Câu 1:
The unit of the active poweris
- Watt-Hour
- Volt-Ampere Reactive
- Watt
- Volt-Ampere
Câu 2:
Resistance of a wire is R ohms. The wire is stretched to double its length, then its resistance in ohms is
Câu 3:
The unit of the reactive poweris
- Watt-hour
- Watt
- Volt-Ampere Reactive
- Volt-Ampere
Câu 4:
Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them are in the ratio :
Câu 5:
The unit of the apparent poweris
- Watt-hour
- Watt
- Volt-Ampere
Câu 6:
Four cells each of e.m.f 'E' are joined in parallel to form a battery. The equivalent e.m.f of the battery will be …………..
Câu 7:
The unit of electric resistanceis
- Siemens
- Tesla
- Ohm
- Coulomb
Câu 8:
Three 3 ohm resistors are connected to form a triangle. What is the resistance between any two of the corners?
- 3/4 ohms
- 2 ohms
- 4/3 ohms
- 3 ohms
Câu 9:
The unit of chargeis
- Siemens
- Tesla
- Coulomb
- Ohm
Câu 10:
The power factor is a ratio of ……...
- Real power to reactive power
- Real power to apparent power
- Reactive power to apparent power
- Reactive power to real power
Câu 11:
The unit of conductanceis
- Ohm
- Tesla
- Siemens
- Coulomb
Câu 12:
A circuit contains two un-equal resistances in parallel
- smaller resistance has smaller conductance
- potential difference across each is same
- large current flows in larger resistor
- current is same in both
Câu 13:
Ampereis the unit of
- Impedance
- Voltage
- Current
- Energy
Câu 14:
A coil of inductance 150mH and zero resistance is connected across a 100V, 50Hz supply. The inductive reactanceof the coil is:
- 41,72Ω
- 47,12Ω
- 47,72Ω
- 42,17Ω
Câu 15:
Ohmis the unit of
- Current
- Voltage
- Impedance (trở kháng)
- Energy
Câu 16:
A coil which has a resistance of 2Ω is connected to a 20V DC supply. Which is the value of current?
Câu 17:
Jouleis the unit of
- Impedance
- Voltage
- Energy
- Current
Câu 18:
Calculate the capacitive reactance value of a 220nF capacitor at a frequency of 1kHz.
- 734,2Ω
- 723,4Ω
- 744,2Ω
- 732,2Ω
Câu 19:
Voltis the unit of
- Electric Circuit
- Electric Current
- Potential Difference
- Volt-meter
Câu 20:
In the alternative current circuit, which of following statements is correct?
- The voltage across a capacitor leads the current by 90°.
- The voltage across a capacitor lags the current by 90
- The voltage across a capacitor in phase the current
- All 3 statement above are true.
Câu 21:
Ampereis the unit of
- Electric Circuit
- Voltage
- Electric Current
- Volt-meter
Câu 22:
Electrical generating is concerned with ………….
- Planes
- Power station
- Cables and switchgear
- Roads and bridges
Câu 23:
Write out V 1 = V 2 + V 3 in full
- Voltage one equals Voltage two plus Voltage three
- V one equal to V two plus V three
- V one equals V two plus V three
- Voltage one equals Voltage two minus Voltage three
Câu 24:
When there is an electric current passing through a wire, the particles moving are ..............
- Ions
- Molecules
- Electrons
- protons
Câu 25:
Write out V 2 + V 3 = V 1 in full
- Voltage two plus Voltage three is equal to Voltage three
- V one equals V two plus V three
- V two plus V three is equal to V one
- V two plus V three equal to V one
Câu 26:
Electric generators transform kinetic energy(động năng) into electricity.
- Renewable energy
- Classic energy
- Kinetic energy
- Potential energy
Câu 27:
The symbol of resistanceis
Câu 28:
Which one is the classic energysources used in electrical power generation.
- Hydroelectric energy (năng lượng thủy điện)
- Solar (mặt trời)
- Wind (gió)
- Distributed generation
Câu 29:
The symbol of electric currentis
Câu 30:
Which kinds of fuels(nhiên liệu) are used in the thermal power plant(nhà máy nhiệt điện) for generating electricity?
- Water
- Coal (than)
- Solar (mặt trời)
- Tidal Harnesses (thủy triều)
Câu 31:
The symbol of potential differenceis
Câu 32:
Which type of substation is usually locatednear power plants ?
- Distribution substation (máy biến áp phân phối)
- Step-down transmission substation (MBA hạ áp)
- Step-up transmission substation (MBA truyền tải(tăng áp))
- Generation substation
Câu 33:
A source e.m.f of 5V provides a current of 5A for 1minute. How much energy is provided in this time? (E=VIT=5.5.60=1500(J)=1.5(KJ)).
Câu 34:
The ......... substations are constructed in the open air.
- underground
- distribution
- indoor
- outdoor
Câu 35:
A resistance of 5k ohm has a conductance of? G= 1/R = 1/(5.10³) =0,2x10⁻³s=0.2 ms
Câu 36:
One of the fuctions of a substation is to? (chức năng của trạm biến áp)
- convert electrical energy into mechanical energy
- consume electricity
- generate electricity
- change voltage from one level to others
Câu 37:
Write out R 2 + 15Ω = R 1 in full
- Resistance two plus fifteen ohms equals resistance one.
- R one minus R two equals fifteen ohms.
- R two plus fifteen ohms is equal toR one.
- R two plus fifteen multiplied by ohm is equal to R one.
Câu 38:
Substations usually consist of following devices:
- photovoltaic panels
- damps, turbines
- thermal generators, motors
- transformers, insulators, and circuit breakers
Câu 39:
Write out R 2 + 15Ω = R 1 in full
- Resistance two plus fifteen ohms equals resistance one.
- R one minus R two equals fifteen ohms.
- R two plus fifteen ohms is equal to R one.
- R two plus fifteen multiplied by ohm is equal to R one.
Câu 40:
Which devices are used to interurpt short-circuit currents in the power system?
- Current transformers
- Voltage transformers
- Isolators
- Circuit breakers
Câu 41:
“The sum of I one, I two, and I three equals I four” is the full expression of
- I 1 + I 2 & I 3 = I 4
- I4=I1+I2+I3
- I1+I2+I3=I4
- I+1+I+2+I+3=I4
Câu 42:
An electrical substation plays an important role in the electrical system as it acts as a bridge in transferring the electricity from the power plant to......
- systems
- motors
- power plants
- consumers
Câu 43:
“I one plus I two equals four fifths of I three” is the full expression of
- I1+I2=I3
- I1+I2=I3
- I1+I2=I3
- I3=I1+I2
Câu 44:
A distribution substation(trạm biến áp phân phối) .......... voltage to a value suitable for local loads.
- supports
- increases
- remains
- reduces
Câu 45:
Write out P = VIcos in full
- The active power equals the product of the voltage, the current, and power factor.
- P equals to the product of V, I, and cos.
- P equals the product of V, I, and cos.
- P equals the product of V, I, c, o, s, and .
Câu 46:
In switching substation, there is not any .......
- insulator
- isolator
- circuit breaker
- transfomer
Câu 47:
Write out Y = in full
- The reciprocal of Z is equal to Y.
- Z is equal to the reciprocal of Y.
- Y is equal to the reciprocal of Z.
- The admittance is equal to the reciprocal of the impedance.
Câu 48:
The power from ............. substations is distributed to industrial, commerccial, and residential customers.
- generation
- power
- transmission
- distribution
Câu 49:
Generation of electricity is a process whereby electrical energy is obtained from some other form of …...
Câu 50:
substations are built in urban areas to decrease the noise from the transformer for reasons of appearance, or to protect switchgear from extreme climate or pollution conditions.
- Distribution
- Transmission
- Outdoor
- Indoor
Câu 51:
Generation of …… is a process whereby electrical energy is obtained from some other form of energy.
- heat
- fuel
- electricity
- steam
Câu 52:
In ............, voltage is changed for transmission and distribution.
- inductrial factories
- commercial centers
- power stations
- substations
Câu 53:
A battery of e.m.f of 12 V supplies a current of 10 A for 6 minutes. How much energy is supplied in this time?
- 12 VAh
- 720VAh
- 7200 VAh
- 20VAh
Câu 54:
In transmission substations, the ........... is stepped up for transmission.
- capacitance
- power
- current
- voltage
Câu 55:
A current of 5 A flows through a conductor and 10 W dissipated. What voltage exists across the ends of the conductor?
- 2 V P=V.I 10=2.5
- 50V
- 0,5 V
- 0,2 V
Câu 56:
What is the main purpose of a distribution substation?
- to convert mechanical energy into electricity
- to generate electricity
- to transfer power from the distribution system to the transmission system
- to transfer power from the transmission system to the distribution system
Câu 57:
A conductor has a conductance of 0.1 S. It’s resistance is:
Câu 58:
What is the main purpose of a transmission substation?
- to convert mechanical energy into electricity
- to generate electricity
- to transfer power from the distribution system to the transmission system
- to connect various transmission lines together.
Câu 59:
A conductor has a resistance of 10 Ω. It’s conductance is:
Câu 60:
Substations may be owned and operated by an electrical utility, or may be owned by a large industrial or commercial ....
- people.
- administrators.
- operators.
- customers.
Câu 61:
What is the unit ofelectromotive force?( sức điện động)
Câu 62:
Smaller distribution stations may use ............ or fuses for protection protection of distribution circuits
- Isolators
- arrestors
- Disconnect switching devices
- recloser circuit breakers
Câu 63:
What does the “potential difference” mean?( định nghĩa của hiệu điện thế?)
- A change in resistance between two points in an electric circuit.
- A change in power between two points in an electric circuit.
- A change in electric current between two points in an electric circuit.
- A change in electric potentialbetween two points in an electric circuit.
Câu 64:
Other devices such as capacitors and ......... may also be located at a substation
- cooling tower
- governer
- current regulators
- voltage regulators
Câu 65:
What is the power factor? (hệ số công suất là gì?)
- The ratio of apparent power to reactive power.
- The ratio of apparent power to active power.
- The ratio of reactive power to apparent power.
- The ratio of active power to apparent power.
Câu 66:
Earth ....... at a substation can cause a ground potential rise
- disconnection switch
- devices
- wires
- faults
Câu 67:
What is the unit of mutual inductance? (Điện cảm)
Câu 68:
Where a substation has a metallic fence, it must be properly ........ , to protect people from this hazard.
- distributed
- isolated
- maintained
- grounded
Câu 69:
Power grid includes particular installations, substations, lines or cables for transmittingand …… of electricity.
- generating (phát ra)
- distribution (sự phân phối)
- distributing(phân phối)
- generation (sự phát ra)
Câu 70:
If all of the plant's main generators are shut down, station service power is supplied by drawing power from the .... through the plant's transmission line.
- plant's distribution line
- power transformer
- grid
- feeder
Câu 71:
An electric gridor power grid is an interconnected network for ……. electricityfrom producers to consumers.
- generating (phát điện)
- changing (biến đổi điện)
- delivering(cung cấp điện)
- consuming (tiêu thụ điện)
Câu 72:
The electric power which ...... is stepped up to a higher voltage at which it connects to the transmission grid.
- are generating
- generates
- is generated
- transformer
Câu 73:
Which equipment is used to produce electricity?(thiết bị dùng để sản xuất điện)
- Atransformer
- Amotor
- Acable
- A generator (máy phát điện)
Câu 74:
Electronic power conditioning and control of the production and distribution of electricity .... important aspects of the smart grid.
Câu 75:
convert the energy stored in the fuel (mainly coal, oil, natural gas, enriched uranium) or renewable energies (water, wind, solar) into electric energy.
- Transformers
- Consumers
- Substations
- Power plants
Câu 76:
Generation of electricity is a process whereby electrical energy is obtained from other form of ......
Câu 77:
Cogenerators are facilities that utilize heat for ........ electricity and for another form of useful thermal energy (steam or hot water).
- distributing
- maintaining
- consuming
- generating
Câu 78:
Generation of ...... is a process whereby electrical energy is obtained from some other form of energy
- heat
- fuel
- electricity
- steam
Câu 79:
Conventional generators produce electricity at a ............ that is a multiple of the rotation speed of the machine.
- power
- voltage
- current
- frequency
Câu 80:
A substation is a part of an electrical ......., transmission,and distributionsystem.
- generator
- generating
- generation
- power plant
Câu 81:
Where electricity is generated?
- In transmission lines
- In transmission substations
- In distribution substations
- In power plants
Câu 82:
Power grid includes particular installations, substations, lines or cables for transmitting and ...... of electricity.
- generating
- distribution
- distributing
- generation
Câu 83:
What are the norminal voltages of the transmission system in Vietnam?
- 22 kV, 35 kV
- 6 kV, 10 kV
- 220 V, 380 V
- 220 kV, 500 kV
Câu 84:
An electric grid or power grid is an interconnected network for ........ electricity from producers to consumers.
- generating
- changing
- delivering
- consuming
Câu 85:
Generation, transmission and distribution system are parts of .........
- A consumer
- A power plant
- A substation
- an electric power system
Câu 86:
is a structure used in electric power transmission and distribution to transmit electrical energy across large distances.
- A generator
- A reactor
- A capacitor bank
Câu 87:
What is the electric power system?
- Lines and transformers
- Transmisstion systems
- Loads
- A very large network that links power plants to loads
Câu 88:
An overhead power line consists of one or more conductors suspended by ....... or poles.
- isolators
- capacitors
- resistors
- towers (cột điện)
Câu 89:
Generators provide nearly all of the ………. for electric power grids.
- frequency
- current
- voltage
- power
Câu 90:
Since most of the ......... is provided by air, overhead power lines are generally the lowest-cost method of power transmission for large quantities of electric energy.
- tranformation
- distribution
- conduction
- insulation
Câu 91:
Four letters c in “The 4C approach to successful business writing” stand respectively for ...
- Complex, Concise, Correct, and Courteous
- Countable, Concise, Correct, and Comprehensive
- Clear, Concise, Correct, and Courteous
- Correlative, Clear, Concise, and Corect
Câu 92:
Write out P = VIcos in full
- The active power equals the product of the voltage, the current, and power factor.
- P equals to the product of V, I, and cos.
- P equals the product of V, I, and cos.
- P equals the product of V, I, c, o, s, and .
Câu 93:
the current in a wire………….
- depends only on the resistance of the wire
- does not depend on resistance and potential difference
- depends only on the potential difference applied
- depend on both resistance and potential difference
Câu 94:
The most common conductor in use for transmission today is ..........
- copper bar
- lightning cable
- power cable
- aluminum conductor steel reinforced (ACSR).
Câu 95:
one kilowatt hour of electrical energy is the same as……..
- 36 x 10⁵ B.T.U
- 36 x 10s ergs
- 36 x 10⁵ watt
- 36 x 10⁵ joules
Câu 96:
The ground conductor is usually grounded at the top of the supporting structure, to minimize the likelihood of direct ......... to the phase conductors.
- overload currents
- under voltage sags
- short circuit currents
- lightning strikes (sét đánh)
Câu 97:
In the Internation System of Units, the unit of conductance(điện dẫn) is ........
Câu 98:
Power ......... comprise a number of conducting cores of copper or aluminium, insulation, and armouring.
- towers
- insulators
- bare wires
- cables
Câu 99:
The instantaneous values of a sinusoidal waveform is given by the formula :
- Vi= Vmaxtgot
- Vi= Vmaxcosωtsinωt
- Vi=Vmaxcosωt
- Vi= V maxsinωt
Câu 100:
In transmission substations, the ........... is stepped up for transmission.
- capacitance
- power
- current
- voltage
Câu 101:
For any node in ............, the sum of currents flowing into that node is equal to the sum of currents flowing out of that node; or equivalently:
- Counter
- Electric power plante
- An winding
- An electrical circuit
Câu 102:
Residential customers are supplied with .......... levels of 220/380 V
- potential
- electromotive force
- current
- voltage
Câu 103:
The Hertz is defined as:
- Minutes per cycle
- Seconds per cycle
- Cycles per one minute
- Cycles per one second
Câu 104:
is a device designed to detect the faults in the power system.
- Boiler
- Current transformer
- Turbine
- Protective relay
Câu 105:
A coil of inductance 150mH and zero resistance is connected across a 100V, 50Hz supply. The current flowing through the reactance is :
Câu 106:
carry power from the generators to the loads.
- Inductors
- Resistors
- Capacitors
- Conductors (dây dẫn)
Câu 107:
A coil which has an inductance of 40mH and a resistance of 2Ω is connected together to form a LR series circuit. If they are connected to a 20V DC supply. Which is the final steady state value of the current ?
Câu 108:
An electric current running through a wire produces ... around the wire
- an electromanet
- a current
- a magnetic field (từ trường)
- an electric field
Câu 109:
What will be the value of a capacitor in farads when it has a capacitive reactance of 200 Ω and is connected to a 50Hz supply.
- 15,29uF
- 12,59uF
- 19,22uF
- 15,92uF
Câu 110:
What is the main purpose of a transmission substation?
- to convert mechanical energy into electricity
- to generate electricity
- to transfer power from the distribution system to the transmission system
- to connect various transmission lines together.
Câu 111:
In power system, which of following statements is correct ?
- The device which takes electrical energy is known as the electric load
- The source which generate electrical energy is known as the electric load
- a dam is considered as a load
- a transformer being separed from the power network is considered as a load
Câu 112:
The reverse conversion of electrical energy into mechanical energy is done by an electric.........
- transformer
- gennerator
- circuit breaker
- motor
Câu 113:
Hydroelectric power plants used water flowing directly through the turbines to power the
- Boiler
- Generator
- Reactor
- Dam
Câu 114:
is the stationary part of a generator.
- Drive shaft
- Armature
- Rotor
- Stator
Câu 115:
Filaments of electric bulbs are usually made of ………….
- Nichrome
- Tungsten
- Copper
- Carbon
Câu 116:
Primary of a ........... is connected in serieswith the power circuit.
- boiler
- turbine
- votage transformer
- current transformer
Câu 117:
are used to "transform" voltage from one level to another.
- Motor
- Generator
- Transformer
- Insulator
Câu 118:
Primary of a ........... is connected in parallelwith the power circuit.
- boiler
- circuit breaker
- current transformer
- votage transformer
Câu 119:
Resistance of a wire is R ohms. The wire is stretched to double its length, then its resistance in ohms is
Câu 120:
feeds power from one point to another without being tapped from any intermediate point.
- Transformer
- Circuit breaker
- Generator
- Feeder
Câu 121:
The consumer in the ....... electrical distribution system will be in darkness if feeder or transformer are failured.
- double-feed
- loop
- ring
- radial
Câu 122:
Ring network is fed by more than one..........
- consummer
- bus
- circuit breaker
- feeder
Câu 123:
Motor converts electrical energy into ....... energy.
- solar
- wind
- chemical
- mechanical
Câu 124:
does not readily release electrons
- Cooper
- Aluminum
- Steel
- Rubber
Câu 125:
Electrical installation is concerned with ........
- power stations
- factories
- roads and bridges
- cables and switchgears
Câu 126:
Electric power network includes particular installations, substations, lines or cables for the transmission and distribution of………...
- heat.
- water.
- electricity.
- energy.
Câu 127:
Substations may be owned and .... by an electrical utility.
- operating
- operation
- operated
- operators
Câu 128:
Substations may be owned by a large industrialor ....... customer.
- commercing
- commerces
- commercial
- commerced
