Smart series most repeated MCQs of all NTS electrical engineering tests for post of Junior engineer/SDO in WAPDA NTDC,MEPCO,IESCO,PESCO and all DESCOS.
- The field lasts as long’ as current is flowing through the conductor
A. Gravitational
B. Electric
C. Magnetic
D. Kinetic Ans. C
- Waves which do not require material medium for their propagation are called
A. Electromagnetic
B. Electrostatic
C. Electrical
D. Mechanical Ans. A - SCR Is a device having layers and _ Junctions.
A. Four, three
B. Three, four
C. Three, two
D. Four, two Ans. A - The AC motors used in servo applications Is a
A. Single phase Induction motor
B. Two phase Induction motor
C. Three phase induction motor
D. Synchronous motor Ans. B - Transfer of ASCII codes from a microprocessor to a printer must be done on handshake basis because
A. open collector buffers are used on a signal & data line
B. Microprocessor can send characters much faster than printer can print them
C. Sometimes parallel printer in a system don’t have BIOS procedure
D. Both A and C Ans. B - Which is not a type of key switch?
A. Mechanical key switch
B. Capacitive key switch
C. Hall effect key switch
D. Maxwell’s key switch Ans. D - Specifying the kind of Input, processing and output required for a program occur when
A. Defining the problem
B. Planning the problem
C. Flowcharting the problem
D. Coding the problem Ans. A - In bus topology, what is ‘backbone’?
A. Hup
B. TAP
C. Log cable
D. Backup server Ans. C
- Which statement is not true about VHDL (VHSIC hardware description language)?
A. VHDL is an IEEE standard language
B. VHDL is strongly typed language
C. VHDL is case sensitive
D. VHDL Is developed as a part of very high-speed integrated circuit (VHSIC) Ans. C - The main drawback of a feedback system is
A. Inaccuracy
B. Inefficiency
C. Instability
D. Insensitivity Ans. C - Transient response of system is basically due to
A. Coupling
B. Forces
C. Friction
D. Stored energy Ans. D - If current and voltage are out of phase by 90 degree then power is
A. Zero
B. Minimum
C. Maximum
D. √3 VI Ans. A - The instantaneous value of sinusoidal AC current at 45o Is called
A. Peak to peak value
B. RMS value
C. Peak value
D. Average value Ans. B - Which wave has the least value of form factor?
A. Square wave
B. Triangle wave
C. Sine wave
D. Rectangle wave Ans. A - The unit of Inductive susceptance is
A. Siemens
B. mH
C. Henry
D. Ohm Ans. A
- When sole purpose of AC is to give heat then selection of conductor is based on
A. Peak value of current
B. Average value of current
C. RMS value of current
D. None Ans. C - The power factor of DC supply voltage is always
A. Unity
B. Zero
C. infinite
D. None Ans. A - Potential barriers are measured in
A. Volts
B. ‘Amps
C. Ohms
D. Coulombs Ans. A - Transistor means transfer of
A. Transfer of resistance
B. Transfer of capacitance
C. Transfer of inductance
D. None Ans. A - Depletion region carries
A. Positive charge
B. Negative charge
C. No charge
D. None of above Ans. C - Which is not an integrating instrument
A. Ampere hour meter
B. Watt hour meter
A. Voltmeter
C. Odometer Ans. C - The memory unit using only gates is
A. RAM
B. ROM
C. Core
D. Disc Ans. A - Ladder network used in digital to analog converter is
A. R-C ladder
B. R-2R ladder
C. R-L ladder
D. R-2L ladder Ans. B - No of digits in octal system is
A. 2
B. 8
C. 16
D. 18
ꞏAns. B - Which of the following binary numbers is equal to decimal number 10?
A. 1000
B. 1001
C. 0101
D. 1010
Ans. D - In DLD, a function that includes all the 2n min terms is equal to the logic
A. 0
B. 1
C. Infinity
D. 22n – l
Ans. B - Which triggering method is used for flip flop?
A. Master slave
B. King slave
C. Boss employ
D. None Ans. A - How many general purpose registers the execution unit has?
A. 2
B. 8
C. 12
D. 18 Ans. B - 8086 allows to set aside an entire 64k-byte segment as stack. The upper 16 bits of the starting address for this segment are kept in
A. Stack pointer
B. Data register
C. Segment register
D. All of above Ans. C - When all the terms in a row of Routh array are zero, the characteristic equation has roots on
A. Positive real axis
B. Negative real axis
C. Imaginary axis
D. Real axis Ans. C - Addition of poles in a transfer function causes
A. Lead compensation
B. Lag compensation
C. Lead lag compensation
D. Interval compensation Ans. B - If a system is critically damped and the gain is increased then system becomes
A. Over damped
B. Under damped
C. Oscillatory
D. Remains critically damped Ans. B - Which cannot be treated as an amplifier in control system?
A. DC generator
B. DC motor
C. Metadyne
D. Amplidyne Ans. B - In PCM system, quantization noise depends upon
A. Number’ of quantization levels only
B. Sampling rate
C. Index number
D. Both B and C Ans. A - Coupling used In Stoneman transmission bridge is
A. Resistive
B. Capacitive
C. Inductive
D. Combination of all Ans. B - One can provide two or more voice circuits on same carrier by using
A. DSB-SC
B. SSB with pilot carrier
C. ISB systems
D. SSB-BC system Ans. C - Frequency frogging is used in carrier system to
A. Conserve frequencies
B. Reduce distortion
C. Reduce crosstalk
D. Destroy frequencies Ans. C - Video transmission In TV broadcast is usually on
A. FM
B. PM
C. AM
D. SM Ans. C - In FM power has the modulation Index that
A. Increases
B. Decreases
C. Remains constant
D. Become zero Ans. C - A single flip flop can be constructed by using which digital gate
A. NANO
B. OR
C. NOR
D. AND Ans. A - Duration of pulse response is finite for
A. FIR filters
B. IIR filters
C. Electronic
D. ‘None Ans. A - For N-channel MOSFET terminal acts as a control electrode
A. Gate
B. Source
C. Drain
D. All Ans. A - Graphical difference between nFET and pFET is
A. Inversion bubble at the gate
B. Inversion bubble at the source
C. Inversion bubble at the drain
D. All Ans. A - Functionality of PLC contains
A. Sequential control relay
B. Process control relay
C. Distributed control relay
D. All of above Ans. D
- Injection laser is a device
A. Breakdown
B. Avalanche
C. Threshold
D. None of above Ans. B - Quality factor (Q-factor) of tuned circuit ls referred to as which property
A. Selectivity
B. Sensitivity
C. Fidelity
D. Connectivity Ans. A - If scale of voltmeter is uniform its type is
A. Hotwire
B. Induction
C. Moving coil permanent magnet type
D. Moving coil dynamometer Ans. C - Voltage applied across parallel RLC circuit is 100V, what is the resonant frequency when inductance is 0.1 H, capacitance is 0.1 μF and resistance ls 100 ohms
A. 1.259 KHz
B. 1.359 KHz
C. 1.539 KHz
D. 1.739 KHz Ans. C - The flag register in 8051 microcontroller is
A. A, Program status word
B. Memory register
C. Bit status
D. Location of data Ans. A - An oscillator converts which type of input to AC waveform signal
A. AC power input
B. DC power input
C. Both AC and DC power inputs
D. None of above
Ans. B
- Consistency of an instrument is related with
A. Precision
B. Accuracy
C. Validity
D. Reliability Ans. D - When an electric current passes through a bucket full of water, lot of bubbling is observed. This suggests that the type of supply is ꞏ
A. A.C
B. D.C
C. Can be any of these
D. None Ans. B - What happens to the resistance of carbon filament lamp as the applied voltage ls increased
A. Increases
B. Decreases
C. Remains same
D. None of above Ans. B - A 6 KHz sinusoidal voltage Is applied to a series RC circuit. The frequency of voltage across the resistor is
A. 0 Hz
B. 12 kHz
C. 6 kHz
D. 18 kHz Ans. C - When the frequency of source voltage decreases, the impedance of parallel RC circuit
A. Increases
B. Decreases
C. Does not change
D. Decreases to zero Ans. A - In a complex plane, the number 4 + j3 is located in
A. First quadrant
B. Second quadrant
C. Third quadrant
D. Fourth quadrant Ans. A - For a large value of VDS FET behaves as
A. Voltage controlled current source
B. Current controlled voltage source
C. Variable resistance
D. None of above
Ans. A
- Removing bypass capacitor across emitter leg resistor in a CE ac amplifier causes
A. Increase in voltage gain
B. Short circuit
C. Decrease in voltage gain
D. Exponential rise in current Ans. C - When a step input is given to an OP-amp integrator the output will be
A. Integral function
B. Differential function
C. Exponential function
D. Ramp function Ans. D - Hysteresis is desirable In Schmitt trigger because
A. It protects the circuit
B. It constantly magnetizes and de magnetizes it
C. Devices in the circuit should be allowed time for saturation and desaturation
D. None Ans. C - In a full wave rectifier without filter, the ripple factor is A. 0.75
B. 0.65
C. 0.482
D. 3.14
Ans. C - Minimum number of flip flops required to construct mod75 counter is
A. 7
B. 9
C. 4
D. 1 Ans. A - In a clamping circuit, the peak-to-peak voltage of the waveform being clamped is
A. Independent of the input voltage
B. Not affected by the clamping
C. Depends on the input voltage
D. All of above Ans. B - A Zener diode has a sharp breakdown
A. At low reverse voltage
B. In Forward biased state
C. In Reverse biased state
D. Never breaks down Ans. A - N channel FETs are superior to P channel because
A. Of greater concentrations of impurity
B. Mobility of electrons is greater than holes
C. Low breakdown voltage
D. Higher stability Ans. B - Negative feedback in an amplifier
A. Increases the voltage gain
B. Reduces the voltage gain
C. Does not affect the gain of amplifier
D. None of above Ans. B - For generating 1 kHz signal most suitable circuit is
A. Crystal oscillator
B. Wheatstone bridge
C. Wien Bridge Oscillator
D. Both A & C Ans. C - The main feature or prominent property of the crystal oscillator
A. Economy
B. Reliability
C. Stability
D. High frequency Ans. C - Primary of a machine Is stationary while secondary is rotating. This rotating transformer Is known as
A. Conduction motor 0.
B. Current transformer
C. Potential transformer
D. Induction motor Ans. D - For rectification, which of the following Is used?
A. Capacitors
B. Resistors
C. Diodes
D. Inductors Ans. C - Conduction angle in amplifier in class A amplifiers is
A. 180
B. 90
C. 270
D. 360
Ans. D - In amplifiers, the common mode rejection ratio (CMRR) should be
A. High (in ideal differential amplifier CMRR Is Infinity)
B. low
C. Keeps modulating between high and low
D. None or above Ans. A - A transformer with a winding ratio of 20:1 means
A. For every 20 turns of primary, there shall be one secondary turn
B. there are 20 turns on primary and 1 turn on secondary Ans. A - Power ‘P’ Is required to be transmitted by overhead lines over the length ‘L’ꞏ For the same power loss and the same voltage between conductor and earth, the least conductor material Is required In
A. 3 wire AC system
B. 2 wire DC system
C. 4 wire AC system
D. 3 wire DC system Ans. B - A 100V bulb has a resistance of 500 ohm. The number of hours it can work for every KWH of energy consumed will be
A. 10 hours
B. 35 hours
C. 55 hours
D. 50 hours Ans. D - If the poles are in the left half of s-plane then the system Is
A. Marginally stable
B. Unstable
C. Stable
D. Critically stable Ans. C - In which circuit, current leads the voltage by 90
A. Inductive
B. Resistive
C. Capacitive
D. None Ans. C - The efficiency of a transformer will be maximum when
A. Power factor Is closer to unity
B. When it is fully loaded
C. Copper losses equal to the iron losses
D. When it is loaded at half of its capacity
Ans. C
- The instrument which senses the fault and initiates the trip
A. Fuse
B. Protective relays
C. Circuit breaker
D. Barriers Ans. B - The storage of electric charge is possible in and it is charged and discharged continuously.
A. Lelanche cells
B. Edison cells
C. Lead acid battery
D. Nickel chromium battery Ans. C - Which type of instrument cannot be used for both AC and DC?
A. Dynamometer type
B. Electrostatic type
C. Induction type
D. None of these Ans. C - U235 is an isotope of Uranium making up about % of natural uranium.
A. 0.7%
B. 0.9%.
C. 0.10%
D. 0.5%
Ans. A - Which of the following is used as a moderator in nuclear reactor?
A. Graphite
B. Boron
C. Uranium
D. Hydrogen Ans. A - Occurrence of electric potential (usually less than 10 V) between two isolated objects that Ideally should not have any voltage difference between them is due to
A. Stray voltage
B. Dim voltage
C. Tame voltage
D. Ground voltage Ans. A - PMMC (Permanent Magnet Moving Coil) instruments have following features.
A. low hysteresis loss
B. Uniform scale
C. Reduced Eddy current
D. Low power consumption
E. All of above Ans. E
- Common base amplifier when compared to FET is represented as
A. Common gate
B. Common drain
C. Common source
D. None Ans. A - In electrodynamometer type wattmeter
A. Current coil is fixed
B. Pressure coil is fixed
C. Both are fixed
D. Both are moving Ans. A - A Hall’s effect sensor can be used for measuring
A. Pressure
B. Magnetic flux
C. Relative humidity
D. Current Ans. B - In an Oscilloscope, time base is generated by
A. Horizontal amplifier
B. Vertical amplifier
C. Sweep generator
D. Signal generator Ans. C - Each stage of a four-stage amplifier has a voltage gain of 12. The overall voltage gain is
A. 12
B. 34
C. 20736
D. None Ans. C - Seismic transducer is used for measuring
A. Linear velocity
B. Angular velocity
C. Acceleration
D. Pressure Ans. C - Spectrum analyzer graphically presents energy distribution of a signal as function of
A. frequency
B. Phase
C. Amplitude
D. None Ans. A
- Signal generators generate
A. Signals of varying amplitude and varying frequency
B. Repeating and non-repeating electronic signals
C. Signals of constant amplitude and constant frequency
D. None of above Ans. B - A triangular wave shape is obtained by
A. Integrating sine wave
B. Integrating rectangular waves
C. Integrating square wave
D. All of above Ans. C - wave analyzer is an instrument to measure relative amplitude of single frequency component in a
A. Complex waveform
B. Sinusoidal waveforms
C. Both A& B
D. None of above Ans. A - For an OP-AMP with negative feedback the output is
A. Equal to the input
B. Increased
C. Feedback to the inverting input
D. Feedback to the non-inverting Input Ans. C - In an operational amplifier the common mode gain is
A. Zero
B. Infinity
C. Very low
D. Very high Ans. A - An electronic oscillator is
A. Just like an alternator
B. Nothing but an amplifier
C. An amplifier with feedback
D. A converter of ac to de energy Ans. C - In RC phase shift oscillator circuit
A. There ls no need for feedback signal
B. Pure sine wave output is Possible
C. feedback factor is less than unity
D. None of above Ans. B
- Closed loop gain of a feedback amplifier is the gain obtained when
A. Its output terminals are closed
B. Negative feedback is applied
C. Feedback loop is closed
D. Feedback factor exceeds unity Ans. C
Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 4(301-400)