Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 11(1000-1100)

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Smart series MCQs set 11 for all electrical engineering tests for post of Junior engineer/SDO in WAPDA ,GEPCO jobs NTS, NTDC,MEPCO,IESCO,PESCO and all competitive exams.

  1. A 6 V battery is connected to a 300 cl load. Under these conditions, it is rated at 40 Ah. How long can it supply current to the load?
    A. 1 h
    B. 200 h
    C. 2,000 h

D. 10 h Ans. C

  1. A half-watt is equal to how many mill watts?
    A. 5,000 mW
    B. 5 mW
    C. 500 mW
    D. 50 mW Ans. C
  2. Three hundred joules of energy are consumed in 15 s. The power is A. 2,000 W
    B. 2 W
    C. 20 W
    D. 200 W Ans. C
  3. How much continuous current can be drawn from a 60 Ah battery for 14 h?
    A. 42.8 A
    B. 428 A
    C. 4.28 A
    D. 4.2 A Ans. C
  4. A 68-ohm resistor is connected across the terminals of a 3 V battery. The power dissipation of the resistor is
    A. 132 mW
    B. 13.2 mW
    C. 22.6 mW
    D. 226 mW Ans. A
  5. if the value of C in a series RLC circuit is decreased, the resonant frequency
    A. Is not affected
    B. Increases
    C. Is reduced to zero
    D. Decreases Ans. B
  6. The conductance of an 8 ohms resistance is
    A. 12.5 mS
    B. 8 mS
    C. 12 S
    D. 125 mS Ans. D
  7. A two-terminal variable resistor is known as a
    A. Potentiometer
    B. Thermistor
    C. Rheostat

D. Wiper Ans. C

  1. When the speed at which a conductor is moved through a magnetic field is increase, the induced voltage
    A. Increases
    B. Remains constant
    C. Decreases
    D. Reaches zero Ans. A
  2. The induced voltage across a coil with 250 turns that Is located in a magnetic field that Is changing at a rate of 8 W h/s is
    A. 1.000 V
    B. 2,000 V
    C. 31.25 V
    D. 3,125 V
    Ans. B
  3. For a given wire wound core, an increase in current through the coil
    A. Reverses the flux lines
    B. Decreases the flux density
    C. Increases the flux density
    D. causes no change in flux density Ans. C
  4. If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density
    A. Increases
    B. Decreases
    C. Remains the same
    D. Doubles Ans. B
  5. When the current through the coil of an electromagnet reverses, the
    A. direction of the magnetic field reverses
    B. direction of the magnetic field remains unchanged
    C. magnetic field expands
    D. magnetic field collapses Ans. A
  6. The unit for reluctance is
    A. Tesla
    B. At/(m*Wb)
    C. At/m
    D. Wb Ans. B
  7. What kVA rating is required for a transformer that must handle a maximum load current of 8 A with a secondary voltage of 2 kV?

A. 4 kVA
B. 0.25 kVA
C. 16 kVA
D. 8 kVA Ans. C

  1. A certain transformer has 400 turns in the primary winding and 2,000 turns in the secondary winding. The turns ratio is
    A. 0.2
    B. 0.4
    C. 5
    D. 25 Ans. C
  2. The primary winding of a transformer has 110V AC across it. What is the secondary voltage if turns ratio is 8?
    A. 8.8 V
    B. 88 V
    C. 880 V
    D. 8,800 V
    Ans. C
  3. In a certain loaded transformer, the secondary voltage is one-fourth the primary voltage. The secondary current is
    A. One-fourth the primary current
    B. Four times the primary current
    C. Equal to the primary current
    D. One-fourth the primary current and equal to the primary current Ans. B
  4. The primary winding of a power transformer should always be
    A. open
    B. shorted
    C. switched
    D. fused Ans. D
  5. In a certain transformer, input power to primary is 120W. If 8.5W are lost to winding resistance, what is the output power to the load, neglecting any other issues?
    A. 0 W
    B. 14.1W
    C. 111.5 W
    D. 1,020 W
    Ans. C
  6. The maximum output voltage of a certain low-pass filter is 15. Output voltage at the critical frequency is
    A. 0 V
    B. 15 V
    C. 10.60 V

D. 21.21 V
Ans. C

  1. Impulse testing of transformers is done to determine the ability of
    A. Bushings to withstand vibrations
    B. insulation to withstand transient voltages
    C. windings to withstand voltage fluctuations
    D. all of the above Ans. B
  2. vacuum insulation is used in all of the following EXCEPT
    A. Particle accelerators
    B. EHT of color TV
    C. Field emission tubes
    D. X-rays Ans. B
  3. All of the following dielectric materials are preferred for high frequency applications EXCEPT
    A. Polyethylene
    B. Butyl rubber
    C. Teflon
    D. Polystyrene Ans. B
  4. The output of a NAND gate when both the inputs are high is
    A. High
    B. Low
    C. High-high
    D. Low-low Ans. B
  5. A 100 W bulb is connected in series with a room heater. If now 100 W bulb is replaced by a 40 W bulb the heater output will
    A. Increase
    B. Decrease
    C. Remains same
    D. Uncertain Ans. B
  6. Kirchhoff’s Laws are applicable to circuits with
    A. Lumped parameters
    B. Passive elements
    C. Non-linear resistances
    D. All of these Ans. A
  7. Thermocouple is based on
    A. Seeback effect
    B. Thomson effect

C. Joule’s law
D. Hall’s effect Ans. A

  1. According to fuse law, the current carrying capacity varies as
    A. D
    B. D1/2
    C. D3/2
    D. 1/D Ans. C
  2. Laplace transform of a unit step function Is
    A. 1
    B. S
    C. 1/s
    D. S2 Ans. C
  3. The laplace transform of e-at Cos(wt) Is A. (s+a) / (s+a)2 + w2
    B. s / (s+a)2
    C. (S+a) / (s+a)2 – w 2
    D. S / (5+a)2
    Ans. A 2
  4. An electric circuit with 10 branches and 7 nodes will have
    A. 3 loop equations
    B. 4 loop equations
    C. 7 loop equations
    D. 10 loop equations Ans. B
  5. The surface integral of the normal component of the electric displacement D over any closed surface equals the charge enclosed by the surface. This statement is associated with
    A. Gauss’s law
    B. Kirchhoff’s law
    C. Faraday’s law
    D. Lenz’s law Ans. A
  6. A network is said to be a non-linear if it does not satisfy
    A. Homogeneity condition
    B. Superposition condition
    C. Both Homogeneity condition as well as superposition condition
    D. Homogeneity, superposition and associative condition Ans. C
  7. Instrument used for DC measurement alone is
    A. Moving iron type

B. Permanent magnet type
C. Electrodynamic type
D. Induction type Ans. B

  1. As the height of the transmission tower is increased, the line capacitance and line inductance
    and respectively.
    A. Decreases, Decreases
    B. Increases, Decreases
    C. Decreases, remains unaltered
    D. Increases, Increases Ans. C
  2. Addition of Zeros in a transfer function causes
    A. Lead compensation
    B. Lag compensation
    C. Lead lag compensation
    D. Interval compensation Ans. A
  3. The knowledge of transfer function of a system is necessary for the calculation of
    A. Output for a given input
    B. Steady state gain
    C. Order of the system
    D. Time constant
    E. All of the above Ans. E
  4. Which of the following technique is not applicable to non-linear system?
    A. Functional analysis
    B. Nyquist criterion
    C. Quasi linearization
    D. Phase plane representation Ans. B
  5. The SCR is a device.
    A. Uni-directional
    B. Bi-directional
    C. Tri-directional
    D. Two terminal Ans. A
  6. The most commonly used transistor arrangement is
    A. Common emitter
    B. Common base
    C. Common collector
    D. None of these Ans. A
  7. The shunt derived series fed feedback in an amplifier

A. Increases its output impedance
B. Decreases its output impedance
C. increases its input impedance
D. Both B and C Ans. D

  1. A pulse transformer uses a core.
    A. Copper
    B. Iron
    C. Ferrite
    D. Air Ans. C
  2. Which of the following can be generated by the use of a monostable multivibrator?
    A. Sweep
    B. Pulse
    C. Sinusoidal
    D. Any of the above Ans. A
  3. The best electronic device for fast switching is
    A. BJT
    B. Triode
    C. JFET
    D. MOSFET Ans. D
  4. The minimum value of current required to maintain conduction in an SCR is called its
    current.
    A. Commutation
    B. Holding
    C. Gate trigger
    D. Breakover Ans. B
  5. An ideal voltage amplifier should have
    A. Ri = 0, Ro = 0
    B. Ri = 0, Ro = infinity
    C. Ri = infinity Ro = 0
    D. Ri = infinity, Ro = infinity Ans. C
  6. An ideal current amplifier should have
    A. Ri = 0, Ro = 0
    B. Ri = 0, Ro = infinity
    C. Ri = infinity, Ro = 0
    D. Ri = infinity, Ro = infinity Ans. B
  7. How many flip flop circuits are needed to divide by 16?

A. Two
B. Four
C. Eight
D. Sixteen Ans. B

  1. 64 K is
    A. 6400
    B. 64000
    C. 65536
    D. 66536
    Ans. C
  2. The mnemonics used in writing a program is called
    A. Assembly language
    B. Fetch cycle
    C. Micro instruction
    D. Object program Ans. A
  3. XOR function can be realized by a minimum of
    A. 2 NAND gates
    B. 4 NAND gates
    C. 5 NAND gates
    D. 3 NAND gates Ans. C
  4. Magnetrons are commonly used as radar transmitters because
    A. High power can be generated and transmitted to aerial directly from oscillator
    B. It is easily cooled
    C. It is a cumbersome device
    D. All of the above Ans. A
  5. Which of the following is essential for fast communication?
    A. High S/N ratio
    B. High channel capacity
    C. Large bandwidth
    D. All of the above Ans. A
  6. Lissajous patterns obtained by an oscilloscope can be used to get
    A. Phase information
    B. Frequency of input signal
    C. Both frequency and phase information
    D. Voltage amplitude Ans. C
  7. An oscilloscope is generally used to measure the value of voltage
    A. DC

B. RMS AC
C. Peak to peak AC
D. Average value of AC Ans. C

  1. The inverse Fourier transforms of the function

A. Sin cot
B. Cos (01
C. Sin (t)
D. U (t) Ans. C

  1. The Fourier transform of a unit step function is given by
    A. F (j w) = j /w
    B. F (j w) = w
    C. F (jW) = 1/ jW
    D. F (j w) = 1 / w Ans. C
  2. The form factor of a 220v, 50 Hz AC waveform is A. 1.5
    B. 1.14
    C. 1.11
    D. 0.85
    Ans. C
  3. Conductors have an excess of
    A. Free electrons
    B. Electrons
    C. Protons
    D. Neutrons Ans.
  4. In superposition theorem, independent current sources are replaced with
    A. Short circuit
    B. Open circuit
    C. Close circuit
    D. Active circuit Ans. B
  5. Which wave has the highest value of form factor?
    A. Sine wave
    B. Triangular wave
    C. Square wave
    D. Half wave rectified sine wave Ans. D
  6. A functional software is managed by
    A. Computer programmer but not computer organization

B. Computer programmer and computer organization
C. Not Computer programmer, not computer organization
D. Not Computer programmer but computer organization
Ans. D

  1. Orthogonal means two lines
    A. Parallel to each other
    B. Perpendicular to each other
    C. Coplanar
    D. None of these Ans. B
  2. Accuracy of an instrument is defined as
    A. precision+ Calibration error
    B. B. Precision + sensitivity D
    C. Precision + resolutions Ans. A
  3. The bandwidth of an optical fiber can be increased by
    A. WDM
    B. TDM
    C. FDM
    D. None Ans. A
  4. If the angle between voltage and current is 90 then the power consumed is?
    A. Zero
    B. Maximum
    C. Minimum
    D. Half Ans. A
  5. What will be the output Vo?

A. 12
B. -12
C. 6
D. -6 Ans. D

  1. Fourier transform imposes parity for Fourier cosine.
    A. Even
    B. Odd
    C. Both even and odd
    D. None
    Ans. A
  2. The ideal delay system is defined by the equation Y[n) = x(n-nd), – inf <n< inf. Where nd is a fixed negative integer in above equation, then the system would
    A. Shift the input sequence to the right by nd samples to from the output
    B. Shift the input sequence to the left by nd samples to form the output
    C. The output of the system remains unchanged for positive or negative values of the nd
    D. The system will become unstable and output will remain undefined Ans. B
  3. Which term relates analog and its discrete representation?
    A. Sampling
    B. Quantization
    C. Digitization
    D. None of the above Ans. B
  4. The stability of a general dynamical system with no input can be described with stability.
    A. PID
    B. Lyapunov
    C. Haralop
    D. None Ans. B
  5. A Function is if it lies in open interval.
    A. Differentiable
    B. Dependent
    C. Independent
    D. Not differentiable Ans. A
  6. Fourier transform of discrete time system is represented as
    A. continuous frequency spectrum continuous time response
    B. discrete frequency spectrum discrete time response
    C. discrete frequency spectrum continuous time response
    D. continuous frequency spectrum discrete time response Ans. D
  7. d (function)2 / dt2 = 1 / k x d (function) / dt is known as
    A. Parabolic
    B. Elliptical equation
    C. Telegraphy
    D. Laplace equation Ans. C
  8. Following is known as

A. Gibb’s equation
B. Euler equation
C. Dirichlet equation

D. Green equation Ans. B

  1. Superposition theorem applies to a circuit which have voltage and current sources.
    A. More than one
    B. More than two
    C. More than three
    D. None Ans A
  2. Matrix has m rows and n columns the order of the product of both matrices will be
    A. M
    B. N
    C. m x n
    D. n x m Ans. C
  3. In Thevenin Theorem the equivalent resistance is connected in series with
    A. Voltage source
    B. Current source
    C. Power source
    D. None of these Ans. A
  4. Electric lines of force at right angle to its length tend to
    A. Move away from each other
    B. Cross each other
    C. Come close to each other
    D. None Ans. A
  5. Current carrying conductor at right angle to the magnetic field experiences
    A. Force
    B. Torque
    C. Momentum
    D. Acceleration Ans. A
  6. The armature reaction of an unsaturated DC machine is
    A. Non magnetizing
    B. Magnetizing
    C. Demagnetizing
    D. Cross magnetizing Ans. D
  7. The insulating properties of transformer oil are adversely affected by the presence of
    A. Oxygen
    B. Copper
    C. Ozone
    D. Moisture

Ans. D

  1. Which type of instruments can be used for the measurement of AC only?
    A. Moving iron type
    B. PMMC type
    C. Induction type
    D. None of the above Ans. C
  2. Super-heated steam is always
    A. at a temperature higher than the saturation temperature corresponding to a steam pressure
    B. at a pressure more than the boiler steam pressure
    C. separated from water particles before being supplied to turbine
    D. at a pressure less than the maximum cycle pressure Ans. A
  3. The dictates that higher efficiencies can be attained by increase in the temperature of steam.
    A. Steam efficiency
    B. Carnot efficiency
    C. Mechanical efficiency
    D. None Ans. B
  4. Which is not a part of steam turbine or coal fired power plant?
    A. Condenser
    B. Boiler
    C. Superheater
    D. Moderator Ans. D
  5. energy needs no boiler/condenser since they use natural occurring steam source.
    A. Geothermal
    B. Hydel
    C. Solar
    D. None of the above Ans. A
  6. Performance and design criteria for system protection devices include , selectivity, cost, speed, economy and simplicity.
    A. Reliability
    B. Compatibility
    C. Ruggedness
    D. None Ans. A
  7. interrupting contacts of a circuit breaker is a set of contacts which enable circuit

breaker to be removed.
A. Withdrawal
B. Disconnector
C. Plug in circuit breaker
D. Current limiting
E. Molded case Ans. B

  1. Which analysis deals with the effect of disturbances on power system?
    A. Fault trend analysis
    B. Sinusoidal analysis
    C. Stability analysis
    D. Line power analysis
    E. Load flow analysis Ans. C
  2. The of an equipment is specified by manufacturer the rating of circuit breaker as making rating.
    A. Rated making capacity
    B. Rated breaking capacity
    C. Rated ultimate short circuit breaking capacity
    D. Rated short circuit breaking capacity
    E. Rated short circuit making capacity Ans. E
  3. The terminal of an element is called or vertex is also called as
    A. Edge
    B. Limit
    C. Zero
    D. Node
    E. Rim Ans. D
  4. is defined as subgraph of connected element when not more than two elements connected to any node.
    A. Planar graph
    B. Path
    C. Route
    D. Linear graph
    E. Tree Ans. B
  5. is the point from where power is supplied to the induction motor.
    A. Stator
    B. Rotor
    C. Slip rings
    D. Commutator Ans. A
  6. Power switches are divided into groups.
    A. 2
    B. 4
    C. 5
    D. 7 Ans. A
  7. If F (jw) is the Fourier transform of function f(t), then
    A. £ f(-t) =F (jw)
    B. £ f(-t) =F * (jw)
    C. £ f (4) =F (-jw)
    D. £ f (4) =F *(- jw) Ans. B
  8. Binary of decimal 0.6875 is A. 1.1011
    B. 0.01011
    C. 0.1011
    D. None Ans. C
  9. Which of the following is not a basic component of a transformer?
    A. Primary winding
    B. Secondary winding
    C. Core
    D. Mutual flux Ans. D
  10. The faults due to lightning and storm damage are called
    A. Line to Line faults
    B. Single line to ground faults
    C. Double line to ground faults
    D. Ground to ground faults Ans. B

Electrical EngineeringI Smart Series MCQs COMPETITIVE EXAMS SET 12(1100-1218)

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