

,#. !

,. c

,5. a

,%. c


21/21

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2. a21. c

2". c

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25. !

2%. d

2,. a

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