PAPER : BSNL JTO Model Test Paper (Unsolved)
The electric potential due to an electric dipole of length L at point distance r away from it will be doubled if the -
a. ) Length L of the dipole is doubled
b. ) r is doubled
c. ) r is halved
d ) L is halved
When a particular mode is excited in a waveguide there appears an extra electric component in the direction of propogation . The resulting mode is
a. ) Longitudinal electric
b. ) Transverse electromagnetic
c. ) Transverse magnetic
d ). Transverse electric
When for a transmission line the open circuit and short circuit impedance are 20W and 5 W respectively then the characteristic impedance of the line is -
a. ) 100 Ohms
b ). 50 Ohms
c. ) 25 Ohms
d. ) 10 Ohms
In an ideal transmission line with matched load, the voltage standing wave ratio and reflection coefficient are respectively -
a. ) 1 and 1
b ). infinity and 1
c ) infinity and 0
d. ) 1 and 0
When an electric charge of 100 coulombs is enclosed in sphere of radius 100 m then the electric displacement density ( in coulomb / m2) D is ?
a. ) 0.0833
b ). 0.833
c. ) 1.666
d. ) 10
For the dominant mode in a rectangular wavelength with breadth 10 cm, the guide wavelength for a signal of 2.5 GHz will be -
a. ) 12 cm
b. ) 15 cm
c. ) 18 cm
d. ) 20 cm
When the phase velocity of an electromagnetic waves depends on frequency in any medium, the phenomenon is called-
a. ) Scattering
c. ) Absorption
d. ) Dispersion
Antennas commonly used for microwave links are -
a. ) Loop antenna
b. ) Log-periodic antennas
c. ) Paraboloidal dishes
39. One of the following instrument which may be used to measure the optical activity of compounds is ?
a. )Infrared spectrometer
b. ) Atomic absorption spectrometer
c. ) Polarimeter
d. ) Flouroscope
Schering bridge measures ?
a. )Capacitance dielectric loss
b. ) Inductance
d. ) Mutual inductance
When a square wave is fed to an RC circuit, then ?
a. ) voltage across R is square and across C is not square
b. ) voltage across C is not square and across R is not square
c. ) voltage across both R and C are square
d. ) voltage across both R and C are not square
The time constant of the RC circuit is ?
a. ) less than the time period of the input square wave.
b ). much larger than the time period of the input square wave.
c. ) equal to the time period of the input square wave.
d ). none
Harmonic distortion for each frequency can be obtained by harmonic analyser of the ?
a. )heterodyne type
b. ) tuned circuit type
c. ) fundamental suppression type`
d. ) bridge circuit type.
A three phase wattmeter requires ?
a ). only two current coils and two pressure coils
b. )only one current coil and two pressure coil
c. ) only two current coils and one pressure coil
d. ) only current coil
A low pass filter circuit is basically ?
a. ) a differentiating circuit with low time constant
b. ) a differentiating circuit with large time constant.
c. ) an integrating circuit with low time constant.
d. )an integrating circuit with large time constant.
When a system is represented by the transfer function then the dc gain of this system is ?
Silicon based semiconductor device called thyristor was first fabricated by ?
a). Jell laboratories in U.S.A
b). Maxwell laboratories in U.S.A
c.) Bell laboratories in U.S.A
d). GEC laboratories in U.S.A
A semiconductor based temperature transducer has a temperature coefficient of ?2500mV/0C. This transducer is indeed a ?
b.) Forward biased pn junction diode
c. )Reverse biased pn junction diode
Which of the followings pairs of Telemetry situations and Modulation techniques and conditions is correctly matched-
a. )Pulse amplitude modulation Low amplitude signals
b. )Pulse position modulation For short distance when power is enough
c.) Pulse width modulation Power to be spent in telemetry is required to be low
d.) Pulse code modulation. Minimisation of interference effects.
The SCR ratings di/dt in A/m sec and dv/dt in n/m sec, may vary, respectively between-
a.) 20 to 500, 10 to 100
b. )both 20 to 500
c.) both 10 to 100
d.) 50 to 300, 20 to 500
Match the given controlled rectifiers with 50 Hz supply
a. )1 phase full converter with source inductance
b. )3 phase full converter
c.)3 phase semiconductor
d. )3 phase halls wave converter
For natural or forced commutation the cyclo converters (CCs) requires as under.
a) natural commutation in both step up and step down CCs
b.) forced commutation in both step up and step down CCs
c.) forced commutation in step up CCs
d). forced commutation in step down CCs
The peak inverse voltage in ac to dc converter system is highest in-
a). single phase full wave mid point converter
b). single phase full converter
c) 3 phase bridge converter
d). 3 phase half wave converter.
A single phase full converter feeds power to RLE load with R = 6 W L = 6 MH and E = 60 V. The ac source voltage is 230 V, 50 Hz, For continuous conduction, the average value of load current for a firing angle delay of 50 is
b). 14.81 A
c). 16.76 A
d.) 32.40 A
What is 215 complement of 00011100-
In C programming a expression contains relational operators, assignment operators and arithmetic operators if parentheses is absent then execution follows
a.) assignment, relational, arithmatic
b.) arithmatic, relational, assignment
c.) relational, arithmatic, assignment
d.) assignment, arithmatic, relational
In semiconductor memory information stored in form-
ip to Not gate gives o/p as-
a ) inversion of some bits
b.) 2's complement of ip
c.) 1's complement of ip
d.) o/p is some as ip
A negative logic means-
a .)logic 0 and 1 are represented by a +ve voltage respective
b). logic 0 and 1 are presented as ?ve and +ve voltage
c. )logic 0 voltage is higher than logic 1 voltage level
d.) logic 0 voltage is lower than logic 1 voltage level
For designing D flip flop from SR FF a circuit is aloud at 01p of SR FF is-
The transistor shown in fig is
a. ) Silicon, NPN with Ic = 0.5 mA
b.) Silicon PNP with Ic = 0.5 mA
c.) Germanium PNP with IE = 0.5 mA
d.) Germanium NPN with Ic=0.5 mA
A 20,000 Ohms per volt meter will deflect full-scale with a current of -
a.) 50 mA
b.) 50 mA
c.) 100 mA
d.) 1000 mA
A plate modulated class ?CRF power amplifier produces 100 KW of radiated power at 100 % modulation. The modulating audio amplifier supplies approximately ??? kW of this power-
An amplifier without feedback has a distortion of 15 % and gain of 40. When 10% negative feedback is applied the distortion will become-
a.) 50 %
b). -45 %
a.)Modulator at transmitting side and ditector at the receiving side
b.)Which deals with analog signals and shows digital information
c.)Analog to digital at transmitting side and digital to analog at a receiving side
d).A device which deals with digital signals only
Twisted ring and ring counters are examples of ?
a. )Synchronous counters
b.) Asynchronous counters
c.) both a and b
d.) None of the above
Specify Non characteristic flip flop in the following ?
a.) The outputs are complement of each other
b.) The flip flop has two input signals
c.) The flip flop has two output signals
d). The flip flop is a bistable devise with only two stable states
The voltage obtained when digital input is 001 is a 3 bit R-2R ladder DIA converter is-
d.) none of the above
Identify NOT an octal number-
The set of binary digits 01000100 represent's-
a.) number 6810 in a pure binary computer
b.) number 44 in 8421 BCD code
c) Both a and b
d.) None of the above
The system matrix of a continuous time system, described in the state variable form is ?
The system is stable for all values of x and y satisfying ?
a.)x < 1/2, y < 1/2
b). x < 0, y < 2
c. )x > 1/2 , y >0
d.) x < 0 , y < 1/2
The break away and break in point in the root locus for open loop transfer function G(S) H(S) = are located respectively at ?
a). ?2 and -1
b). ?2.47 and ?3.77
c.) ?4.27 and ?7.73
d.) ?7.73 and ?4.27
The type and order of the system whose Nyquist plot is shown in fig is-
The overall transfer function in a second order is given by-
Its resonant frequency is -
The detection of an AM waveform in an Envelope ?
a.)One side band and full amplitude carrier are needed
b.) Both side bands and full amplitude carrier are needed
c). Only two side bands are needed
d). Upper side band and part of carriers are needed
Satellite used for intercontinental communication is known as ?
b). Dom sat
c.) Mari sat
Mark out non submarine cable ?
a. )TAT ? 7
b.) INTELSAT V
d. )CANTAT 2
The capacity of an analog communication channel with 4kHz bandwidth and 15 dB SNR is approximately-
a). 20,000 bps
b). 16,000 bps
c.) 10,000 bps
d.) 8,000 bps
The blind speed of an MTl radar can be avoided by changing the-
a.) Carrier frequency
b.) Pulse repetition frequency
c. )Antenna rotation rate
d.) Transmitted power
The output voltage in a feedback series regulator circuit is regulated by controlling the-
a.) Magnitude of the input voltage
b.) Gain of the feedback transistor
c.) Reference voltage
d.) Voltage drop across the series pass transistor
Indicate the signal not transmitted in colour TV-
As frequency of singal increases-
a.) Directivity increases & beam width increases
b.) Directivity & beam width decreases
c.) Directivity increases & beam width decreases
d.) Directivity decreases & beam width increases
The number of hardware interupts (which require an external signal to interrupt) present in on 8085 mP are
Highest priority interupt is-
b. )RST 7.5
c. )RST 6.5
One instruction cycle means-
a. )Time require to execute set of instructions
b. )Time require to execute one instruction
c.) Time require to complete one operation of accessing memory, or I/o
d.) None of above
If the clock freq. is 5 mH3 how much time is required to execute on instruction of 18 T-states-
a. )3.6 msec.
b.) 36 m sec.
c.) 36 m sec.
d.) 36 sec.
In data transfer operation which flog get affected-
a. )zero flog
b. )carry flog
c. )sign flog.
CMP instruction comes under group -
a. )Data transfer
b. )Brouching operations
c). Machine control operation
d.) logical operations
The logic operation-
a.) are performed in relation to content of Accemce lotor
b).can be performed derectly with content of the register.
c.)are performed without content of a
d.)none of above.
What happen when PUSH instruction executed -
a.) data retrieved from stock to register
b.) data from register saved on the stock.
c.) 16 bit address of instruction saved on stock.
d.) 16 bit address from stock retrieved
SIM stands for-
a. ) serial interface memory
b.) set interrupt mosk
c. ) set if minus
d.) set internal memory
Maximum clock frequency required to operate 8085-
a. )2 MHz
b.) 3 MHz
c) 6 MHz
d. )9 MHz
ASCII code is-
a). 7 bit
b). 8 bit
d.) 32 bit.
In memory mapped I/O address lines are-
a. ) 8
The parity bit adding technique is used for -
c. )Error detection
a. )has multiple i/p and single o/p
b.) has single i/p and multiple o/p
c.) has multiple i/p and multiple o/p
d.) has single i/p and single o/p
Subroutines are useful-
a. )to reduce storage requirements
b.) to increase programming speed and reduce storage
c.) most applications are same
d.) but increases expense