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ELECTRICAL 1
  • Gaviola Jayson, Alab

  • 問題数 100 • 1/23/2024

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    問題一覧

  • 1

    A PERMEABLE (NATATAGUSAN) SUBSTANCE IS ONE

    through which the magnetic lines of force can pass very easily

  • 2

    the customer is only charged or credited as the case may be, for the difference between the electricity supplied by the distribution utility and electricity it supplies to the distribution utility when the times it has excess VRE generation both of which are using either 2 unidirectional meters one for import and for export or a single bidirectional meter

    Net Metering

  • 3

    Electric Field lines are close together where the field is large

    true

  • 4

    If a tropical storm is going to the Philippine Area of Responsibility within 24 hours what type of alert is to be raised in accordance with the Philippine Grid Code

    Blue Alert

  • 5

    for any circuit the number of independent equations containing emfs resistances and currents equals the number of ______

    branches

  • 6

    In the context of the loop and junctions rules for electrical circuits a junction is where_____

    three or more wires are joined

  • 7

    which of the following statement is false

    windows 98 is RTOS

  • 8

    Determine the GMR of a three-equal strands conductors in vertical formation in terms of r of an individual strand

    1.7036 r

  • 9

    A cylindrical copper rod has resistance R. It is reformed to twice its original length with no change in volume. What is its new resistance?

    4R

  • 10

    DMC stands for? created by ERC in compliance to PDC

    Distribution Management Committee

  • 11

    the rms value value of ac current is

    that steady current that produces the same rate of heating in resistor as the actual current.

  • 12

    it refers to the powerloss due to alternating magnetization and demagnetization of the core material

    hysterisis loss

  • 13

    Which of the following is the following is the correct statement about coulomb?

    the amount of charge that flows a past point in one second when the current is one ampere

  • 14

    When a dc motor has no load, what will happen to the back emf?

    becomes maximum

  • 15

    synchronizing power of a synchronous machine is

    inversely proportional to the synchronous reactance

  • 16

    It is a device which functions on failure of a machine, transformer or of other apparatus to ground or on flash over of a dc machine to ground

    ground protective relay

  • 17

    the total load on any overcurrent device located in a panelboard shall not exceed ___ of its rating where the normal operation the load will continue for three hours or more

    80%

  • 18

    the region or area in a transistor that is heavily doped

    emitter

  • 19

    GMC was created by the Energy Regulatory Commision to monitor the compliance of the users of the Grid to the PGC. What does the GMC stands for?

    Grid Management Committee

  • 20

    It is possible to increase the field flux and, at the same time, increase the speed of a dc motor provided its _______ is held constant

    Armature current

  • 21

    It is considered as the heart of a dc machine

    Armature winding

  • 22

    While describing the shealth of a cable, the abbreviation XLPE means _____________ polyethylene

    cross-linked

  • 23

    Conductors supplying two or more motors shall have an ampacity equal to the sum of the following current rating of all the motors plus ______% of the highest rated motor in the group

    25

  • 24

    Megger essentially is a

    megohmmeter

  • 25

    Which of the following cannot have a single unit of 100 MW

    Diesel power plant

  • 26

    Chemicals with lower flash points presents a greater ______

    Flammability hazard

  • 27

    What is the maximum number of conductors in a raceway that does not need to be derated

    3

  • 28

    Which of the following type of fault used only the equivalent positive sequence impedance of the circuit in the short circuit calculation

    Three phase fault

  • 29

    Which of the following insulators will be selected for high voltage application

    Suspension type

  • 30

    Base load plants are designed to supply power at

    high capital cost and low operating cost

  • 31

    Which is not a characteristics of an ideal transformer

    finite permeability

  • 32

    What is the IEEE device function number 50

    Instantaneous overcurrent relay

  • 33

    Transformer breaths in when

    load on it decreases

  • 34

    The color reserved for use in equipment grounding conductor is

    Green

  • 35

    Joule found out that the heat produced in a current carrying conductor is proportional to

    the square of the current

  • 36

    The applied voltage in a transformer is increased by 50% and frequency is reduced by 50%. The maximum core flux density will become

    3 times

  • 37

    A battery is used to change a parallel plate capacitor, after which it is disconnected.Then the plates are pulled apart to twice their original separation. This process will double the :

    Stored energy

  • 38

    A step-down transformer is used to

    decrease the voltage

  • 39

    Iron, rather than copper, is used in the core of transformers because iron:

    has a very high permeability

  • 40

    The tesla is a unit of

    magnetic flux density

  • 41

    Which of the following statements regarding the motion of a conductor through a changing magnetic field is FALSE

    The conductor must move at constant velocity in order to generate a current

  • 42

    A DC system can be protected from lightning by including a thyrite tube in the circuit that connects the high voltage line with the ground. Which of the following is FALSE regarding a thyrite tube?

    Its fusable link melts at high voltages

  • 43

    Which of the following statements regarding transformer is FALSE

    One three phase transformer weighs more than three equivalent single phase transformer

  • 44

    For an existing a.c. transmission line the string efficiency is 80%. Now if d.c voltage is supplied for the same set up, the string efficiency will be:

    100%

  • 45

    The inductance per unit length of an overhead line due to internal flux linkages

    Is independent of the size of conductor and constant

  • 46

    High permittivity ceramic is used for capacitors of

    A few uF to a few hundred uF

  • 47

    What are the causes of gross error in the instrument 1. Misreading of instruments 2. Incorrect adjustment of instruments 3.Errors due to defective instruments 4.Errors due to effort of environment on the instrument

    1 and 2

  • 48

    The phase shift between the current and voltage vectors is due to the following except one

    electric flat iron

  • 49

    An aternating voltage is given by v=100 sin 314t volts. Its average value will be

    63.7 V

  • 50

    It is desired to have a constant direct current i(t) through the ideal inductor L. The nature of the voltage source v(t) must

    an ideal impulse

  • 51

    The ordinary efficiency of a given transformer is maximum when

    its Cu loss equals iron loss

  • 52

    Receptacles installed on 15- and 20- ampere branch circuits must always be of what type

    Grounding type

  • 53

    In a circuit breaker the time duration from the instant of energizing of the trip coil is known as

    protection time

  • 54

    Over voltage protection is recommended for

    All of these

  • 55

    What is the fourth harmonic of 800 KHZ

    3.20 MHZ

  • 56

    The fuse used for the overhead primary distributors is

    expulsion

  • 57

    Peak load plants are designed to supply power at

    low capital cost and high operating cost

  • 58

    Which of the following principle will the operation of fiber optic cable is based

    reflection

  • 59

    In a wye connected system, line current is

    equal to the phase current

  • 60

    A device that establishes an electrical connection to the earth

    Grounding electrode

  • 61

    What determines the direction of force in a conductor

    Left hand rule

  • 62

    In a parallel circuit, the potential difference across the resistance

    is always constant

  • 63

    Based on the Philippine Distribution code (PDC), the Distributor may establish penalties for Users whose power factors are less than

    85%

  • 64

    An Act to ensure and accelerate the total electrification of the Philippines, also known as EPIRA law of 2001

    RA 9136

  • 65

    If we increase field current of a dc generator, its emf output

    increases till the magnetic saturation takes place

  • 66

    Armature reaction in an alternator primarily affects

    generated voltage per phase

  • 67

    What is the equivalent of the collector terminal of transistor in a FET

    Drain

  • 68

    Branch circuit conductors supplying a single motor shall have an ampacity NOT less than _____ percent of the motor full load current rating

    125

  • 69

    Ten oersted is equivalent to

    0.1cm/GB

  • 70

    The transients which are produced due to sudden but energetic changes from one steady state of a circuit to another are called

    Transition

  • 71

    The relative polarity of the winding of a transformer may be determined by

    phasing out

  • 72

    When luminaires direct 90 to 100% of their output upward is considered a

    Indirect lighting

  • 73

    Which of the following limits the number of coils that may be placed on the armature of a DC motor or generator

    coil to coil arcing due to the breakdown of insulation

  • 74

    A transformer has negative voltage regulation when its power factor is

    leading

  • 75

    When a step input is applied to a second order circuit, the final values of the circuit variables are found by

    Replacing capacitors with open circuits and inductors with closed circuits

  • 76

    Power factor can be improved by connecting which among these

    Static capacitors and synchronous condensers

  • 77

    Which of the following is NOT a reason why single-phase induction motor run

    hysteresis

  • 78

    What is the device function number of overvoltage relay

    59

  • 79

    "Debye" is the unit of

    Electric dipole moment

  • 80

    Relay used for feeder protection is

    translay relay

  • 81

    Electric hazards include shock, electric arcs and blasts and ____ or faulty equipment

    Broken

  • 82

    The resistance of a semiconductor is known as

    bulk resistance

  • 83

    What does the fourth loop of an electronic resistor color code represent

    Tolerance

  • 84

    Auxiliary gutters shall not contain more than ______ current carrying conductors at any cross section

    30

  • 85

    In the list below, which ine is not a type of present day nuclear power plant

    fussion fission reactor

  • 86

    The ratio of the average load on the plant for the period of time considered to the aggregate rating of all the generating equipment

    Capacity factor

  • 87

    In an ideal transformer

    All of these

  • 88

    The full load copper loss in a transformer is 400 watts. At half load, the copper loss will be

    100 watts

  • 89

    In a HRC fuse the time between cut-off and final current zero, is known as

    arcing time

  • 90

    The advantage of the ring main system is

    Continuity of supply to feeding points

  • 91

    When the stator windings are connected in such a fashion that the number of poles are made half, the speed of the rotor of a synchronous motor

    increases to two times the original value

  • 92

    The imaginary or fictitious part of synchronous reactance takes care of

    armature reaction

  • 93

    The electrical analog of a spring constant k is:

    1/C

  • 94

    A 2-uF and a 1-uF capacitor are connected in series and a potential difference is applied across the combination. The 2 -uF capacitor has

    half the potential difference of the 1-uF capacitor

  • 95

    A "coulomb" is

    the amount of charge that flows past a point in one second when the current is 1 A

  • 96

    The tesla is a unit of

    magnetic flux density

  • 97

    Induction generators deliver power at

    Leading power factor only

  • 98

    The wire with the highest temperature rating is

    THHN

  • 99

    As substance that changes it electrical resistance when illuminated by light is called

    Photoconductive