BEL Placement Papers
Test Paper - VIII
When a inductive coil connected to a 200 V, 50Hz ac supply
with 10A current flowing through it dissipates 1000 watts
then which of the following will have least value in ohms-
a.) Resistance
b.) Reactance
c.) Impedance
d.) None
Oscillator crystal are made of
a.) Silicon
b.) Germanium
c.) Quartz
d.) None
For small size, high frequency coils, the most common core
material is-
a. )Air
b. )Ferrite
c.) Powdered ion
d.) Steel
If we have a parallel plate capacitor of plate area 'A' and
plate separatoin t and having a capacity C and a metallic
plate r of area A and of negligible thickness is introduced
in the capacitor at a distance from either of the two plates
as shown in the given figure then the capacity of the
capacitor will become
a.)
b.) C
c.) 2C
d.) 4C
A superconductor is a
a.) A material showing perfect conductivity and Meissner
effect below a critical temperature
b.) A conductor having zero resistance
c.) A perfect conductor with highest di-magnetic
susceptibility
d.) A perfect conductor which becomes resistance when the
current density through it exceeds a critical value
When an inductor tunes at 200 KHz with 624 pF capacitor and
at 600 KHz with 60.4 pF capacitor then the self capacitance
of the inductor would be
a) 8.05 pF
b) 10.05pF
c.) 16.01pF
d.) 20.01pF
Sparking occur when a load is switched off because the
circuit has high
a.) Inductance
b.) Capacitance
c.) Resistance
d.) None
Sparking between contacts can be reduced by inserting a
a.) Resistance in the line
b.) Capacitor in series with contacts
c.) Capacitor in parallel with contacts
d.) None
RF amplifier of an A.M. receiver is normally biased in
a.) Class 'A'
b.) Class 'b'
c.) Class 'C'
d.) None
The value of gate voltage for the operation of enhancement
of only N channel MOSFET has to be
a.) High positive
b.) High negative
c.) Low positive
d.) Zero
The input gate current of a FET is
a.) a few microamperes
b.) negligibly small
c.) a few milliamperes
d.) a few amperes
In the following fig. with R = 30k, the value of current
through 2 K resistor is
a.) 25 mA
b.) 40 mA
c.) 25/16 mA
d.) 10 mA
A step recovery diode
a.) has on extremely short recovery time
b.) conducts equally well in both directions
c.) is mainly used as a harmonic generator
d.) is an ideal rectifiers of high frequency signals
In order to get maximum undistorted output signal from CE
amplifier with VCC 10V, the value of VCE (Q) should be
approximately-
a.) 0.1V
b.) 5V
c.) 10V
d) V
In a FET the electrode, which corresponds to collector in
bipolar transistor, is
a.) source
b.) drain
c.) gate
d.) none
The device which acts like an NPN and a PNP transistor
connected base to base and emitter to collector is
a.) Triac
b.) UJT
c.) Diac
d.) SCR
A typical optical fibre has
a.) High refractive index core and low refractive index
cladding
b.) Low refractive index core and high refractive index
cladding
c.) Both a and b
d.) None
In the following figure circuit diagram of an op-amp based
is shown. The ratio is equal to
a.) 9
b.) 11
c.) 10
d.) 21
When a loud speaker is connected across the terminals A and
B of the network shown in the fig. then its impedance to
obtain maximum power dissipation in it will be
a.) 3 j1
b.) 3 + j9
c.) 7.5 + j 2.5
d.) 7.5 j 2.5
In the lattice network, the value of R for the maximum power
transfer to the load
a.) 5
b.) 6.5
c.) 8
d.) 9
For a lossy transmission line short circuited at the
receiving end, the input impedance is given by (Z0 is the
characteristic impedance, Φ is the propagation constant and
l is the length of the line-
a.) Z0 cot h Φl
b.) Z0 cot Φl
c.) Z0 tan h.Φ l
d.) Z0 tan Φl
The approximate thickness of the radome wall should be
a.) l
b.) l/4
c.) l/2
d.) l/8
A relatively permanent information is stored in
a. ) ROM
b.) RAM
c.) PROM
d.) Volatile memory
The rise time of the RC network shown in the given figure is
approximately equal to
b.) RC
c.) 2RC
d.) 4RC
If in the network shown in the fig. initially a steady state
is attained by closing the switch 's' and then if the switch
is opened at t = 0, then the current i(t) through the
inductor will be
a.) cos50tA
b.) 2A
c.) 2cos100tA
d.) 2sin50tA
When the p network of figure I and T-network of figure
II are equivalent then the values of R1, R2 and R3 will be
respectively
a) 9W, 6W and 6W
b.) 6W, 6W and 9W
c.) 9W, 6W and 9W
d.) 6W, 9W and 6W
When the impedance matrices of a two port networks are given
by and , then if these two networks are connected in series
then the impedance matrix of the resulting two-port network
will be
d.) indeterminate
Joule/coulomb is the unit of -
a.) Electric field potential
b.) Potential
c .) Charge
d.) None of the above
The electric field line and equipotential lines-
a.) Are parallel to each other
b.)Are one and same
c.) Cut each other orthogonally
d.)Can be inclined to each other at any angle
For a lossy transmission line short circuited at the
receiving end, the input impedance is given by (When Z0 is
the characteristic impendence g is the propagation constant
and L is the length of the line
When two equal positive point charges are placed along X-
axis at X1 and X1 respectively then the electric field
vector at a point P on the positive Y-axis will be directed-
a.) In the +x direction
b.) In the x direction
c. ) In the +y direction
d.) In the y direction
The directions of and in TEM mode transmission line with
respect to the direction of propagation are-
a.) Both and are transverse to the direction of propagation
b.) is and are transverse and h has a component in the
direction of propagation
c.) is entirely transverse and has a component in the
direction of propagation
d. ) is entirely transverse and has a component in the
direction of propagation
The lowest TM mode in a rectangular waveguide of cross
section a x b with a>b will be-
a.) TM01
b.)TE10
c.) TM112
d.)TE11
When a transmitter in a free space radiates a mean power of
p watts uniformly in all directions then at a distance d
sufficiently far from the source in plane the electric field
E should be related to p and d as
. When a dipole antenna was radiating with some excitation
in free space radiating a certain amount of the power v if
then this antenna is immersed in a lake where water is
non-dissipative but has a dielectric constant of 81, then
the radiated power with the same excitation will be
a.) Decrease to finite non-zero value
b.)Remain the same
c. )Increase
d.)Decrease to zero
When a (75 j40)W load is connected to a coaxial line of Z0
= 75 W at 6MHz then the load matching on the line can be
accomplished by connecting-
a.) A short circuited stub at the load
b.)An inductance at the load
c. )A short circuited stub at a specific distance from the
load
d.)none of the above
As compared to analog multimeters, digital multimeters are
a.) less accurate
b.) more accurate
c.) equally accurate
d.) none.
When a signal of 10 mV at 75 MHz is to be measured then
which of the following instruments can be used
a.) VTVM
b.) Cathode ray oscilloscope
c.) Moving iron voltmeter
d.) Digital multimeter
Which of the following statement is true about two wattmeter
method for power measurement in three phase current ?
a.) power can be measured using two wattmeter method only
for star connected three phase circuits.
b.) when two meter show indentical readings, in the power
factor is 0.5.
c.) when power factor is unit, one of the wattmeter reads
zero
d.) when the reading of the two wattmeters are equal but of
opposite sign, then the power factor is zero
When a capacitance transducer has two plates of area 5cm2
each, separated by an air gap of 2mm than the displacement
sensitivity in pf/cm due to gap change would be
a.) 11.1
b.) 44.2
c.) 52.3
d.) 66.3
The Q of a radio coil
a.) is independent of frequency
b.) increases monotonically as frequency increases
c.) decreases monotonically as frequency increases
d.) increases upto a certain frequency and then decreases
beyond that frequency
When a generator of internal impedance and operating at 1GHz
feeds a load via a coaxial line of characteristic impedance
50 ohm then the voltage wave ratio on the feed line is
a.) 0.5
b.) 1.5
c.) 2.5
d.) 1.75
The coding system typically used in digital telemetry is
a.) PPM (pulse position modulation)
b.) PAM (pulse amplitude modulation)
c.) PCM (pulse code modulation)
d.) PDM (pulse duration modulation)
Radiation pyrometers are used for the measurement of
temperature in the range of
a.) -2000C to 5000C
b.) 00C to 5000C
c.) 5000C to 12000C
d.) 12000C to 25000C
In the given figure band structure is shown. It is of
a.) Gallium Avesenide (GaAs)
b.) Silicon (Si)
c.) Copper (Cu)
d.) Germanium (Ge)
When anode is positive with respect to cathode in an SCR,
the numbers of blocked p-n junction is
a.) 1
b.) 2
c.) 3
d.) 4
The circuit symbol for a GTO is
a. b.
c. d.
In the given fig. mark out the type of Cyclo converters
a.) 1 phase to 1 phase with continuous conduction
b.) 1 phase to 1 phase with discontinuous conduction
c.) step up device
d.) 3 phase to 1 phase device
In the given fig. A-1, C=5, m H and C=20 m F, C is initially
charged to 200 V. After the switch.
S is closed at t = 0 the
maximum value of current and the
time at which it reaches this value are respectively.
a.) 400 A, 15.707 mS
b.) 50 A, 30 mS
c.) 100 A, 62.828 mS
d.) 400 A, 31.414 mS
50. In the given circuit the maximum current in the main SCR
M can be-
a.) 200 A
b.) 170.7 A
c.) 141.4 A
d.) 70.7 A
The transfer function of an amplifier is given by
The high 3-db frequency of the amplifier will approximately
a.) 5850 KHZ
b.)585 KHZ
c.) 5850 HZ
d.)585HZ
In comparison to full wave rectifier with two diodes the
four divide bridge rectifier has the dominant advantage of -
a). Higher current carrying
b.)Lower ripple factor
c.) Higher efficiency
d.)Lower peak increase voltage require
Power output increase in a class-c amplifier-
a.) If the conduction angle decrease
b).If the conduction angle increase
c.) Are not governed by the conduction angle
d.)None of the above
A transistor with hie = 1.5 k and hfe = 75 is used in an
emitter follower circuit where R1 and R2 are used for normal
biasing . Approximate value of its current amplification
is-
a.)75
b.)76
c.)75/76
d.)-75
Amplifier of class B has high theoretical efficiency of 78.5
percent because-
a.) It is biased almost to saturation
b.)Its quiescent current is low
c.)Its output is an exact replica of its input
d.)It is biased well below cut off
The coupling that produces minimum interference with
frequency response is-
a.) Direct coupling
b.)Impedance coupling
c.) R C coupling
d.)Transformer coupling
In the circuit shown in the given figure Rf provides
a.) Current series feedback
b.)Current shunt feedback
c.) Voltage series feedback
d.)Voltage shunt feedback
Mark the correct relation for the junction transistor
Data in the serial form can be converted into parallel form
by using
a.) PISO shift register
b.) SOIP shift register
c.) SIPO shift register
d.) POIS shift register
PROMs are used to store-
a.) bulk information
b.) information to be accessed rarely
c.) sequence information
d.) relatively permanent information
The horizontal axis in a 3 bit unipolar D/A converter
represents-
a.) Output bit combination
b.) analog output voltage
c.) input bit combination
d.) none of the above
'Not allowed' condition in NAND gate SR flip flop is
a.) s = 0, R = 0
b.) s = 1, R = 1
c.) s = 0, R = 1
d.) s = 1, R = 0
Name the fastest logic family-
a) TTL
b.) RTL
c.) DCTL
d.) ECL
Equation corresponding to De Morgan's theorem in Boolean
Algebra is
a.) (A+B) (A+B) = AA + AB + BA + BB
c.) A + AB = A
d.) None of the above
In the given fig find radix of the system
a.) 2
b.) 4
c.) 6
d.) 8
Modems are used for data transmission telephone lines to
a.) increase the transmission capacity
b) improve noice performance
c.) incorporate error control coding
d.) eliminate dc component in the transmitted signal
The figure of a control system is shown. The maximum value
of gain K for which the system is stable is-
a.)
b.) 3
c.) 4
d.) 5
Identify the example of open-loop system-
a.) A windscreen wiper
b.) Aqualung
c.) Respiratory system of an animal
d.) A system for controlling Anti-rocket missiles.
Consider the following expressions indicating the step or
impulse response of an initially relaxed control system-
1. (5 4e-2+) u(t)
2. (e-2t +5) (u(t))
3 .V(t) + 8e-2t u(t)
4 . V(t) + 4e-2t 4(t)
Those which correspond to the step and impulse response of
the same system include-
a.) 1&3
b.) 1&4
c.) 2&4
d.) 1&4
A system is described by
To test its stability by Lyapunovs method the following V
functions are considered.
Mark the most suitable V-function in this case-
a.) Only V1
b.) Only V2
c.) Both V1 and V2
d.) Neither V1 nor v2
Identity the polar plot of a typical type zero system with
open loop transfer function
The scattering matrix of a magic tee shown in the given
figure is-
Which is the following relate to rational transfer function
of a system-
1. Ratio of Fourier transform of output to input with zero
initial conditions.
2. Ratio of Laplace transform of output to input with zero
initial conditions.
3. Laplace transform of system impulse response.
4. Laplace transform of system unit step response select the
correct answer using the codes given below.
Codes
a.) 1 and 4
b.) 2 and 3
c.) 1 and 3
d.) 2 and 4
For the signal g (t) 10 cos (50 pt) cos2 (150at)
The Nyquist sampling state in t seconds is
a.) 150 samples per second
b.) 200 samples per second
c.) 300 samples per second
d.) 350 samples per second
In the case of a 70 MHz 1F carries for a transponder band
width of 36 MHz; energy must lie between MHz.
a.) 34 and 106
b.) 52. And 88
c.) 106 and 142
d.) 34 and 142
Radar used to eliminate clutter in navigational application
is
a.) Pulse radar
b.) Tracking radar
c.) MTI radar
d.) Mono pulse radar
The 1.55 mm windows is not yet in use with fiber optic
systems because
a.) The attenuation is higher than at 0.85 mm
b) The attenuation is higher than at 1.3mm
c.) Suitable laser devices have not yet been developed
d.) It does not lend itself to wavelength multiplexing
Pre-emphasis in FM systems involves-
a.) Compression of the modulating signal
b.) Expansion of the modulating signal
c.) Amplification of lower frequency components of the
modulating signal.
d.) Amplification of higher frequency components of the
modulating signal.
In a terrestrial microwave system transmission of signals is
achieved through-
a.) reflection from the ionosphere
b.) line of sight mode
c) reflection from the ground
d.) diffraction from the stratosphere.
Casse grain feed is used with a parabolic reflector to
a.) increase the gain of the system
b). increase the bandwidth of the system
c.) reduce the size of the main reflector
d.) allow the feed to be placed at a convenient point.
In most microwave communication link rain drop attenuation
is caused due to-
a.) scattering of microwaves by water drops of specific
size.
b) scattering of microwaves by a collection of droplets
acing as a single body.
c.) absorption of microwaves by water and consequent heating
of the liquid
d.) absorption of the microwaves by water vapor in the
atmosphere.
Circuit in the given figure represents.
a.) an astable multivibrator
b.) A monostable multivibrator
c.) Voltage controlled oscillator
d.) Ramp generator
. . D = r is-
a.) Maxwell's 1st equation
b.) Maxwell's II equation
c.) Maxwell's III equation
d.) Maxwells IV equation
In a rectangular wave-guide which TM mode exists-
a.) TM00
b.) TM01
c.) Tm10
d.) TM11
In directional coupler a portion of power two velliry fram
port 1) to port 2) is coupled to.
a). port 4
b). port 3
c.) port 2.
d.) port 3 & 4.
For high power i.e. 10 w to 50 kw measurement
a.) Barometer are used
b.) Thermisters are used
c.) Calorimetric technique
d.) Calorimetric watt meter technique used
The difference between TWT & klystron is
a.) In TWT electrons are in contact with RF field for long
time & in klystron for short time
b.) In klystron electrons are in contact with RF field for
long time & in TWT for short time
c.) In klystron there is no contact in RF field & electrons
while in TWT there is contact
d.) In TWT phase is no contact is RF field & electrons while
in klystron there is contact
Which one is most suitable for transmission through wave
guide-
a.) Hown antennas
b.) Bioconical antennas
c.) helical antenna
d. )Discone
The skip distance of microwave is given by
a.)
b. )
c.)
d.)
How many general purpose registers 8085mp-
a.) 4
b.) 6
c.) 8
c.) 10
8085 mP has no. of addressing modes-
a.) 2
b.) 3
c.) 4
d.) 5
What will be status of z and c y flag after execution of SUB
A instruction
a.) z = 0, cy = 0
b.) z = 0, cy = 1
c.) z = 1, cy = 0
d.) z = 1, cy = 1
Microprocessor accept interrupt only if.
a.) interrupt flip flop disabled.
b.) when INTA signal is low.
c. ) interrupt flip flop enabled.
d.) none of above.
Microprogramming is a technique
a.) for programming the microprocessor
b.) for writing small programs efficiently
c.) for programming the control steps of computer
d.) for programming o/p / i/p
High level programs like C are converted into machine
language with the help of
a.) interpreter
b.) compiler
c.) operating
d.) system
(10110011)2 = (?)8
a.) 253
b.) 263
c.) 273
d.) 283
A Not gate at the output of AND gate converts AND gate into-
a.) NAND
b.) NOR
c.) AND
d.) NOPE.
The O/P of a logic gate is the gate must be-
a.) AND
b.) OR
c.) NAND
d.) X-OR
A symbol of JK flip flop is-
A demultiplener-
a.) has multiple i/p and single o/p
b.) has multiple i/p and multiple o/p
c.) has multiple i/p and multiple o/p
d.) has single i/p and single o/p
. Which of the following best describes the authour`s
attitude toward fairy tales ?
a.) fascination
b.) open approval.
c.) Indulgent tolerance.
d.) Scornful.
What type of sentence is this ?
Hurray! We won the match
a.) Exclamatory
b.) assertive
c.) Negative
d.) Affirmative
Before which of the following word will you put 'a'
a.) hour
b.) M. A.
c.) Umbrella
d.) Man
The noun form of 'fresh' is
a.) freshly
b.) freshen
c.) fresheners
d.) fresh itself
The word 'clang' is an example of
a.) Simile
b.) inversion
c.) onomatopoeia
d.) irony
The Forbes magazine acclaimed Azim Premji as richest India's
is the chairman of-
a.) Pentafour software
b) Infosys
c.) IBM
d.) Wipro
Bharat Ratna award for the year 2001 goes to-
a.) Lata Mangeshkar and Zakeer Hussain
b.) Zakeer Hussain and Bismillah Khan
c.) Bismillah Khan and Lata Mangeshkar
d.) Lata Mangeshkar and Ustad Amzad Ali Khan
Mr. George W-Bush takes over as ------ President of the
united states of America succeeding Mr. Bill Clinton-
a.) 42nd
b.) 43rd
c.) 40th
d.) 45th
New Chief Minister of Pondicherry is-
a.) T. Venkat Naidu
b.) K. Hari Harh
c.) N. Rengaswany
d.) M. Mudliar
No court has the jurisdiction to interfere with the election
process once set in motion by the Election commission. This
is enshrined in Article-
a.) 311
b.) 329
c.) 356
d.) 365
Ostrich is a-
a.) Running bird
b.) Flying bird
c) Swimming bird
d.) Migratory bird
The main atmospheric gas responsible for green house is-
a.) Oxygen
b.) Nitrogen
c.) Ozone
d.) Carbon-dioxide
Which of the following is not a Kharif Crop-
a.) Rice
b.) groundnut
c.) Sugarcane
d.) gram
The function of World Bank is to-
a.) Help in reconstruction and development of world economy
b.) Facilitate poor countries to trade on concessional rates
c.) Promote growth of international trade and equilibrium in
balance of payments
d.) Ease trade barriers and establish rule of fair trade
Speed of sound is maximum in-
a. )Water
b.) Air
c.) Steel
d.) Vacuum
Long years ago we made a trust with destiny. Whose words
are these-
a.) Subhash Chandra Bose
b.) Jawaharlal Nehru
c.) Lajpat Rai
d.) Bhagat Singh
Durand cup is associated with-
a.) Hockey
b.) Tennis
c.) Football
d.) Badminton
Rabindranath Tagore was awarded the Nobel Prize in
literature in the year.
a.) 1908
b.) 1910
c.) 1913
d.) 1914
India successfully conducted its first underground nuclear
experiment at Pokhran in Rajas than on-
a.) May 18, 1975
b.) May 20, 1974
c) May 17, 1974
d.) May 17, 1974
An emergency loan of $ 500 million to help reconstruct
infrastructure in earth quake devastated Gujarat approved
by-
a.) Asian development Bank
b.) World Bank
c.) Swiss Bank
d.) Reserve Bank of India
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