Where The electricity flows to a transmission station In the transmission station, a transformer changes a large current and low voltage into a small current and high voltage.. The other
Trang 1TRƯỜNG ĐẠI HỌC ĐIỆN LỰC Khoa: HỆ THỐNG ĐIỆN
ĐỀ THI KẾT THÚC HỌC PHẦN
MÔN: TIẾNG ANH CHUYÊN NGHÀNH
Đề thi số: 1
Full name:………
Class:………
I Multi-choice question
1 The current in a wire ………
a depends only on the potential difference
applied
c depends only on the resistance of the wire
b depends on both resistance and potential
difference
d does not depend on resistance and potential difference
2 One of the components in DC generators is :
3 Electrical generating is concerned with:
a power stations b planes c cables and switchgear d roads and bridges
4 One of the components in transformer is
5 Hydroelectric power plants use water flowing directly through the turbines to power the …
II Use the words in the box to complete the paragraph
If there is a …(1)… Fault in a piece of equipment then excessive current may flow This will cause overheating and possibly a fire; ….(2)… equipment protect against this happening Current from the supply to the equipment flows through the fuse The fuse is a piece of wire which can carry a stated current; if the …(3)…rises above this value it will melt
If the fuse melts (blows) then there is an open circuit and no current can then flow – thus protecting the equipment by …… (4)… Fuses it from the power supply The fuse must be able to carry slightly more than the normal operating current of the
…(5)… value to allow for tolerances and small current surges With some equipment there is a very large surge of current for
a short time at … (6)… milliseconds on If a fuse is fitted to ….(7)… current this large current there would be no protection against faults which cause the current to rise slightly above the normal ……(8)… Therefore special anti-surge fuses are fitted These can stand 10 times the rated current for 10 … (9)… If the surge lasts longer than this the fuse will … (10)…
III Sentence building
Join the following groups of sentences to make the longer sentences Use the words printed in italics at the beginning of each group You may omit words and make whatever changes you think are necessary in the word order and punctuation of the sentences.
a Where
The electricity flows to a transmission station
In the transmission station, a transformer changes a large current and low voltage into a small current and high voltage
b If
These gases and particulates are not captured by some pollution control equipment These gases and particulates are released into the atmosphere
Trang 2IV. Translate words into English and make a sentence with each word
1 Động cơ điện
2 Vành góp
3 Hiệu điện thế
4 Nhà máy nhiệt điện
5 Cầu dao
V Reading and comprehension
Read the following text and answer the questions
Electricity generation
Electricity generation is the process of generating electric energy from other forms of energy The basic method is still used today: electricity is generated by the movement of a loop of wire, or disc of copper between the poles of a magnet For electric utilities, it is the first process in the delivery of electricity to consumers The other processes, electricity transmission, distribution, and electrical power storage and recovery using pumped storage methods are normally carried out by the electric power industry
Electricity is most often generated at a power station by electromechanical generators, primarily driven by heat engines fueled by chemical combustion or nuclear fission but also by other means such as the kinetic energy of flowing water and wind There are many other technologies that can be and are used to generate electricity such as solar photovoltaics and geothermal power
Central power stations became economically practical with the development of alternating current power transmission, using power transformers to transmit power at high voltage and with low loss Electricity has been generated at central stations since 1881 The first power plants were run on water power or coal, and today we rely mainly on coal, nuclear, natural gas, hydroelectric, and petroleum with a small amount from solar energy, tidal harnesses, wind generators, and geothermal sources
Small electricity generators are often powered by reciprocating engines burning diesel, biogas or natural gas Diesel engines are often used for back up generation, usually at low voltages However most large power grids also use diesel generators, originally provided as emergency back up for a specific facility such as a hospital, to feed power into the grid during certain circumstances
Unlike the solar heat concentrators, photovoltaic panels convert sunlight directly to electricity Although sunlight is free and abundant, solar electricity is still usually more expensive to produce than large-scale mechanically generated power due
to the cost of the panels
Question:
1 Translate the first paragraph into Vietnamese?
2 What do the power plants nowadays run on?
3 What are the diesel generators used for?
4 Is the solar electricity cheap? Why?
Trang 3TRƯỜNG ĐẠI HỌC ĐIỆN LỰC Khoa: HỆ THỐNG ĐIỆN
ĐỀ THI KẾT THÚC HỌC PHẦN
MÔN: TIẾNG ANH CHUYÊN NGHÀNH
Đề thi số: 02
Fullname :
Class :
I Multi-choice question
1 The electric charge of an proton is equal to …
a +1,602×10-19C b -1,602×10-17C c +1,602×10-29C d -1,602×10-27C
2 One kilowatt hour of electrical energy is the same as…
a 36 x 105 watts b 105 watt c 36 x 105 joules d 36 megajoules
3 A circuit contains two un-equal resistances in parallel
a current is same in both b large current flows in larger resistor
c potential difference across each is same d smaller resistance has smaller conductance
4 In nature, energy cannot be created or ……, but its form can change
5 Filaments of electric bulbs are usually made of …
6 An object or a piece of equipment that has been designed to do a particular job
7 …… is not the component in motor
a commutator b field wingdings c transformer d drive shaft
8 A 160 V, 256 mW lamp has a working resistance of ……
9 ………is a passive electronic component consisting of a pair of conductors separated by a dielectric
10 Three 3 ohm resistors are connected to form a triangle What is the resistance between any two of the
corners?
II Use the words in the box to complete the paragraph
An ammeter is an instrument used to measure … current (1)…and must be connected … resistance (2)… with the circuit Since all the current in the circuit passes
through the ammeter, it must have a very ……(3)…
resistance
A …(4)…is an instrument used to measure p.d
and must be connected in parallel with the part of the
circuit whose p.d is required To avoid a significant
current flowing through it, a voltmeter must have a very
high…….(5)……
An ohmmeter is an instrument for …….(6)
…… resistance
A…(7)…, or universal instrument, may be used to
measure voltage, current and resistance An ‘Avometer’
and ‘Fluke’ are typical examples
…….(8)… may be used to observe waveforms and to measure voltages and currents The display of an oscilloscope involves a spot of light moving across a screen The amount by which the spot is …(9)… from its initial position depends on the p.d applied to the terminals of the oscilloscope and the range selected The displacement is ……(10)… in
‘volts per cm’
III Sentence building
Trang 4Join the following groups of sentences to make the longer sentences Use the words printed in italics at the beginning of each group You may omit words and make whatever changes you think are necessary in the word order and punctuation of the sentences.
a That
A direct-current (DC) generator is a rotating machine
A rotating machine supplies an electrical output with unidirectional voltage and current
b Where
In the transmission station, a transformer changes a large current and low voltage into a small current and high voltage The electricity flows to a transmission station
IV. Translate words into English and make a sentence with each word
1 Pin quang điện
2 Máy cắt điện
3 Nhà máy thủy điện
4 Từ trường
5 Chổi than
V. Reading and comprehension.Read the following text and answer the questions.
Electric power system
An electric power system is a network of electrical components used to supply, transmit and use electric power An example of an electric power system is the network that supplies a region's homes and industry with power - for sizable regions, this power system is known as the grid and can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centers to the load centers and the distribution system that feeds the power to nearby homes and industries
The majority of these systems rely upon three-phase AC power - the standard for large-scale power transmission and distribution across the modern world Specialized power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners and automobiles
Most refrigerators, air conditioners, pumps and industrial machinery use AC power whereas most computers and digital equipment use DC power (the digital devices you plug into the mains typically have an internal or external power adapter to convert from AC to DC power) AC power has the advantage of being easy to transform between voltages and is able to be generated and utilized by brushless machinery DC power remains the only practical choice in digital systems and can be more economical to transmit over long distances at very high voltages)
The ability to easily transform the voltage of AC power is important for two reasons: Firstly, power can be transmitted over long distances with less loss at higher voltages So in power systems where generation is distant from the load, it is desirable to step-up (increase) the voltage of power at the generation point and then step-down (decrease) the voltage near the load Secondly, it is often more economical to install turbines that produce higher voltages than would be used by most appliances, so the ability to easily transform voltages means this mismatch between voltages can be easily managed
Question:
1 Translate the first paragraph into Vietnamese?
2 Where is power system not – AC found?
3 How can the digital devices use DC power?
4 How can power be transmitted over long distance?