Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 6(501-600)

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Smart series MCQs set 6 for all electrical engineering tests for post of Junior engineer/SDO in WAPDA ,GEPCO jobs NTS, NTDC,MEPCO,IESCO,PESCO and all DESCOS

  1. Curl of vector is cross product of Δ with that vector
    A. Two dimensional
    B. Three dimensional
    C. One dimensional
    D. None Ans. B
  2. The current is flowing in to positive terminal of the battery, the power is being
    A. Absorbed

B. Discharged
C. Unaltered
D. None of above Ans. A

  1. Difference between synchronous speed and is called slip
    A. Actual speed
    B. Asynchronous speed
    C. None of above Ans. A
  2. EMF is Integral of non-conservational electric field generated by power source.
    A. Line
    B. Constant
    C. Surface
    D. None of above Ans. A
  3. Electronic circuits with high gain and phase shift condition produce
    A. Oscillations
    B. Damping
    C. Resonance
    D. Fluctuations Ans. A
  4. Squirrel cage rotor with number of bars prevent current induced from imposing back to supply
    A. Even
    B. Odd
    C. Prime O
    D. Natural Ans. C
  5. The definite integral of dy / dx = cos x is
    A. Sin X
    B. Tan X
    C. -Sin X
    D. None of these Ans. A
  6. The disadvantage of a half wave rectifier is that_
    A. Components are expensive
    B. Diode must have a high-power rating
    C. Output is difficult to filter
    D. None Ans. C
  7. Noise in resistance depends upon
    A. Temperature
    B. Sampling rate

C. Material
D. All of above Ans A

  1. In a parallel resonance circuit, at resonance
    A. Impedance is zero
    B. Current is maximum
    C. Voltage is maximum
    D. impedance is minimum Ans. C
  2. What Is meant by Admittance?
    A. Measure of how a circuit or device will oppose the flow of current
    B. Measure of how easily, circuit or device will allow the flow of current
    C. Measure of how easily, circuit or device will divert the flow of current
    D. None of the above Ans. B
  3. Force on one meter length of conductor in magnetic field created by a current of 1 ampere Is
    A. EMF
    B. Voltage
    C. Electric intensity
    D. Magnetic Induction Ans. D
  4. In right hand rule thumb points in the direction of current and finger curl in the direction of
    A. Electric field
    B. Electric force
    C. Magnetic field
    D. None of above Ans. C
  5. Radius of curvature of the path of a charged particle in a uniform magnetic field is directly proportional to
    A. Flux density of field
    B. Particle’s energy
    C. Particle’s momentum
    D. Particle’s charge Ans. C
  6. effect determines the sign of charge.
    A. Thomson
    B. Seeback
    C. Hall
    D. Petlier Ans. C
  7. Time constant of a series R-L circuit equals
    A. L/R
    B. C/R

C. R/L
D. All Ans. A

  1. Amperes law is concerned with
    A. A unit magnetic pole
    B. Electrochemical equivalent
    C. Force on wire carrying current in a magnetic field
    D. RMS value Ans C
  2. Resistance, Capacitance and inductance are
    A. Active
    B. Redundant.
    C. Passive elements
    D. None of above Ans.
  3. Magnets were first used by
    A. Indians
    B. Europeans
    C. Chinese
    D. Japanese Ans, C
  4. A bridge used for the measurement of capacitance or dielectric loss of an Insulator
    A. Shearing bridge
    B. Hay bridge
    C. Wheatstone bridge
    D. None Ans. A
  5. Long wire wound tightly on a cylinder core Is called
    A. Toroid
    B. Solenoid
    C. Cable
    D. Conductor Ans. B
  6. Lenz’s law Is law of conservation of
    A. Momentum
    B. Charge
    C. EMF
    D. Energy Ans. A
  7. A material having strong magnetic properties is called
    A. Paramagnetic
    B. Ferromagnetic

C. Diamagnetic
D. None of above Ans. B

  1. For a fuse rating of. 2.5 KW and 220V Volt microwave the rating of the current is
    A. 5A
    B. 10 A
    C. 12A Ans. C
  2. The brush voltage drops in DC motor is usually of the order of
    A. 4
    B. 6
    C. 11
    D. 2 Ans. D
  3. What will happen if relative speed b/w rotating flux of the stator rotor of induction motor Is zero
    A. Torque produced will be very large
    B. Rotor will not run
    C. Rotor runs at high speed
    D. Slip of motor Is 5% Ans. B
  4. If the oscillations per minute of a rotor are 120 with a stator frequency of 50 Hz, slip will be A. 10%
    B. 12%
    C. 4%
    D. 8% Ans. C
  5. The power scale, of circle diagram of an induction motor can be found from
    A. Stator resistance test
    B. No load test only
    C. Short circuit test only
    D. None of above Ans. c
  6. Variation in supply mains, frequency is compensated by In industrial motors
    A. Overcurrent relays
    B. VFD
    C. Opto-electronic devices
    D. Centre tapped transformers Ans. B
  7. Critical resistance of a DC generator Varies with
    A. 1/N2
    B. 1/N
    C. N2

D. N Ans. D

  1. Which statement is valid for a single-phase capacitor start motor in steady state?
    A. Forward flux by rotor current is equal to backward flux by rotor
    B. Net forward flux is equal to net backward flax by rotor current
    C. Net forward flux is less than net backward flux by rotor current
    D. None of above Ans. B
  2. Hopkinson test is conducted at
    A. Full load
    B. Low load
    C. Part load
    D. No load Ans. A
  3. The back EMF of a DC motor depends on
    A. Field flux
    B. Shape of conductors
    C. Type of slip rings
    D. Brush material Ans. A
  4. Equalizer connections are required when paralleling two
    A. Bipolar generators
    B. Series generators
    C. shunt generators
    D. Compound generator Ans D
  5. Highest losses in a DC motor are
    A. Copper losses
    B. Core losses
    C. Mechanical losses
    D. None of the above Ans. A
  6. A DC motor can easily be identified by
    A. Yoke
    B. Commutator
    C. Size of conductor
    D. Winding Ans. D
  7. The torque speed characteristics of a DC motor
    A. Parabola
    B. Linearly rising
    C. Rectangular hyperbola
    D. Linearly declining

Ans. Cꞏ

  1. Usually very wide and sensitive speed control method is used for
    A. Reciprocating pumps
    B. Colliery winders
    C. Centrifugal bellows
    D. Lathe machine Ans. B
  2. A large size alternator is protected against over loads by providing
    A. Overcurrent relays
    B. Thermal relays
    C. A combination of A & B
    D. Temperature sensitive relays Ans. D
  3. Which of the following test can be used to determine the efficiency of two identical transformer?
    A. open circuit test
    B. short circuit test
    C. Type tests
    D. back-to-back test Ans. D
  4. Ratio error of a current transformer due to the presence of
    A. Exciting current
    B. Stray magnetism
    C. corona effects
    D. Lagging power factor Ans. A
  5. Device which compares difference between the voltages and sends Signals
    A. Oscillator
    B. Voltage comparator
    C. None
    D. controller Ans. B
  6. In JFET, shunt sampling gate has
    A. Voltage
    B. current
    C. AC
    D. DC Ans. B
  7. sampling gate is
    A. OR
    B. NAND
    C. linear
    D. Random

Ans. C

  1. circuits always have memory elements
    A. Combinational
    B. Sequential
    C. Elemental
    D. None of these Ans. B
  2. Early effect of BJT refers to
    A. Avalanche breakdown
    B. Thermal runaway
    C. Base narrowing
    D. Zener breakdown Ans. C
  3. Voltage gain of common collector is
    A. Equal to 1
    B. Greater than 10
    C. Greater than 1
    D. Less than 1 Ans. D
  4. In transistor circuit capacitor Is used
    A. Mica
    B. Air
    C. Paper
    D. Electrolyte Ans. D
  5. The output Impedance of a CB transistor Is
    A. High
    B. Zero
    C. Low
    D. Very low Ans. A
  6. The Input Impedance of a CB transistor is
    A. High
    B. Zero
    C. Low
    D. Very low Ans. C
  7. In an ideal op amp if a different signal is applied at both the ends the output will be
    A. Zero
    B. Infinite
    C. Input 2 – input 1
    D. None Ans. B
  8. If same signal of 0.4 V is applied on both ends of the op amp with 100 dB gain. Theꞏ output will
    A. Zero
    B. Infinite
    C. 1
    D. None of above Ans. A
  9. Multiplexer converts ꞏ
    A. Parallel data into parallel data
    B. serial data into parallel data
    C. Parallel data into serial data
    D. Serial data into serial data Ans C
  10. ASCII (American standard code for information interchange) is bits code
    A. 5
    B. 7
    C. 12
    D. 18 Ans. B
  11. Decoders convert binary Input to output.
    A. Decimal
    B. Hexadecimal
    C. octal
    D. Binary Ans. A
  12. In a radio receiver
    A. All stages contribute to equally to noise
    B. RF stage has no effect on S/N ratio
    C. Mixer stage contributes most of the noise generated u
    D. RF stage has effect on S/N ratio Ans C
  13. A radio receiver has of amplification
    A. Double stage
    B. Single stage
    C. Three stages
    D. More than 3 stages Ans. D
  14. Hot wire anemometers are used to measure
    A. velocity of air stream
    B. Pressure
    C. Leakage reactance Ans. A
  15. The letter DPDT is for
    A. Switch
    B. Conductor
    C. Thick wire
    D. Fuse Ans. A
  16. Due to burning of 1 Kg of pure carbon with a ‘minimum quantity of air required, the percentage of carbon dioxide in the exhaust gas would be
    A. 10%
    B. 19%
    C. 29%
    D. 39%
    Ans. C
  17. A graphical representation between discharge and time is known as
    A. Monograph
    B. Hectography
    C. Hectograph
    D. Hydrograph Ans D
  18. In an ideal diesel cycle, the working substance is
    A. Air
    B. Diesel
    C. Mixture of air and diesel
    D. Any combustible material Ans. A
  19. Which of the following is generally not a constitute of coal?
    A. Sulphur
    B. Moisture
    C. Chromium
    D. Hydrogen Ans. C
  20. coal rank classifies coal according to its
    A. carbon percentage
    B. Ash content
    C. Degree of metamorphism
    D. Density Ans. C
  21. Power plants using coal work closely on which of the following cycle
    A. Otto cycle
    B. Binary vapor cycle
    C. Brayton cycle
    D. Rankine cycle Ans. D
  22. The air standard efficiency of a diesel engine depends on
    A. Compression ratio
    B. Speed
    C. Torque
    D. All of above Ans A
  23. Coking is
    A. Formation of lumps or masses of coke in boiler surfaces at high temperatures
    B. Heating of coal in absence of air, driving out CO2 and leaving in the residue and carbon
    Ans. B
  24. Deuterium oxide in nuclear reactors
    A. Moderator
    B. Fuel
    C. Shield Ans. A
  25. The output of a solar cell of the order of
    A. 0.1W
    B. 0.5W
    C. 1W Ans. C
  26. As compared to steam at enter to the turbine, which of the following will larger at exit
    A. flow rate
    B. specific enthalpy
    C. specific volume
    D. pressure Ans. C
  27. The model of transmission line in which full charging current flows over half of the line
    A. Nominal T
    B. short line
    C. Nominal N
    D. Equivalent N Ans. A
  28. which of the following is called “certain length of actual transmission line”?
    A. Electronic delay line
    B. Distribution delay line
    C. Electromagnetic delay line
    D. Magnetic delay line Ans. B
  29. Transient state stability is generally improved by
    A. Using high speed governors on machines
    B. Using low inertia machines

C. Dispensing with neutral grounding
D. Any of above Ans. A

  1. The surge resistance of transmission is about
    A. 50 ohms
    B. 400 ohms
    C. 800 ohms Ans B
  2. In high voltage transmission line, the top most conductor is
    A. R-phase conductor
    B. Y-phase conductor
    C. B-phase conductor
    D. Earth conductor Ans D
  3. Skin effect is proportional to
    A. Diameter of conductor
    B. (Diameter of conductor)2 Ans. B
  4. Shunt capacitance is usually neglected in the analysis of
    A. Short transmission lines
    B. Medium transmission
    C. Long transmission lines
    D. Medium as well as long transmission lines Ans. A
  5. In order to reduce skin effect at UHF
    A. Conductors are painted
    B. Conductors are anodized
    C. Copper tubes with silver plating are used
    D. Copper rods with silver plating are used Ans. C
  6. Transmission lines linkꞏ
    A. Service point to consumer premises
    B. Distribution transformer to consumer premise
    C. Receiving end ꞏstation to distribution
    D. Generating station to receiving end station Ans. D
  7. The flow chart of a thermal power plant consists of main circuits.
    A. Four
    B. Five
    C. Six
    D. Seven Ans. A
  8. In the furnace is arranged as a horizontal cylinder.
    A. horizontal boiler
    B. Vertical boiler
    C. Cylindrical boiler
    D. Cyclone fired boiler Ans. D
  9. Fossil fuel power plants often have a section in the steam generating furnace.
    A. Heat recovery
    B. Heat exchanger
    C. Super heater
    D. None of above Ans C
  10. Overload protection requires which simply measure the current in circuit and is used with protection device for measuring.
    A. power transformer
    B. auto transformer
    C. current transformer
    D. None Ans C
  11. measure both voltage and current at the relaying point
    A. Earth fault protection
    B. Differential protection
    C. Distance protection ꞏ
    D. None E.
    Ans C
  12. Protective device is the process of determining the “best fit” timing of current interruption when fault occurs
    A. Diagnosis
    B. Coordination
    C. Calibration
    D. All of above Ans. B
  13. In one or two phases become connected to earth via low Impedance path, their magnitudes will increase dramatically as current will imbalance.
    A. Earth fault
    B. Phase to phase fault
    C. Symmetrical fault
    D. None Ans. A
  14. is used because they offer precise control of voltage, frequency, VARS and Watts.
    A. Induction generator
    B. Synchronous generator

C. DC generator
D. AC-generator Ans B

  1. In process control system, there are three main terms or factors manipulated variable, and uncontrolled variables.
    A. Controlled variable
    B. Disturbance
    C. Both A& B
    D. None of above Ans B
  2. Process control consists of four essential elements such as process, measurement, and control
    A. Analysis
    B. Evaluation
    C. Quality
    D. None of above Ans B
  3. provide a conductive path for DC for rotating field winding.
    A. Termina1 ends
    B. Collector ring
    C. commutator
    D. None of above Ans B
  4. Internal parts of a motor are protected from environmental elements by
    A. Frame
    B. Enclosure
    C. Housing
    D. Capsule
    E. casing Ans. B
  5. exciter gets field power from generator output voltage
    A. Series type
    B. Shunt type
    C. Brushless type
    D. Brush type
    E. Console type Ans. B
  6. which feeds its own field current from its output
    A. Self-excited generator
    B. Separately excited generator Ans. B

Originally, it’s A but NTS marks B

  1. Modern voltage regulators are designed to maintain the generator line voltage within better than of nominal for wide variations of machine load.
    A. ±1%
    B. 5%
    C. ±3%
    D. ±7%
    Ans A
  2. Sinusoidal voltage and current at constant frequency are characterized by 2 parameters; A maximum value and
    A. Phase angle
    B. Value of load angle
    C. R value
    D. Load angle Ans. A
  3. Reactive power that can be generated at low load is determined by
    A. Field current heating limit
    B. Field current cooling limit
    C. Field current overheating limit
    D. None of above Ans. A
  4. Power system is a word used in connection with the power system denoting a condition wherein, the various alternators in the system remain in synchronism with each other.
    A. Range
    B. Loop
    C. Gain
    D. Conservation
    E. Stability Ans. E
  5. Transformers are used for voltage of low values and transformers for high voltages.
    A. Electronic; Power
    B. Power; Electronic
    C. Neither A or B
    D. Current; Instrument Ans. A
  6. Which of following circuits are used to measure performance of transformer?
    A. Equivalent circuit
    B. Power circuit
    C. Electronic circuit
    D. Both A& B Ans. A
  7. Which transformer splits secondary voltage into two equal voltages?
    A. Power transformer

B. Centre tapped transformer
C. Current transformer
D. Step up transformer Ans. B

Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 7(601-700)

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