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
- Transmission lines are considered to be kV and above.
A. 110kv
B. 140kv
C. 130kv
D. 150kv Ans. A - The product of V-rms and 1-rms
A. Apparent power
B. Real power
C. Virtual power
D. Reactive power Ans. A
- State variable analysis is used for the modelling of type of systems.
A. Linear
B. Non-linear
C. Time variant
D. Time invariant
E. All of above Ans. E - Aero derivative turbines do not have
A. Stator
B. Compressor
C. Fuel Intake system
D. Fan Ans. D - Commercial digital/analog convertor modules are available with precision ranging from 6 bit to
A. 10
B. 12
C. 32
D. 18 Ans. D - In superposition theorem, all voltage Sources are replaced by
A. Open circuit ꞏ
B. Closed circuit
C. Short Circuit
D. Open circuit with parallel branch Ans. C - The principle of can be used to analyze fault in power system network.
A. Thevenin
B. Norton
C. Jordon
D. Superposition Ans. D - In submarine power system, power Is transmitted through cables.
A. High voltage direct current
B. Low voltage direct current
C. Under current
D. Under ampere Ans. A - RC snubber circuit is used to limit the rate of In off state.
A. Rise of current in SCR
B. Rise of voltage in SCR
C. Conduction period
D. All of above Ans. B
- Which system Is used for dc-to-dc high voltage gain?
A. Solar cell energy conversion system
B. Battery backup system
C. Fuel cell energy conversion system ꞏ
D. High intensity discharge lamp ballasts for automobile headlamps
E. All of the above Ans. E - UJT has same characteristics like
A. CE
B. BJT
C. FET
D. Diodes Ans. C - Rechargeable batteries or Pbs batteries are of type.
A. Primary batteries
B. Secondary batteries
C. Electrochemical batteries
D. None Ans. B - How ls load modeled in load flow analysis?
A. Constant power
B. Constant impedance
C. Constant load
D. Variable load Ans. A - Superposition theorem is applicable to
A. linear system
B. Linear time variant
C. Linear and non-linear
D. Linear time invariant Ans. A - Four wires are available in system
A. Star
B. Delta
C. Both A and B
D. Interconnected Ans. A - Active devices
A. Supply energy
B. Absorb energy
C. Convert energy from one form to another
D. Supply and absorb energy
E. Supply energy and convert one form to another Ans. E
- Over Current protection for motor i’s provided by
A. Kit kat fuses
B. Overcurrent Relay
C. Cartage fuses
D. None Ans B - Inductance can be measured by
A. Wien’s bridge
B. Anderson bridge
C. Shearing bridge
D. Maxwell bridge Ans D - For a fixed number of poles and armature conductors winding will give high emf
A. Lap winding
B. Wave winding
C. Copper winding Ans. B - Maxwell loop current method of solving electrical network uses
A. Branch currents
B. Kirchhoff’s voltage law
C. Is confined to single loop circuit Ans. B - Which of the following is not the type of transformer?
A. Resonant transformer
B. Cast Iron transformer Ans. B - Which of the prime movers Is least efficient?
A. Gas turbine
B. Petrol engine
C. Diesel engine
D. Steam engine Ans. D - When electromagnetic waves collide with hurdles their frequencies
A. Increase
B. Decrease
C. Remains same
D. Bounce back Ans. C - In 3-phase 4-wire system, how many voltages. are available?
A. Two
B. Three
C. Four Ans. A
- meter is used a null detector In Wheatstone bridge
A. Ammeter
B. Voltmeter
C. Galvanometer
D. Wattmeter Ans. C - If “Rt” is the resistance of a coil of copper at t° C and RT Is the resistance at To C and also the resistance temperature coefficient of copper per degree centigrade at 0°C is 1/234.45, then Rt/RT
A. (1 + t) / (l + T)
B. (1+ 234.45t) / (1+234.45 T)
C. (234.45 + t) / (234.45 + T)
D. (234.45 + t2) / (234.45 + T2)
Ans. C - The wavelength of an electromagnetic wave after reflection at an angle on a surface
A. Increases in the actual direction of propagation
B. Decreases In the actual direction of propagation
C. Remains the same as the wavelength perpendicular to the surface
D. Remains the same as in free space Ans. A - Δ x H=J + D is
A. Maxwell equation
B. Continuity
C. Laplace equation
D. Poisson equation Ans. A - The channel of a JFET Is between the
A. Gate and drain
B. Drain and source
C. Gate and source
D. Input arid output Ans. B - LTI system can be completely characterized by
A. Impulse response
B. Step input
C. Output
D. Step response Ans. A - If a signal having different frequency and different sampling frequency are time division multiplexes then it is called
A. Pulse stuffing
B. Synchronous multiplexing
C. Asynchronous multiplexing
D. FDMA Ans. A
- We build control systems for
A. Remote control
B. Convenience of Input form
C. Power amplification
D. Compensation for disturbance
E. All of the above Ans. E - Natural frequency of a system gives
A. Nature of transient
B. Overshoot
C. Oscillation
D. Speed of response Ans. D - Hay bridge is used for the measurement of
A. Inductance
B. Resistance
C. Capacitance
D. None of these Ans. A - _____bridge is used for the measurement of resistance.
A. Shearing bridge
B. Hay bridge
C. Wheatstone bridge
D. Maxwell bridge Ans. C - In an LTI system, if all the poles and zeros are inside the unit circle then
A. Its inverse does not exist
B. The system is causal and stable
C. The Inverse of system ls causal and stable
D. Both system and its inverse are causal and stable Ans. D - Under-damped systems have
A. Damping ratio > 1
B. 0 < damping ratio < 1
C. Damping ratio = 1
D. Damping ratio = 0 Ans. B - An alternator is operating on unity PF load, then
A. Armature reaction will be cross magnetizing
B. Armature reaction will be de-magnetizing
C. Armature reaction will be magnetizing
D. None of the above Ans. A
- ROC converges if poles and Zeroes lies inside
A. Origin
B. Z=l
C. Poles
D. Zeros Ans. B - ____is the fastest possible response without the overshoot
A. Under damped
B. Over damped
C. Critically damped
D. General response Ans. C - Which oscillator is the most stable oscillator?
A. Crystal
B. Wien bridge
C. Colpitts
D. Hartley Ans. A - Fourier series representation of continuous signal requires number of harmonically complex components.
A. N
B. 2pi/ N
C. n + N
D. 1
E. Infinite Ans. E - Any constant of time domain is an impulse in frequency domain with
A. Infinite height, infinite width, infinite area ꞏ
B. Infinite height, infinite width, zero area
C. Infinite height, zero width, zero area
D. Infinite height, zero width, unit area Ans. D - Which statement is true about continuous and discrete LTI system?
A. Convolution sum Is approximation to convolution integral
B. Convolution integral ls approximation to convolution sum
C. Convolution sum and integral are explicit realization
D. All Ans. C - Which of the following has super linear rate of convergence?
A. Bisection method
B. Newton Raphson method ꞏ
C. Secant method
D. False position method Ans. C
- The modulation technique in which carrier is switched between two different carrier levels 0 &1 is called
A. Amplitude shift keying
B. On off keying
C. Frequency shift keying
D. Phase shift keying Ans. B - LTI system is stable when
A. 2ero ls Inside a unit circle
B. Poles are Inside a unit circle
C. Zero at origin
D. Poles at origin ꞏ
Ans. B - Which of the following converts thermal energy to kinetic energy?
A. Thermocouple
B. Fuel cell
C. Rocket
D. Storage battery Ans. C - For constant voltage transmission, voltage drop is compensated by installing
A. Synchronous motors
B. Inductors
C. Capacitors
D. All of above Ans. A - Which of the following voltage is usually not the generating voltage?
A. 6.66kv
B. 9.9kv
C. 11kv
D. 13kv Ans. B - Boosters are basically
A. inductors
B. Capacitors
C. Transformers
D. Synchronous motors Ans. C - Difference between D-MOSFET and JFET is the absence of
A. P-N Junction
B. Drain
C. Gate
D. Source Ans. A
- FET is beneficial due to
A. Low noise
B. High power gain
C. Small size
D. All Ans. D - Vce (voltage between collector and emitter) of a transistor is very important in checking whether transistor is
A. Working in saturation
B. Working in cut off
C. Defective
D. All Ans. D - FIR filter can be designed to achieve
A. Linear phase
B. Inverting phase
C. Non-inverting phase
D. Both A & B Ans. A - In 8051 the contents of the Instruction register are split Into
A. 2 nibbles
B. 3 nibbles
C. 4 nibbles
D. 5 nibbles Ans. A - One of the properties of FIR filters Is that Is not required for FIR filters.
A. Input
B. Transfer function
C. Feedback
D. Output Ans. C - Optical power cable depends on associated with optical fiber receiver.
A. Quantum
B. Dark current
C. Thermal
D. All Ans. D - The parameter hfe of a transistor corresponds to
A. Beta dc
B. Beta ac
C. Re’
D. Rc’ Ans. B - Oscillator whose frequency can be changed by a DC control voltage is
A. Triangular wave oscillator
B. Wien-bridge oscillator
C. Crystal oscillator
D. Voltage controlled oscillator Ans. D - DC operating point of an amplifier specified by voltage and current value is called ꞏ
A. Gain
B. Q point
C. load line
D. None of above Ans. B - In RLC circuits, at low frequency, Z is larger due to
A. XC is larger ꞏ
B. XL is larger
C. XC is smaller
D. None Ans. A - ____is the part of instruction which tells. the computer which operation to perform next.
A. OP code
B. On code
C. RAM
D. ROM Ans. A - In 8085______ls the part of a control unit.
A. ROM
B. RAM
C. Instruction registers
D. OP code Ans. C - JFET has main drawback of
A. Having low input impedance
B. Noise distortion
C. Having small gain-bandwidth product
D. None Ans. C - In order to have a lower cost of electrical energy generation
A. The load factor and diversity factor should be low
B. T1ie load factor and diversity factor should be high
C. The load factor should be low and diversity factor should be high
D. The load factor should be high and diversity factor should be low Ans. B
- When the current In the light bulb drops by 2%, its power decreases by
A. 4 %
B. 2 %
C. 8 %
D. 16 %
Ans. A - What is common mode rejection ratio CMRS?
A. It Is ratio of differential mode gain to common mode gain
B. It Is the ratio of common mode gain to differential mode gain
C. It is the product of common mode pin and differential mode gain
D. None of these ‘ Ana. A - Resolution of ADC is defined as the no of bits In
A. Output
B. Input
C. I/O
D. None Ana. A - The most common method for measurement of low resistance Is
A. Wheatstone bridge method
B. Potentiometer method
C. Kelvin bridge method Ans. C - The shunt winding of a motor has a resistance of 85 ohm at 22°C. When the motor runs at full load, its resistance. increases to 100 ohms. The resistance temperature coefficient of winding per 0°C is 0.004. The rise.in temperature of the winding will be nearly
Ans. 70o C
- If the height of transmission tower is Increased, which of the following parameters are likely to change?
A. capacitance
B. Inductance Ans. A - If ROC (Region of convergence) does not include unit circle then
A. Fourier transforme converges
B. Z-transforme converges
C. Harley transforme converges
D. Chirplet transforme converges
Ans. B
- In MSI (Medium Scale Integration) technique; the number of transistors on the single IC package can be fabricated are
Ans. 10 to 100
- In LSI (Large Scale Integration) technique, the number of transistors, which can be fabricated on the single IC are
Ans. 100 to 1000
***For small scale integration 0 to 10 transistors
- TTL (Transistor Transistor Logic) of chip Integration uses
A. Bipolar Junction transistor
B. Field effect
C. Complementary symmetry metal oxide
D. None Ans. A - For getting the sampled signal without any distortion, Nyquist criteria, the minimum sampling period must be according to
A. Double the max period
B. Equal to the max period
C. Greater than the max period
D. Half the max period Ans. D - How is thyristor turned off?
A. By forced commutation
B. Forward biasing
C. Reverse gating
D. None Ans. A - For a silicon diode. the value of the forward bias voltage is A. 0.1
B. 0.3
C. 0.7
D. Depends on the concentration of majority carriers Ans. C - In high frequency applications we use
A. Pulse transformer
B. Air core transformersꞏ ꞏ. ꞏ
C. Ferrite core transformers
D. None Ans. B - If there are less than 4 electrons in the valence shell, then the element is generally, a
A. Conductor
B. Insulator B
C. Semiconductor
D. none of these Ans. A - Which is not a type of substation?
A. Line
B. Collector
C. Converter
D. Switching Ans. A - What is the basic principle behind motor operation?
A. Electromagnetism
B. Electrostatic induction
C. Magnetism
D. None Ans. A - Most squirrel cage rotors are made by die casting of conductor bars.
A. Copper
B. Aluminum
C. Zinc
D. Silver Ans. B - The _ of measurement is a measure of change in the instrument output, which occurs when the quantity being measured changes by a given amount. ꞏ
A. Sensitivity
B. Accuracy
C. Threshold
D. None Ans. A. - ______transforms voltage from high to low and reverse and perform any of several other important functions. ꞏ
A. Substation
B. Grid
C. Switchyard
D. None Ans. A - The input for a distribution substation is typically at least transmission lines or sub- transmission lines.
A. Two
B. three
C. Four
D. None Ans. A
- When a small resistance or impedence is Inserted between two points of different potentials, accidentally or intentionally. It is called
A. Short circuit
B. Open
C. Close circuit
D. None Ans. A - Hollow conductors are use in transmission line to
A. To reduce corona
B. To reduce weight of the copper
C. Improve stability
D. Increase power transmission capacity Ans. A - Shunt reactors are connected with transmission lines for
A. Limiting fault current
B. Limiting fault voltage
C. Absorbing reactive power
D. Absorbing High voltage surges Ans. C - In a DC machine, what is the angle between rotor and stator fields
A. 45
B. 90
C. 120
D. 180
Ans. B - Which of the following motor has the highest torque?
A. DC series motor
B. AC series motor
C. Induction motor
D. Synchronous motor Ans. A - Motor that should not be used with load removed is
A. Series motor
B. Shunt motor
C. C Both
D. None Ans. A - The process of conversion of AC into DC is called
A. Magnification
B. Amplification
C. Purification
D. Rectification Ans. D
- The region of operation of transistors is_____ if emitter junction is forward
biased and collector junction is reverse biased.
A. Active
B. Saturation ꞏ
C. Cutoff
D. Inverted Ans. A - When no signal input, a bipolar transistor would have least lc where
A. Emitter base junction is reverse biased
B. Emitter grounded
C. Emitter base Junction forward biased
D. Emitter base current high Ans. A - An N-type and P-type semiconductor can be obtained by doping silicon with ꞏ.
A. Sodium and magnesium respectively
B. Phosphorus and boron respectively
C. Indium and sodium respectively
D. Boron and arsenic respectively Ans. B - The form factor in reference to alternating current waveform represents the ratio of
A. The average value to RMS value
B. The peak value to RMS value
C. The RMS value to average value
D. The RMS value to peak value Ans. C - Power factor of-magnetizing component of a transformer is
A. Zero
B. Unity
C. 0.8 lagging
D. Always leading Ans. A - If the horizontal and vertical components of Earth’s magnetic field are equal then angle of dip ls
A. 45•
B. 90•
C. 60°
D. 30•
Ans. A
Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 3(201-300)